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2000 cadillac deville, slushing sound in dash, overheating


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Please help. 2000 cadillac deville northstar engine, 134,000 miles, motor was pulled and gone thru 3-4 yrs ago, started to overheat week ago. Gauge went to hot and messages came on "coolant hot, idle, ac off" or something like that. No white smoke, oil is normal color so hope it isnt the HG.

Have replaced the thermostat, water pump, water temp sensor, cap and it still has the temp gauge going over the middle (normal) line at times. Driving around town it stays normal, then on hiway several miles (maybe 20-30 miles) it will go up one notch or sometimes two, turn on heater and kick it out of gear will bring it back down.

Coolant is flowing from purge line by coolant tank, fans are coming on OK, heat coming out of heater OK.

Tonight when I stopped it, I heard a "slushing noise" coming from the dash ( or at back of motor), sounding like water moving, when I reved it up. Is that from air being trapped in heater core (read that somewhere).

Just changed out the water pump yesterday so this morning I put it on a hill nose up, cap off, heater and fan on, ran till norm temp and fans came on, coolant level went down, refilled it.

Also the "check coolant level" message is on, (but it has been on before, even when full) tank is on right level. CAN this have anything to do with overheating? Also had replaced reservoir some time ago and used a differnt brand 50/50 coolant mix. Sometimes the dash lights go to dim, turn the car off and they come back bright when restarted. Trying to point out anything that may cause overheating.

We cant find any purge valve or screw on this car. Does anyone know where it is, if there is one? And what I should do next? How confusing is cars?

Edited by cadillac cowgirl
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There is no "purge valve" - any air in the system is purged by the line that runs from the throttle body area to the surge tank. If the coolant in the surge tank is at the proper level and the CHECK COOLANT LEVEL message is displayed, the coolant level sensor is defective. This is totally unrelated to the overheating issue though.

That was the reason the engine was "gone through" 3-4 years ago? Headgaskets? If so, was the engine block Timeserted?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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There is no "purge valve" - any air in the system is purged by the line that runs from the throttle body area to the surge tank. If the coolant in the surge tank is at the proper level and the CHECK COOLANT LEVEL message is displayed, the coolant level sensor is defective. This is totally unrelated to the overheating issue though.

That was the reason the engine was "gone through" 3-4 years ago? Headgaskets? If so, was the engine block Timeserted?

That was exactly what I was going to ask. If the engine block wasn't timeserted, then the job may as well have not been done. The head bolts will almost always pull if they have been removed and put back in without the block being re-threaded.

The slushing sound you mention makes me think of the heater core as a possibility as well. From what I have been told, if the heater core is leaking, it will normally form a puddle or wet spot of coolant on the passenger-side floor under the dash. I would check that out.

Also, you should pull the Diagnostic Codes to see if there are any and post them here. Even codes that show up as History can be relevant, so post those as well. If you don't know how to pull codes, go here. It will tell you how. http://www.caddyinfo.com/readingcodes.html

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You have all the classic symptoms of a breached HG. Stop throwing parts at it and rent a block test kit or buy one from Napa and test the air in the surge tank for exhaust gases. That will rule them out or condemn them before throwing any more parts at it.

Why does everyone change a water pump to try and cure an overheat situation. If the water pump is not leaking, its good and doing its job.

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Why does everyone change a water pump to try and cure an overheat situation. If the water pump is not leaking, its good and doing its job.

I've always kind of wondered that too. The only other time you would need to replace besides it leaking would be if it seizes. Happened to me on my 95 Seville. Shredded the belt right off.

I actually have a block tester, but I'm sure you're not anywhere close to Minot, ND.

-Dusty-

2006 Cadillac DTS Glacier Gold Tri-Coat with 175,000 miles

1993 Cadillac Sixty Special Gold Mist with 185,000 miles

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Why does everyone change a water pump to try and cure an overheat situation. If the water pump is not leaking, its good and doing its job.

