Radiator Flush

[BodybyFisher]

If a relay began to smoke, check for DTC codes, see the bottom of this post by me, follow the link to checking DTC codes, follow the directions for your year, and write down the DTC codes that come up. Your Caddy had an on board diagnostic computer and you can extract the codes, you do not need a code reader. Extract and post your codes here

[KHE]

Make sure the coolant level is at the proper point in the surge tank - 2-1/2" below the neck. If it is overfilled, it will puke out of the overflow tube.

The upper hose that connects to the surge tank near the filler neck is the purge line. Disconnect it and have someone start the engine. Coolant should flow out the hose, if not, there is a blockage.

[MarkE]

When it "burped out coolant" did the apparent coolant come out under the car, or out the exhaust, or could your wife tell? I'm assuming that you are getting steam bubbles and coolant is coming out the overflow hose on the coolant tank, which would come out under the car on the passenger side.

Another thing to smell is the exhaust, for coolant. Start the cir first thin in the morning, let it run for a few seconds, shut it down, and walk around and see of the exhaust smells of coolant. If so, you almost certainly have head leakage. If not, and if the surge tank does hot have an exhaust smell, you are very unlikely to have compression leakage.

It burped out under the car on the passenger side. I will check the smells. Thnx.

[MarkE]

If a relay began to smoke, check for DTC codes, see the bottom of this post by me, follow the link to checking DTC codes, follow the directions for your year, and write down the DTC codes that come up. Your Caddy had an on board diagnostic computer and you can extract the codes, you do not need a code reader. Extract and post your codes here

Before all of this I used my code reader and got the following codes: P0113, P0340, and P1660. The P1660 is why I changed the fuse to see if the fans would turn on. They have not turned on by themselves at all yet. I have taken both fans out and used jumper wires to confirm that they work. The code says cooling fan circuit so that is also why I was going to check the relays.

[Cadillac Jim]

If a relay smokes, it's very probably done. Unless the wiring or a fan is shorted, the problem is likely in the relay itself - shorted windings; the only other possibility is a shorted fan, which would blow the fuse, possibly before it burnt out a relay. If the fuse you replace was popped, then the short probably blew the new fuse. It's time to check the fan wiring for breaks and shorts and also the fans and relays.

The other two codes are odd. If they are CURRENT, you need to address them soon. If they are HISTORY, then one way to check whether they are real or "car wash" codes or some such is to clear them and see if they come back. You can do this after you fix the cooling fan issue.

[BodybyFisher]

See this link on P1660, lots of info for you to review, Mike

http://caddyinfo.ipbhost.com/index.php?showtopic=18391&st=15&p=129555&hl=p1660&fromsearch=1entry129555

[BodybyFisher]

Here is a photo of the 'bolt with a hole in it". You asked a question about it on another thread. I told you to check it in post #21 here. My post was clear, if you have questions ASK THEM, DON'T IGNORE STATEMENTS MADE HERE. As you saw in the other thread, a clogged bolt with a hole in it will cause overheating.

DO NOT BLOW IT OUT, REMOVE THE HOSE, AND THEN REMOVE THE BOLT (15 MM) SEE IF IT IS CLOGGED, IF IT IS CLEAR IT. REPORT BACK WHAT YOU FIND.

FOR FUTURE REFERENCE YOU NEED TO BE MORE ORGANIZED AND METHODICAL IN YOUR DESCRIPTION OF THE PROBLEM AND IN FOLLOWING AND UNDERSTANDING THE RECOMMENDATIONS GIVEN HERE. WE HAVE BEEN DOING THIS A LONG TIME 10+ YEARS, WE HAVE SEEN OVERHEATING OVER AND OVER. I HAVE PERSONALLY FIXED ABOUT 5 NORTHSTARS DUE TO CLOGGED PURGE LINES.

THE BOLT IS CIRCLED IN THIS PHOTO FOR A 98, ITS NEAR THE THROTTLE BODYAND PART OF THE THROTTLE BODY PREHEATER TO STOP ICING

[MarkE]

Here is a photo of the 'bolt with a hole in it". You asked a question about it on another thread. I told you to check it in post #21 here. My post was clear, if you have questions ASK THEM, DON'T IGNORE STATEMENTS MADE HERE. As you saw in the other thread, a clogged bolt with a hole in it will cause overheating.

