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I have a 1998 Cadillac El Dorado that overheats at will while driving. It never overheats to the point of shut off but pushes the limits of the gauge. What I mean is out of the blue it heats up almost fully overheating and out of nowhere and cools itself off. Almost as if the fans are rescuing it. The fans are working. It has a new water pump, radiator, 50-50 radiator fluid (DexCool}. Through all of my reading I see that head gaskets may be a problem so I will test the fluid. If there are any sensors or tricks besides the purge line which I've already checked. Also I have an error code P1483 and ACM B1350 Please advise! Thank you very much. PS I'm sorry if this is in the wrong forum. I'm a newbie and am learning as I go. It seems that under help by model El Dorado doesn't have a section.

P Christopher :)

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I have a 1998 Cadillac El Dorado that overheats that will while driving. It never overheats to the point of shut off but pushes the limits of the gauge. What I mean is out of the blue it heats up almost fully overheating and out of nowhere and cools itself off. Almost as if the fans are rescuing it.

"Overheating" covers a wide range of values for an even wider range of drivers. Tell us temperatures if you can. The picture below might be of some assistance.

The fans are working. It has a new water pump, radiator, 50-50 radiator fluid (DexCool}. Through all of my reading I see that head gaskets may be a problem so I will test the fluid.

If "testing the fluid" means testing for combustion byproducts in the coolant reservoir air space, that would be a great first step. AutoZone has a device that will do just that in their rent-a-tool program. The AZ part# for the tester is 27145, and the AZ part number for the test fluid is 25739. Total cost to you is less than $10.00. Read the instructions on the tester 3 or 4 times.

If there are any sensors or tricks besides the purge line which I've already checked.
Well done on checking the purge line. You might think about checking the purge line flow several times over several days; blockages can come and go at random.
Also I have an error code P1483....
P1483 - Engine Cooling System Performance

That code is not very informative. But you are on the right track.

Don't worry about the forum, someone will move this thread to the correct page.

th_Smallertempguagewithnumbers.jpg

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Check to see if the air purge line is clogged. If it is clogged, air will be trapped in the system and the water pump will cavitate

When the engine is cool, with the engine off, gently pull the hose off the top of the coolant tank, NOT THE OVERFLOW HOSE, the other one, start the engine, coolant should flow out of the hose steadily. Let us know the result of this test

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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Thanks Jim for your reply. Thanks to this website I looked up the codes earlier. Other than logically I have no idea what the codes truly mean. I didn't know if they pointed to a specific part or what?

P Christopher :)

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The temperature gauge reads at 12 o'clock typically when all is well. After I put the new radiator in it red slightly off center of 12 o'clock. When it heats up it goes to the max. Shuts the AC off and then like a miracle cools itself back to the center.

I have a 1998 Cadillac El Dorado that overheats that will while driving. It never overheats to the point of shut off but pushes the limits of the gauge. What I mean is out of the blue it heats up almost fully overheating and out of nowhere and cools itself off. Almost as if the fans are rescuing it.

"Overheating" covers a wide range of values for an even wider range of drivers. Tell us temperatures if you can. The picture below might be of some assistance.

The fans are working. It has a new water pump, radiator, 50-50 radiator fluid (DexCool}. Through all of my reading I see that head gaskets may be a problem so I will test the fluid.

If "testing the fluid" means testing for combustion byproducts in the coolant reservoir air space, that would be a great first step. AutoZone has a device that will do just that in their rent-a-tool program. The AZ part# for the tester is 27145, and the AZ part number for the test fluid is 25739. Total cost to you is less than $10.00. Read the instructions on the tester 3 or 4 times.

If there are any sensors or tricks besides the purge line which I've already checked.
Well done on checking the purge line. You might think about checking the purge line flow several times over several days; blockages can come and go at random.
Also I have an error code P1483....
P1483 - Engine Cooling System Performance

That code is not very informative. But you are on the right track.

Don't worry about the forum, someone will move this thread to the correct page.

th_Smallertempguagewithnumbers.jpg

P Christopher :)

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Yes I've done this purge-line thing on more than one occasion. When I remove it no fluid comes out but if I blow into it it goes through the system I assume and then comes out of the overflow.

Check to see if the air purge line is clogged. If it is clogged, air will be trapped in the system and the water pump will cavitate

When the engine is cool, with the engine off, gently pull the hose off the top of the coolant tank, NOT THE OVERFLOW HOSE, the other one, start the engine, coolant should flow out of the hose steadily. Let us know the result of this test

P Christopher :)

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However I will try and do it with the engine started and get back thanks.

Yes I've done this purge-line thing on more than one occasion. When I remove it no fluid comes out but if I blow into it it goes through the system I assume and then comes out of the overflow.