I've always kind of wondered that too. The only other time you would need to replace besides it leaking would be if it seizes. Happened to me on my 95 Seville. Shredded the belt right off.

I actually have a block tester, but I'm sure you're not anywhere close to Minot, ND.

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Why does everyone change a water pump to try and cure an overheat situation. If the water pump is not leaking, its good and doing its job.

I've always kind of wondered that too. The only other time you would need to replace besides it leaking would be if it seizes. Happened to me on my 95 Seville. Shredded the belt right off.

I actually have a block tester, but I'm sure you're not anywhere close to Minot, ND.

I dont know why the water pump was changed, I am far from a mechanic (and a blond female with dyed hair LOL) However I went to the NORTHSTARPERFORMANCE.COM website and did the little 30mph to 70 several times today, as they say and I read someplace else that is the only way on Northstar the HG can be correctly checked. The temp gauge stayed right on normal. THEN I pulled back into my lane let it run for maybe 10 min, still was normal then turned on the AC and drove about one mile and it went to HOT, with message of HOT ENGINE< AC OFF. (I have left the AC on before and left it idle for an hour and no movement in the gauge off of normal, also took it several miles with AC on last week and it did finally go up one notch.)

I havent did the block test, and wish I was closer to you 93 but I live in Kansas a little far to borrow it from you. But thanks anyway.

The engine was pulled a few years back, before I got the car for an oil leak and all new seals, new gaskets, they went thru the motor, my son is a mechanic ( he has given up on the reason it overheats) and knew the owner and the place that did the work, he doesnt believe it is a head gasket, but he may be wrong. It was done by one of the best companies here so hopefully they did it right for the HG.

I again put the front end up a hill this evening, pulled the cap off, ran the heater and fan, got antifreeze all over the place from bubbling over, but I cant hear the sound of water tonight coming from the heater portion-but tomorrow is another day?

I also pulled up the codes tonight, first time I did that, thanks, but they only list the things on that website that doesnt pertain to any problem areas that I see. Will try to find somewhere that lists the exact ones I got, there are so many, with HISTORY, that it probably hasnt been reset since it was new.

Thank you all for your imput, I hope someone comes up with a solution and I dont have to give up my pretty cadillac to the boneyard.

Edited by cadillac cowgirl
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Why does everyone change a water pump to try and cure an overheat situation?

That, and the radiator is usually changed needlessly also...

Why does everyone change a water pump to try and cure an overheat situation. If the water pump is not leaking, its good and doing its job.

I've always kind of wondered that too. The only other time you would need to replace besides it leaking would be if it seizes. Happened to me on my 95 Seville. Shredded the belt right off.

I actually have a block tester, but I'm sure you're not anywhere close to Minot, ND.

I dont know why the water pump was changed, I am far from a mechanic (and a blond female with dyed hair LOL) However I went to the NORTHSTARPERFORMANCE.COM website and did the little 30mph to 70 several times today, as they say and I read someplace else that is the only way on Northstar the HG can be correctly checked. The temp gauge stayed right on normal. THEN I pulled back into my lane let it run for maybe 10 min, still was normal then turned on the AC and drove about one mile and it went to HOT, with message of HOT ENGINE< AC OFF. (I have left the AC on before and left it idle for an hour and no movement in the gauge off of normal, also took it several miles with AC on last week and it did finally go up one notch.)

I havent did the block test, and wish I was closer to you 93 but I live in Kansas a little far to borrow it from you. But thanks anyway.

The engine was pulled a few years back, before I got the car for an oil leak and all new seals, new gaskets, they went thru the motor, my son is a mechanic ( he has given up on the reason it overheats) and knew the owner and the place that did the work, he doesnt believe it is a head gasket, but he may be wrong. It was done by one of the best companies here so hopefully they did it right for the HG.

I again put the front end up a hill this evening, pulled the cap off, ran the heater and fan, got antifreeze all over the place from bubbling over, but I cant hear the sound of water tonight coming from the heater portion-but tomorrow is another day?