DO NOT BLOW IT OUT, REMOVE THE HOSE, AND THEN REMOVE THE BOLT (15 MM) SEE IF IT IS CLOGGED, IF IT IS CLEAR IT. REPORT BACK WHAT YOU FIND.

FOR FUTURE REFERENCE YOU NEED TO BE MORE ORGANIZED AND METHODICAL IN YOUR DESCRIPTION OF THE PROBLEM AND IN FOLLOWING AND UNDERSTANDING THE RECOMMENDATIONS GIVEN HERE. WE HAVE BEEN DOING THIS A LONG TIME 10+ YEARS, WE HAVE SEEN OVERHEATING OVER AND OVER. I HAVE PERSONALLY FIXED ABOUT 5 NORTHSTARS DUE TO CLOGGED PURGE LINES.

THE BOLT IS CIRCLED IN THIS PHOTO FOR A 98, ITS NEAR THE THROTTLE BODYAND PART OF THE THROTTLE BODY PREHEATER TO STOP ICING

I am sorry for what you feel is a slipshod effort. I read these strings and new ideas to fix my problem come up. I really respect your opinion and help but do not appreciate being yelled at with all caps. I am just trying to fix a car for the mother of a Marine Iraqi Freedom Veteran!!

[BodybyFisher]

Please don't get off topic with the veteran comment to make yourself a victim, it won't win you any points here.

Yelling, yes, I am yelling you have been very disorganized and it wastes all of our time.

Sorry for getting upset, diagnosis is a very organized methodical process, there is no room for working in the dark or for being disorganized.

Fix the P1660, do a search here we have lots of info on it, I have posted schematics for it, let us know if you cant find it

[Cadillac Jim]

If you have a P1660 CURRENT and overheating, doing anything other than fixing the fans, relays, and related wiring is a waste of time.

[BodybyFisher]

True Jim, he definately needs to fix that P1660, I sent him to a site that shows info on P1660 and he MUST fix that. I have a thread on the P1660 that has schematics included someplace Ill search for it. If you go to the link above that I directed him to for the P1660, you will see how the PURGE LINE came up all of a sudden out of NO WHERE. I like to think that I have patience, but SOMETIMES some threads just put me over the edge.

But what he also missed in his initial diagnosis was checking the purge line. This is a 5 minute job that he also MUST check, not checking it is suicidal. But yes, the P1660 and the reasoning for the smoking relay is paramount.

The problem is that this thread has not gone smoothly, we are finding out things after the fact and out of sequence.

This member originally came here looking for instructions on how to FLUSH his engine, we go through time on FLUSHING/NOT FLUSHING, then we find out in post #15 that he may have a blown head gasket?, then overheating, then we find out about P1660 and then we find out the relay is smoking, and then the air purge line was not checked after checking it was recommended earlier in the thread. Next I expect to hear that straight water is being used or the system is not holding pressure. As methodical as I am with diagnosis, this thread is the antithesis of my style and its frustrating.

This thread is a classic thread of a lack of communication.

Mark PLEASE dont take that personally, but this thread has been poor in terms of communication. The Northstar is VERY different than ANY engine you or I have ever worked on. A simple clogged air purge line will cause it to retain air and the water pump will cavitate causing overheating. I rebuilt my first engine when I was in high school in 1971 it was a 426 cu in Cadillac that was burning oil. I worked in a ship yard as a mechanic working on cranes, pumps, hydraulics, yard vehicles and considered myself to be a good mechanic. In spite of that, I had to re-learn EVERYTHING including how to tighten a bolt when it came to the Northstar. I realize that you are down the road with the diagnosis and work that you have done, and got to a point of flushing the engine before focusing on P1660, purge line, etc, but it might be best to post exactly what you have and have not done to this point to refocus this thread.