Check to see if the air purge line is clogged. If it is clogged, air will be trapped in the system and the water pump will cavitate

When the engine is cool, with the engine off, gently pull the hose off the top of the coolant tank, NOT THE OVERFLOW HOSE, the other one, start the engine, coolant should flow out of the hose steadily. Let us know the result of this test

P Christopher :)

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I think you misunderstood. The purge line only flows coolant when the engine is running.

When you do the block test, you are testing the air in the surge tank for exhaust gases. You are not testing the coolant. You might even try the sniff test first. See if the surge tank smells like exhaust.

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Thanks for bringing that attention I later realized what he meant and sent him a reply. Oddly enough if you blow into the line it will put pressure through the system and come out through the overflow showing continuity or lack of blockage. But I will check the other for sure. And to give the overflow a sniff test as well ha ha. Thanks

I think you misunderstood. The purge line only flows coolant when the engine is running.

When you do the block test, you are testing the air in the surge tank for exhaust gases. You are not testing the coolant. You might even try the sniff test first. See if the surge tank smells like exhaust.

P Christopher :)

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Yes I've done this purge-line thing on more than one occasion. When I remove it no fluid comes out but if I blow into it it goes through the system I assume and then comes out of the overflow.

I'm going to assume you are checking this purge line with the engine running, as one other member has pointed out already. That being said, I remember another member that found a piece of rubber hose inside the hollow bolt where the engine end of the purge line is connected. DO NOT blow it back into the engine, but remove the bolt and check for loose particles behind that bolt. This will need to be done with the engine off and the coolant cool so it won't scald you.

Never underestimate the amount of a persons greed.

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For some reason my purge line has no bolt or easily unattachable part to get behind and unclog if necessary. Thx

Yes I've done this purge-line thing on more than one occasion. When I remove it no fluid comes out but if I blow into it it goes through the system I assume and then comes out of the overflow.

I'm going to assume you are checking this purge line with the engine running, as one other member has pointed out already. That being said, I remember another member that found a piece of rubber hose inside the hollow bolt where the engine end of the purge line is connected. DO NOT blow it back into the engine, but remove the bolt and check for loose particles behind that bolt. This will need to be done with the engine off and the coolant cool so it won't scald you.

P Christopher :)

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vvery easy. Look at the driver side dogbone motor mount. look at the small hose on the side. The hose has a squeeze clamp. Remove the hose, unscrew the bolt/fitting. (it will come out tight due to the threadlock) Check the boly and make sure it is clear. While the bolt is out start the engine and watch the flow of coolant

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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However I will try and do it with the engine started and get back thanks.

Yes I've done this purge-line thing on more than one occasion. When I remove it no fluid comes out but if I blow into it it goes through the system I assume and then comes out of the overflow.

Check to see if the air purge line is clogged. If it is clogged, air will be trapped in the system and the water pump will cavitate

When the engine is cool, with the engine off, gently pull the hose off the top of the coolant tank, NOT THE OVERFLOW HOSE, the other one, start the engine, coolant should flow out of the hose steadily. Let us know the result of this test

Yes, do that as per my directions and DO NOT blow through the line EVER, if you DO have a clog you will dislodge it and you DO NOT want to dislodge it you want to REMOVE the clog.

Let us know the outcome of the test as per my directions above and DO NOT do anything until you post and we will tell you what to do then.

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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Here is a photo of the 'bolt with a hole in it" from my 96, again DO NOT blow the line out.

IF it is clogged, remove the hose, then remove the bolt with the nipple on it and clean out the metering hole in the middle of the bolt with a drill bit or something you push through

it, the bolt is at 2 o'clock in this photo

WaterPumpandRadiator022-1.jpg

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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Thanks to all for the help. I really appreciate all of the valuable input. I am gonna tackle it further this afternoon and will report the findings so as not to leave all of the contributors hanging. Again thanks especially for the pictures.

Here is a photo of the 'bolt with a hole in it" from my 96, again DO NOT blow the line out.

IF it is clogged, remove the hose, then remove the bolt with the nipple on it and clean out the metering hole in the middle of the bolt with a drill bit or something you push through

it, the bolt is at 2 o'clock in this photo

WaterPumpandRadiator022-1.jpg

P Christopher :)

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OK the purge line had a stream similar to urine at 1st check 2nd ck it was intermittent 3rd check hot air. haven't made it to AZ yet to test the HG.

Thanks to all for the help. I really appreciate all of the valuable input. I am gonna tackle it further this afternoon and will report the findings so as not to leave all of the contributors hanging. Again thanks especially for the pictures.

Here is a photo of the 'bolt with a hole in it" from my 96, again DO NOT blow the line out.