I also pulled up the codes tonight, first time I did that, thanks, but they only list the things on that website that doesnt pertain to any problem areas that I see. Will try to find somewhere that lists the exact ones I got, there are so many, with HISTORY, that it probably hasnt been reset since it was new.

Thank you all for your imput, I hope someone comes up with a solution and I dont have to give up my pretty cadillac to the boneyard.

There are two methods to check for a bad headgasket - one is the block test kit that tests the coolant for combustion gasses. The other is to pressurize each cylinder with shop air while the cylinder is at top dead center on the compression stroke. Any bubbles in the surge tank = bad headgasket.

A cheap test would be to have the radiator cap tested to assure it holds pressure. Any radiator shop should be able to do this for you. If the cap tests good, then the radiator shop could test the coolant for combustion gasses.

There is the possibility the shop that did the work on the engine removed the heads and did not Timesert the headbolt holes. If that is the case, the headbolts may have started to pull.

A bad headgasket is not the end of the world... it can be fixed.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Why does everyone change a water pump to try and cure an overheat situation?

That, and the radiator is usually changed needlessly also...

Why does everyone change a water pump to try and cure an overheat situation. If the water pump is not leaking, its good and doing its job.

I've always kind of wondered that too. The only other time you would need to replace besides it leaking would be if it seizes. Happened to me on my 95 Seville. Shredded the belt right off.

I actually have a block tester, but I'm sure you're not anywhere close to Minot, ND.

I dont know why the water pump was changed, I am far from a mechanic (and a blond female with dyed hair LOL) However I went to the NORTHSTARPERFORMANCE.COM website and did the little 30mph to 70 several times today, as they say and I read someplace else that is the only way on Northstar the HG can be correctly checked. The temp gauge stayed right on normal. THEN I pulled back into my lane let it run for maybe 10 min, still was normal then turned on the AC and drove about one mile and it went to HOT, with message of HOT ENGINE< AC OFF. (I have left the AC on before and left it idle for an hour and no movement in the gauge off of normal, also took it several miles with AC on last week and it did finally go up one notch.)

I havent did the block test, and wish I was closer to you 93 but I live in Kansas a little far to borrow it from you. But thanks anyway.

The engine was pulled a few years back, before I got the car for an oil leak and all new seals, new gaskets, they went thru the motor, my son is a mechanic ( he has given up on the reason it overheats) and knew the owner and the place that did the work, he doesnt believe it is a head gasket, but he may be wrong. It was done by one of the best companies here so hopefully they did it right for the HG.

I again put the front end up a hill this evening, pulled the cap off, ran the heater and fan, got antifreeze all over the place from bubbling over, but I cant hear the sound of water tonight coming from the heater portion-but tomorrow is another day?

I also pulled up the codes tonight, first time I did that, thanks, but they only list the things on that website that doesnt pertain to any problem areas that I see. Will try to find somewhere that lists the exact ones I got, there are so many, with HISTORY, that it probably hasnt been reset since it was new.

Thank you all for your imput, I hope someone comes up with a solution and I dont have to give up my pretty cadillac to the boneyard.

There are two methods to check for a bad headgasket - one is the block test kit that tests the coolant for combustion gasses. The other is to pressurize each cylinder with shop air while the cylinder is at top dead center on the compression stroke. Any bubbles in the surge tank = bad headgasket.

A cheap test would be to have the radiator cap tested to assure it holds pressure. Any radiator shop should be able to do this for you. If the cap tests good, then the radiator shop could test the coolant for combustion gasses.

There is the possibility the shop that did the work on the engine removed the heads and did not Timesert the headbolt holes. If that is the case, the headbolts may have started to pull.

A bad headgasket is not the end of the world... it can be fixed.

thanks again, I have another question, dumb or not, here it goes. I read too much on the internet---however can a thermostat, on this 2000 cadillac deville be put in wrong, like upside down or I read somewhere that the hole? has to be on top?????

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Yes, it can be installed backwards.