[MarkE]

True Jim, he definately needs to fix that P1660, I sent him to a site that shows info on P1660 and he MUST fix that. I have a thread on the P1660 that has schematics included someplace Ill search for it. If you go to the link above that I directed him to for the P1660, you will see how the PURGE LINE came up all of a sudden out of NO WHERE. I like to think that I have patience, but SOMETIMES some threads just put me over the edge.

But what he also missed in his initial diagnosis was checking the purge line. This is a 5 minute job that he also MUST check, not checking it is suicidal. But yes, the P1660 and the reasoning for the smoking relay is paramount.

The problem is that this thread has not gone smoothly, we are finding out things after the fact and out of sequence.

This member originally came here looking for instructions on how to FLUSH his engine, we go through time on FLUSHING/NOT FLUSHING, then we find out in post #15 that he may have a blown head gasket?, then overheating, then we find out about P1660 and then we find out the relay is smoking, and then the air purge line was not checked after checking it was recommended earlier in the thread. Next I expect to hear that straight water is being used or the system is not holding pressure. As methodical as I am with diagnosis, this thread is the antithesis of my style and its frustrating.

This thread is a classic thread of a lack of communication.

Mark PLEASE dont take that personally, but this thread has been poor in terms of communication. The Northstar is VERY different than ANY engine you or I have ever worked on. A simple clogged air purge line will cause it to retain air and the water pump will cavitate causing overheating. I rebuilt my first engine when I was in high school in 1971 it was a 426 cu in Cadillac that was burning oil. I worked in a ship yard as a mechanic working on cranes, pumps, hydraulics, yard vehicles and considered myself to be a good mechanic. In spite of that, I had to re-learn EVERYTHING including how to tighten a bolt when it came to the Northstar. I realize that you are down the road with the diagnosis and work that you have done, and got to a point of flushing the engine before focusing on P1660, purge line, etc, but it might be best to post exactly what you have and have not done to this point to refocus this thread.

Thank you. I do apprecitate your help and your expertise. At times I am a little overwhelmed becasue I read so many different things that could be causing the overheating and I really hope it is not a head gasket. I have the new relay and am waiting for the pigtail since it got melted when the relay failed. Should I start a new thread for the 1660 issue? I have read your posts and am still not 100% sure as to what to do. Thank you for your patience.

[BodybyFisher]

Please post your symptoms, and what you have done so far so we can get to a starting point, I'd love for other members to chime in here but we are too out of focus. Try to address all my questions and concerns, we have VERY experienced members that have had your problems, if we can make it clear that will help

Have you found schematics for P1660?, that I may have posted?

You said you hot wired the cooling fans, explain in detail how you did that. Did you at any point hot wire the fans without disconnecting the connector?

When did the relay burn up? Was that before or after you had the cooling fans out?

Were any fuses blown? which ones

Did the fans test good?, do they run fast?, or are they dragging?

I would do testing on the wires before I plugged in a new relay, they just dont burn up for no reason,

[MarkE]

Please post your symptoms, and what you have done so far so we can get to a starting point, I'd love for other members to chime in here but we are too out of focus. Try to address all my questions and concerns, we have VERY experienced members that have had your problems, if we can make it clear that will help

Have you found schematics for P1660?, that I may have posted?

You said you hot wired the cooling fans, explain in detail how you did that. Did you at any point hot wire the fans without disconnecting the connector?

When did the relay burn up? Was that before or after you had the cooling fans out?

Were any fuses blown? which ones

Did the fans test good?, do they run fast?, or are they dragging?

I would do testing on the wires before I plugged in a new relay, they just dont burn up for no reason,

Thank you again for being patient with me. To this point my problem was the temp guage going from midline to near the red zone while driving and then going back to the mid point after burping coolant. I have read enough about NorthStars blowing head gaskets and hope that is not my case. I have read as much as I can to see why my car is doing this. I have replaced the radiator hoses, the thermostat, the water pump, and the water pump belt. My code reader did show a P1660 so I thought the A/C fuse may be bad. When I replaced the 10amp fuse for the fan it turned on without the keys in the ignition. It ran up and down in RPM and then I heard a tick. That is when the relay in the middle of the three by the radiator started to smoke. The relay melted internally and out it's side.

I tested both fans by running jumper wires from the battery to that fan motor with the fan out of the car.