IF it is clogged, remove the hose, then remove the bolt with the nipple on it and clean out the metering hole in the middle of the bolt with a drill bit or something you push through

it, the bolt is at 2 o'clock in this photo

WaterPumpandRadiator022-1.jpg

P Christopher :)

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I took out the purge plug or bolt with the hole in it and it wasn't clogged and all lines that are easily checked are clear.

OK the purge line had a stream similar to urine at 1st check 2nd ck it was intermittent 3rd check hot air. haven't made it to AZ yet to test the HG.

Thanks to all for the help. I really appreciate all of the valuable input. I am gonna tackle it further this afternoon and will report the findings so as not to leave all of the contributors hanging. Again thanks especially for the pictures.

Here is a photo of the 'bolt with a hole in it" from my 96, again DO NOT blow the line out.

IF it is clogged, remove the hose, then remove the bolt with the nipple on it and clean out the metering hole in the middle of the bolt with a drill bit or something you push through

it, the bolt is at 2 o'clock in this photo

WaterPumpandRadiator022-1.jpg

P Christopher :)

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I advise that you pull that bolt out, its 15mm, see if its clogged, if you were idling and you got a no stream condition, you need to look, you should get a stream.

Was the coolant level up?

Pull it and let us know, Mike

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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  • 2 weeks later...

Thanks to all who responded to my issue. As life would have it the head gasket seems to be blown. I shall pony up the $$$$$$$ for the rebuild which includes the head gaskets, valve cover gaskets, oil pan gasket, am doing some extras while it's apart like the water pump, all 3 timing chains. So in a nutshell you saw what went wrong or the symptoms, and what was done to fix it :) Thx again

P Christopher :)

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Hey there folks,

I might be risking a whipping by y'all for asking this, but I don't have a clue and am curious what's typically involved. Here is what I am being told by the mechanic he is doing, what do you think?? Replacing of the HG, all involved gaskets, rear main seal, oil pan gasket "which currently has minor leak", water pump, all fluids, oil, Dexcool etc. plus the actual labor of course. also he's changing the 3 timing chains while he's in there. I was hoping to see what details I need to be specific about so my car lasts another 117k. I have read a lot of posts with confusing details and do not want to miss any important goodies while my car is in multiple pieces. Any offerings of information are welcomed. THANKS

P Christopher :)

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Hey there folks,

I might be risking a whipping by y'all for asking this, but I don't have a clue and am curious what's typically involved. Here is what I am being told by the mechanic he is doing, what do you think?? Replacing of the HG, all involved gaskets, rear main seal, oil pan gasket "which currently has minor leak", water pump, all fluids, oil, Dexcool etc. plus the actual labor of course. also he's changing the 3 timing chains while he's in there. I was hoping to see what details I need to be specific about so my car lasts another 117k. I have read a lot of posts with confusing details and do not want to miss any important goodies while my car is in multiple pieces. Any offerings of information are welcomed. THANKS

First off, what tests were done to make sure that you have a blown head gasket? This is important, because there are things that can be wrong that can cause overheating but its not the head gasket.

What are your symptoms?

Has your mechanic done a head gasket on a Northstar before?

Why is he replacing the water pump

The timing chains DO NOT need to be changed ever, they are good for the life of the car

If you do have a bad head gasket, is he timeserting the block, or studding the block?, he can NOT do a head gasket without doing one or the other, that is VERY important

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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Assuming the diagnosis points toward the head gaskets, while the engine is out of the car, replace the oil manifold plate (it is between the oil pan and lower crankcase half and re-seal the lower crankcase.

The timing chains do not require replacement. The guides will have minor wear on them but are typically good for the life of the vehicle. New guides will get the same wear marks in 5000 miles.

One thing to check is the tensioner on the intermediate timing chain (between the crankshaft sprocket and the intermediate sprocket (where the camshaft chains are driven). Sometimes, the pad on the tensioner will wear a deep groove. If that is the case, it makes sense to replace that tensioner while the engine is apart.

When re-sealing the crankcase halves, be sure to use the GM sealant. There is NO substitute for this product.

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

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There's two VERY fundamental problems in what you posted.

First, in the last thread you started, there was a conclusion that the problem is a head gasket - but - the problem you described is not necessarily a head gasket problem.

So, did someone do a combustion by-products test on the coolant in your recovery tank?

Second, head gaskets on Northstars don't fail - it's the threads that hold the bolts that hold the head on that fail. And I don't see anything in your post about the head bolts.

If the mechanic didn't talk about either of those things, then, get your car and go somewhere else, FAST.

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your a new member. how long have you had this eldo? #1 point is take the car to an experienced northstar mechanic. for the money you will be spending. find a seasoned pro. DFW is a big place. there has to be a few mechanics that fit the bill. or bite the bullet and go to a dealer.

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