I again put the front end up a hill this evening, pulled the cap off, ran the heater and fan, got antifreeze all over the place from bubbling over,

That COULD be from running the engine too long with the cap off. With the cap on, the system gets pressurized, which raises the coolants boiling point to about 265 degrees. With the cap off, a 50/50 mixture will boil at about 225 (I think). You can only run it for 5 minutes or so without the cap before it boils over. If it happened right after start up with a cold engine, then it is "false boiling" caused by exhaust gases in the cooling system pushing the coolant out. Have the block test done and good luck. Keep us advised.

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There is no "purge valve" - any air in the system is purged by the line that runs from the throttle body area to the surge tank. If the coolant in the surge tank is at the proper level and the CHECK COOLANT LEVEL message is displayed, the coolant level sensor is defective. This is totally unrelated to the overheating issue though.

That was the reason the engine was "gone through" 3-4 years ago? Headgaskets? If so, was the engine block Timeserted?

That was exactly what I was going to ask. If the engine block wasn't timeserted, then the job may as well have not been done. The head bolts will almost always pull if they have been removed and put back in without the block being re-threaded.

The slushing sound you mention makes me think of the heater core as a possibility as well. From what I have been told, if the heater core is leaking, it will normally form a puddle or wet spot of coolant on the passenger-side floor under the dash. I would check that out.

Also, you should pull the Diagnostic Codes to see if there are any and post them here. Even codes that show up as History can be relevant, so post those as well. If you don't know how to pull codes, go here. It will tell you how. http://www.caddyinfo.com/readingcodes.html

Hi again, I have no puddle on the floor board, was not hearing the movement of water today, so hope that is fixed and I have no leaks on ground from anything or on the engine. I pulled the codes and this is what I got.

ABS C 1248,C1223,C1224

NO AMP CODES

DDM U1000,U1164

DOS U1000,U1064

DIM S1536,U1000,U1164

IPC U1000,U1164

IPM BO429,B1004

IRC U1000,U1064,U1164,U1016

LRD U1000, U1164

PCM PO465,P1599

PDM U1000,U1164

RCC U1000

NO RFA CODES

RIM CO658,U1000,U1164

RRD U1000, U1164

SDM U1040

NO VTD

Cant find where the codes are listed, so hope someone knows! Thanks for your time to help me.

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Alright. I composed a list of your codes and what they are. Most of them I am unfamiliar with, so I will let someone else explain them in detail if needed. You probably noticed that a lot of the codes were repeated through different systems but if I am not mistaken, one code = one problem, so they would all point to the same thing. Did you happen to note which codes were current and which were history by any chance?

ABS

C1248=EBCM Turned the Red Brake Warning Indicator On

C1223=Left Rear Wheel Speed Sensor Input Signal is 0

C1224=Right Rear Wheel Speed Sensor Input Signal is 0

NO AMP CODES

DDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

DOS

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

DIM

S1536 - Couldn't find this one

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPC

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPM

BO429=Temperature Control #3 Rear Circuit Range/Performance

B1004=Keep Alive Memory (KAM)

IRC

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

U1164=Loss Of DIM Serial Data Communication

U1016=Loss of Communications with PCM

LRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

PCM

PO465=Purge Flow Sensor Circuit Malfunction

P1599=Engine Stall or Near Stall Detected

PDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RCC

U1000=Class 2 Communication Malfunction

NO RFA CODES

RIM

CO658=Level Control Compressor Circuit High

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

SDM

U1040=Loss of Class 2 Communications with ABS

NO VTD

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Yes, it can be installed backwards.

I again put the front end up a hill this evening, pulled the cap off, ran the heater and fan, got antifreeze all over the place from bubbling over,

That COULD be from running the engine too long with the cap off. With the cap on, the system gets pressurized, which raises the coolants boiling point to about 265 degrees. With the cap off, a 50/50 mixture will boil at about 225 (I think). You can only run it for 5 minutes or so without the cap before it boils over. If it happened right after start up with a cold engine, then it is "false boiling" caused by exhaust gases in the cooling system pushing the coolant out. Have the block test done and good luck. Keep us advised.