[BodybyFisher]

OK check that fuse again for the AC, I believe it also controls the cooling fans

It is possible that the relay was bad, when you replaced the fuse, the relay burned up but it very surprising that, the fuse did not blow immediately and the relay smoked and melted the connector, very odd that would happen.

Did you use the same amperage fuse that was in there?, I think its 10 amps

I would replace the relay, repair the wiring and see what happens. Make sure you solder and shrink wrap the connections at the relay, it is subject to lots of dampness and water.

The temp spikes could be the fan not turning on. I would also pull the 'bolt with the hole in it' and have a look

Make sure the coolant is at least 50/50

[MarkE]

OK check that fuse again for the AC, I believe it also controls the cooling fans

It is possible that the relay was bad, when you replaced the fuse, the relay burned up but it very surprising that, the fuse did not blow immediately and the relay smoked and melted the connector, very odd that would happen.

Did you use the same amperage fuse that was in there?, I think its 10 amps

I would replace the relay, repair the wiring and see what happens. Make sure you solder and shrink wrap the connections at the relay, it is subject to lots of dampness and wat

er.

The temp spikes could be the fan not turning on. I would also pull the 'bolt with the hole in it' and have a look

Make sure the coolant is at least 50/50

Thank you very much for the help. I will try this and let you know.

[MarkE]

OK check that fuse again for the AC, I believe it also controls the cooling fans

It is possible that the relay was bad, when you replaced the fuse, the relay burned up but it very surprising that, the fuse did not blow immediately and the relay smoked and melted the connector, very odd that would happen.

Did you use the same amperage fuse that was in there?, I think its 10 amps

I would replace the relay, repair the wiring and see what happens. Make sure you solder and shrink wrap the connections at the relay, it is subject to lots of dampness and wat

er.

The temp spikes could be the fan not turning on. I would also pull the 'bolt with the hole in it' and have a look

Make sure the coolant is at least 50/50

I replaced the relay today and the pig tail and sealed them with shrink wrap. I checked the 10amp fuse and it had blown so I put a new one in. I put everything back together and ran it at idle for over twenty minutes and the fans did not turn on. I used my code reader and the P1660 is gone and the camshaft position sensor is still showing. I also now got a message on the dash that said low refrigerant. I tried to put more in but I think it went in and the A/C clutch never kicked in. Could the A/C relay in the fuse panel be bad? After the idling for twenty minutes my code reader said the coolant temp was 198F. The temp guage in the car only got just past the midway point on the dash guage. The upper has doesn't feel like is has any pressure in it while the car is running even though it is hot. I also checked the bolt with a hole and it appeared clear but i still ran an eigth inch drill bit though it with my fingers. Sorry to throw all this at you but I am trying to let you know what I have done and what my symptoms are. What do you think I should do next to get those fans to run?

Thank you very much for the help. I will try this and let you know.

[BodybyFisher]

That is great news, it sounds like you solved the P1660. With the AC off, the fans won't come on till 226, so you probably did not get there. Keep an eye on it, go for a bumper to bumper ride and see if they come on.

I didnt know you had a cam sensor code, what code is it?

Check your coolant tank cap, make sure it is good and that it holds pressure, while the engine is cool and off, squeeze the upper hose and listen at the tank to see if the system is open to the overflow, you can even pull the hose off the overflow and see if it exhausts air when you squeeze the upper hose. We have seen bad caps not build up pressure.

Your system should build up pressure when its driven at normal operating temps

[MarkE]

That is great news, it sounds like you solved the P1660. With the AC off, the fans won't come on till 226, so you probably did not get there. Keep an eye on it, go for a bumper to bumper ride and see if they come on.

I didnt know you had a cam sensor code, what code is it?

Check your coolant tank cap, make sure it is good and that it holds pressure, while the engine is cool and off, squeeze the upper hose and listen at the tank to see if the system is open to the overflow, you can even pull the hose off the overflow and see if it exhausts air when you squeeze the upper hose. We have seen bad caps not build up pressure.

Your system should build up pressure when its driven at normal operating temps

I wasn't worried about the camshaft code because it was running fine and I wanted get the overheating figured out. Was that a bad idea? The code I get is P0340.