Thanks Ranger and the rest of you, I had read to get the air out of the lines, run it(with heater and fan on high) till it reaches normal temp and all spitting and bubbles go out, or fans come on, about 20-30 minutes. It was a COLD start, took a good 15 min or more to get to normal temp, then it would spit the coolant somewhat in the air and over the edge then stopped and started doing it again over and over. It never went over the normal temp. Then after maybe 20 min and it settled down somewhat, I shut it off, refilled the tank. At least if it didnt get all the air out, it stopped the sound of water in the heater area. YEAH! I am planning on having the block test done in the AM, radiator shop can do it and maybe he can see if there is junk in the radiator also, it probably is due to be cleaned. Drove the car today around town with AIR off, and it behaved, no high temp, stayed at normal (half on gauge), am too freaked out to try it out on hiway with AC on. It just made me tired watching the gauge. LOL

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Alright. I composed a list of your codes and what they are. Most of them I am unfamiliar with, so I will let someone else explain them in detail if needed. You probably noticed that a lot of the codes were repeated through different systems but if I am not mistaken, one code = one problem, so they would all point to the same thing. Did you happen to note which codes were current and which were history by any chance?

ABS

C1248=EBCM Turned the Red Brake Warning Indicator On

C1223=Left Rear Wheel Speed Sensor Input Signal is 0

C1224=Right Rear Wheel Speed Sensor Input Signal is 0

NO AMP CODES

DDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

DOS

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

DIM

S1536 - Couldn't find this one

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPC

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPM

BO429=Temperature Control #3 Rear Circuit Range/Performance

B1004=Keep Alive Memory (KAM)

IRC

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

U1164=Loss Of DIM Serial Data Communication

U1016=Loss of Communications with PCM

LRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

PCM

PO465=Purge Flow Sensor Circuit Malfunction

P1599=Engine Stall or Near Stall Detected

PDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RCC

U1000=Class 2 Communication Malfunction

NO RFA CODES

RIM

CO658=Level Control Compressor Circuit High

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

SDM

U1040=Loss of Class 2 Communications with ABS

NO VTD

Thanks, I had to read them so fast and write too, but if I am not mistaking they all were HISTORY, dont remember current at all. However the PO465 makes me wonder if the purge malfunction may have kept it from getting the air out of the lines, after the water pump, thermostat, coolant heat sensor and cap was replaced, like some posts say the Northstar is self purging? So could this be a reason it is overheating due to trapped air somewhere. AND if the thermostat can be put on backwards, I asked when it was done if they put it on right and the reply was "there is only one way to put it on" makes me wonder, and if it is what would that cause? Air trapped under it? Can you tell I am trying so hard not to have to deal with it being the HG?

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Alright. I composed a list of your codes and what they are. Most of them I am unfamiliar with, so I will let someone else explain them in detail if needed. You probably noticed that a lot of the codes were repeated through different systems but if I am not mistaken, one code = one problem, so they would all point to the same thing. Did you happen to note which codes were current and which were history by any chance?

ABS

C1248=EBCM Turned the Red Brake Warning Indicator On

C1223=Left Rear Wheel Speed Sensor Input Signal is 0

C1224=Right Rear Wheel Speed Sensor Input Signal is 0

NO AMP CODES

DDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

DOS

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

DIM

S1536 - Couldn't find this one

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPC

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPM

BO429=Temperature Control #3 Rear Circuit Range/Performance

B1004=Keep Alive Memory (KAM)

IRC

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

U1164=Loss Of DIM Serial Data Communication

U1016=Loss of Communications with PCM

LRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

PCM

PO465=Purge Flow Sensor Circuit Malfunction

P1599=Engine Stall or Near Stall Detected

PDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RCC

U1000=Class 2 Communication Malfunction

NO RFA CODES

RIM

CO658=Level Control Compressor Circuit High

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

SDM

U1040=Loss of Class 2 Communications with ABS

NO VTD

Thanks, I had to read them so fast and write too, but if I am not mistaking they all were HISTORY, dont remember current at all. However the PO465 makes me wonder if the purge malfunction may have kept it from getting the air out of the lines, after the water pump, thermostat, coolant heat sensor and cap was replaced, like some posts say the Northstar is self purging? So could this be a reason it is overheating due to trapped air somewhere. AND if the thermostat can be put on backwards, I asked when it was done if they put it on right and the reply was "there is only one way to put it on" makes me wonder, and if it is what would that cause? Air trapped under it? Can you tell I am trying so hard not to have to deal with it being the HG?

I believe the purge flow sensor that the p0465 refers to has to do with the EVAP canister purge valve, which is emissions related, not coolant. I could be wrong.

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OK cowgirl, the Northstar IS self purging and if the purge line is clogged, it can overheat. All that is needed to clear any air in the system after a coolant change is rev the engine to about 3k a few times. Checking the purge line is very easy. It's the 3/8" line that is attached to the side of the surge tank near the top. Disconnect it (engine cold) and hold it in the open surge tank (to avoid a mess) and have someone start the engine. If it is clear, it should spit coolant and the flow should increase with RPM. If nothing comes out, then you need to remove that line and clear the obstruction. It's usually at the mountint point at the other end (a hollow bolt).

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Alright. I composed a list of your codes and what they are. Most of them I am unfamiliar with, so I will let someone else explain them in detail if needed. You probably noticed that a lot of the codes were repeated through different systems but if I am not mistaken, one code = one problem, so they would all point to the same thing. Did you happen to note which codes were current and which were history by any chance?

ABS

C1248=EBCM Turned the Red Brake Warning Indicator On

C1223=Left Rear Wheel Speed Sensor Input Signal is 0

C1224=Right Rear Wheel Speed Sensor Input Signal is 0

NO AMP CODES

DDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

DOS

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

DIM

S1536 - Couldn't find this one

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPC

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

IPM

BO429=Temperature Control #3 Rear Circuit Range/Performance

B1004=Keep Alive Memory (KAM)

IRC

U1000=Class 2 Communication Malfunction

U1064=Loss of Communications with DIM

U1164=Loss Of DIM Serial Data Communication

U1016=Loss of Communications with PCM

LRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

PCM

PO465=Purge Flow Sensor Circuit Malfunction

P1599=Engine Stall or Near Stall Detected

PDM

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RCC

U1000=Class 2 Communication Malfunction

NO RFA CODES

RIM

CO658=Level Control Compressor Circuit High

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

RRD

U1000=Class 2 Communication Malfunction

U1164=Loss Of DIM Serial Data Communication

SDM

U1040=Loss of Class 2 Communications with ABS

NO VTD

Thanks, I had to read them so fast and write too, but if I am not mistaking they all were HISTORY, dont remember current at all. However the PO465 makes me wonder if the purge malfunction may have kept it from getting the air out of the lines, after the water pump, thermostat, coolant heat sensor and cap was replaced, like some posts say the Northstar is self purging? So could this be a reason it is overheating due to trapped air somewhere. AND if the thermostat can be put on backwards, I asked when it was done if they put it on right and the reply was "there is only one way to put it on" makes me wonder, and if it is what would that cause? Air trapped under it? Can you tell I am trying so hard not to have to deal with it being the HG?

Read codes again, all 1000 were currect and only one more was current the IPM Bo429.

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There are so many (too many) coolant temperature variables posted in this thread that I have been reluctant to add to the confusion.

So far I read that the engine has been "pulled and gone thru 3 or 4 years ago". What does "gone thru" mean if you have the documentation?

Far too many cooling system components have been replaced with a prayer that will cure your problem. Unlikely outcome. Systematic diagnosis will identify the source of the overheating / noise in the dash.

You report the engine cooling system (air) purge line is flowing coolant. That is a good sign.