I put a new radiator cap on yesterday when I put everything back together. I used new 50/50 dexcool. Should I check the flow of the small hose that comes off the per side of the surge tank?

I will drive it and see what happens.

[Cadillac Jim]

There is no such thing as a good code. Some codes are information-only, some indicate an intermittent or occasional problem that won't affect safety or emissions and can be ignored for the time being or perhaps indefinitely, such as an untraceable U1255 every few months. I think what BBF meant was that you had a code that means that you have a bad cam sensor signal, or had one at one time. Cam sensor signal problems can cause the spark to get confused and stop sending spark signals to the coils, although that is rare. Crank sensors have a more immediate effect, but a cam sensor HISTORY code with no driveability problems is a warning to find the problem. Check the wiring and connectors first because that is the source of most codes, not sensors themselves. The crank and cam sensors on the 1998 model year Northstars don't give trouble often.

[MarkE]

That is great news, it sounds like you solved the P1660. With the AC off, the fans won't come on till 226, so you probably did not get there. Keep an eye on it, go for a bumper to bumper ride and see if they come on.

I didnt know you had a cam sensor code, what code is it?

Check your coolant tank cap, make sure it is good and that it holds pressure, while the engine is cool and off, squeeze the upper hose and listen at the tank to see if the system is open to the overflow, you can even pull the hose off the overflow and see if it exhausts air when you squeeze the upper hose. We have seen bad caps not build up pressure.

Your system should build up pressure when its driven at normal operating temps

I wasn't worried about the camshaft code because it was running fine and I wanted get the overheating figured out. Was that a bad idea? The code I get is P0340.

I just drove the car for about six miles up and down hills. The temp guage was in the middle except right before I got home. The good news is that both fans were running and the system was pressurized. I then tried to check the DTC to see what it was telling me. I used your link to write down the step by step instructions. I can't seem to figure out which button is the "on/off" to press simultaniously with the information button. I was going to clear the low refrigerant code to hopefully let the compressor clucth engage and take in freon.

Any help is greatly appreciated.

I put a new radiator cap on yesterday when I put everything back together. I used new 50/50 dexcool. Should I check the flow of the small hose that comes off the per side of the surge tank?

I will drive it and see what happens.

[MarkE]

That is great news, it sounds like you solved the P1660. With the AC off, the fans won't come on till 226, so you probably did not get there. Keep an eye on it, go for a bumper to bumper ride and see if they come on.

I didnt know you had a cam sensor code, what code is it?

Check your coolant tank cap, make sure it is good and that it holds pressure, while the engine is cool and off, squeeze the upper hose and listen at the tank to see if the system is open to the overflow, you can even pull the hose off the overflow and see if it exhausts air when you squeeze the upper hose. We have seen bad caps not build up pressure.

Your system should build up pressure when its driven at normal operating temps

I wasn't worried about the camshaft code because it was running fine and I wanted get the overheating figured out. Was that a bad idea? The code I get is P0340.

I just drove the car for about six miles up and down hills. The temp guage was in the middle except right before I got home. The good news is that both fans were running and the system was pressurized. I then tried to check the DTC to see what it was telling me. I used your link to write down the step by step instructions. I can't seem to figure out which button is the "on/off" to press simultaniously with the information button. I was going to clear the low refrigerant code to hopefully let the compressor clucth engage and take in freon.

Any help is greatly appreciated.

I put a new radiator cap on yesterday when I put everything back together. I used new 50/50 dexcool. Should I check the flow of the small hose that comes off the per side of the surge tank?

I will drive it and see what happens.

I did drive it for about six miles up and down hills. The temp guage stayed in the middle until right before I came home. At that time it moved very close to the red zone. When I got home both fans were running and the upper hose had pressure in it. Is the temp supposed to vary that much? Should I check the purge line that comes off of the side of the coolant tank?

[Ranger]

Yes, check the purge line. If it is clear and flows coolant get the block test kit and run the test.

[MarkE]

Yes, check the purge line. If it is clear and flows coolant get the block test kit and run the test.

I checked the purge line and it is clear.

[Ranger]

Then do the block test.