What is not so good is the inference that your engine cooling system operation has been monitored and/or observed with the pressure cap removed. Your cooling system (and most other modern engine cooling systems) is designed/intended to increase the atmospheric pressure to raise the boiling point (vaporization temperature) of the coolant mixture as required. Exactly like the physics behind "pressure cookers" that were popular several decades ago. Increasing the atmospheric pressure will raise the boiling point of a liquid (Jr HS physics).

When adjusting the engine coolant level in the cooling system reservoir, it can be necessary to suffer through 3 or 4 engine heat up / cool down to ambient temperature cycles before you reach a "stable" coolant level in the reservoir.

If your upper and lower engine plastic air flow panels are not in place, you can expect to see more engine temperature guage "activity" or excursions.

And engine cooling system symptoms is one example of when DTCs (codes) will not tell you anything you don't already know. That is, if you are paying attention to the DIC.

The single most important question/answer would be, what does "pulled and gone thru 3 or 4 years ago" really mean?

End of added confusion.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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I am sorry Jim about the confusion :fighting0025: but hopefully with information given by good people, this caddy can be back to pleasure riding without fear.

I posted why the engine was pulled, I only have the sellers info on that and my son, mechanic on heavy equip, knew when it was done and by whom. It was one of the best companies here and carries a great reputation. (however everyone can make mistakes, so hoping this one is not a result of that) But will add it was gone thru, as I call it, motor was pulled for an oil leak, all new gaskets, seals and whatever he found to be wrong. That is all I know.

Thanks Jim for your imput. Now I am little confused about your post, you mentioned the good on the purge line, then went to the cap off and I got lost as to what the results you thought may be on that. I am not

a pro on these things, as you may already have seen, so would you be kind enough to explain.

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We still don't know if "All new gaskets and seals" includes headgaskets. If the engine was pulled for an oil leak, I doubt the heads were touched but who knows???

If the headgaskets were not touched, it is possible the headgaskets are bad. If the heads were pulled and the headbolt holes were not Timeserted, it's possible the bolts have pulled.

You need to have a radiator shop test the coolant for combustion gases. Another method is to pressurize each cylinder with 120 psi shop air while the respective cylinders are at top dead center on the compression stroke and watch the surge tank for bubbling/gurgling.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I am sorry Jim about the confusion :fighting0025: but hopefully with information given by good people, this caddy can be back to pleasure riding without fear.

I posted why the engine was pulled, I only have the sellers info on that and my son, mechanic on heavy equip, knew when it was done and by whom. It was one of the best companies here and carries a great reputation. (however everyone can make mistakes, so hoping this one is not a result of that) But will add it was gone thru, as I call it, motor was pulled for an oil leak, all new gaskets, seals and whatever he found to be wrong. That is all I know.

Thanks Jim for your imput. Now I am little confused about your post, you mentioned the good on the purge line, then went to the cap off and I got lost as to what the results you thought may be on that. I am not

a pro on these things, as you may already have seen, so would you be kind enough to explain.

It seems like you know "WHAT COMPANY" did the work on the car.

Would it be possible to call them and see if they can pull the records and see what was actually done to it at that time?

As Kevin said...If the engine was pulled for an oil leak...it is not likely that the head gaskets were done.

Next step would be for a combustion by-products test to be done.

You can do it yourself or have a radiator shop do it.

That will either confirm or eliminate the head gaskets from the equation.

"THEN" we can maybe figure out what the real problem is... and get it fixed.

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I have found that if you do have a bad head gasket that you can smell it, in your coolant tank. When the engine is cool, take the cap off the coolant tank, and stick your nose in and take a smell, if you smell exhaust fumes, its a bad head gasket. As Jim noted you can have a test done by a radiator shop or you can get the NAPA test kit, but sometimes the smell test is clear

Also, does your car misfire on start up and then the misfire goes away?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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It doesnt have any misfire, sometimes the idle is not perfect, but that was normal before this....

Now I am letting it cool down and heading for the SMELLING test.

I havent found a shop yet that does the tests, but I am still trying, surely someone does them.

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