Over Heating

[BodybyFisher]

If you lose heat when the stat opens you have low coolant.

Do yourself a favor and buy a combustion by products tester from NAPA and test your coolant or have it tested for by products. Overheating under load is a classic head gasket problem. Also check your water pump belt for slipping look to see if its glazed or cracked or if the tensioner is binding, a slipping belt will also cause overheating under load.

[husky125cc]

I am not sure what side of the car the tank is on the 99, on my 96 its on the passenger side.

I think the '99 is on the drivers side.

Thanks for the info....located the nipple and all was clear. However, when I have the line off, it just spits fluid out as well as air. The thermostat appears to be working correctly and it seems when it opens, I lose flow. The car has had a new water pump installed before I got to it so I'm thinking it can't be that. The car is overheating anytime a load is put on it. I've tried everything in getting all the air out even though it's supposed to be self-purging. No visible leaks anywhere....also, when the thermostat opens, I lose heat inside the compartment.

I see you ruled out HGs in your first post. What makes you rule it out as a problem?

Also, have you run your codes to see if you have anything?

Hi, thanks for the response. I ruled out the HGs for a few reasons. There is no smoke coming out the back of the exhaust, there is no milky substance inside the oil pan or dip stick, no residue in the exhaust, doesn't smell like coolant out of the exhaust and it appeared to be building pressure. I know it COULD be the HGs but I wanted to make sure of everything else before automatically assuming it was the HGs like everyone seems to do.

My brother came by yesterday and ran the OBD test with his scanner. The only code that showed up, even in the code history, is one about the memory. I can't remember the exact code right now but it wasn't anything to do with that. The reason we ran the scan is because I was trying to test the ECT without removing it. It was a bear to even locate.

[BodybyFisher]

You should test your coolant for by products, your symptom is indicative of a bad head gasket

You do not need your brothers scanner, your car has the ability to report the codes to you, go to the How To at the top of this page and read DTC Codes

[husky125cc]

If you lose heat when the stat opens you have low coolant.

Do yourself a favor and buy a combustion by products tester from NAPA and test your coolant or have it tested for by products. Overheating under load is a classic head gasket problem. Also check your water pump belt for slipping look to see if its glazed or cracked or if the tensioner is binding, a slipping belt will also cause overheating under load.

Well I took the advice of a fella who seemed to know a bit about these particular engines and filled it up from the top radiator hose. I mean this thing was filled to the brim so I know it's not lack of coolant. We checked the water pump belt yesterday and it was fine, had plenty of tension and it's a new water pump so I'm proned to think it's not that either. Really hoping it's something other than the head gaskets as the symptoms just aren't there. Really hope it isn't the timeserts either.

Thanks guys for all the help....

[dgaouette]

Someone that knows the Northstar would not tell you to fill it up at the hose, it’s just not necessary. The pump on the NS will self purge provided the bleeder hose is not plugged (somewhat common). Listen to these guys when they tell you to test for combustion products, it's quick and easy. There are several other tests you can do in place of this but it will be more work. When mine went on my 98 seville there was no noticable white smoke of milky color in the oil. The only symptom I has was a rough idle for about 3 seconds at start up and overheating on the hoighway. If you were patient you could catch a few bubbles in the cooling system. Many of us with NS engines have been in denial as you may be. Suck it up ad take the test. It is what it is!!! Good luck.

[husky125cc]

Someone that knows the Northstar would not tell you to fill it up at the hose, it’s just not necessary. The pump on the NS will self purge provided the bleeder hose is not plugged (somewhat common). Listen to these guys when they tell you to test for combustion products, it's quick and easy. There are several other tests you can do in place of this but it will be more work. When mine went on my 98 seville there was no noticable white smoke of milky color in the oil. The only symptom I has was a rough idle for about 3 seconds at start up and overheating on the hoighway. If you were patient you could catch a few bubbles in the cooling system. Many of us with NS engines have been in denial as you may be. Suck it up ad take the test. It is what it is!!! Good luck.

Just going to give it back to him and tell him to take it to the dealer. I've done all I can and was hoping it was something simple but it's been made clear on here that it's a head gasket and I'm not going that far with it. It is hunting season after all and it's already wasted a ton of my time. It holds pressure until the thermostat opens so it must be getting air locked or air in there somewhere and that points towards a a leak, which I haven't seen, or a HG issue. Thanks for trying.

Here is the guy who told me to fill from the radiator in order to try and purge this supposed self purging system.....

http://www.rxauto.com/northstar-kits.html

I called about the kit and he recommended trying that. Once again thanks for replying.

[BodybyFisher]

If you lose heat when the stat opens you have low coolant.

Do yourself a favor and buy a combustion by products tester from NAPA and test your coolant or have it tested for by products. Overheating under load is a classic head gasket problem. Also check your water pump belt for slipping look to see if its glazed or cracked or if the tensioner is binding, a slipping belt will also cause overheating under load.

Well I took the advice of a fella who seemed to know a bit about these particular engines and filled it up from the top radiator hose. I mean this thing was filled to the brim so I know it's not lack of coolant. We checked the water pump belt yesterday and it was fine, had plenty of tension and it's a new water pump so I'm proned to think it's not that either. Really hoping it's something other than the head gaskets as the symptoms just aren't there. Really hope it isn't the timeserts either.

Thanks guys for all the help....

Filling it up from the upper hose is NOT necessary at all. Where is it filled up to the brim at?, the hose? or is it at the CORRECT cold level at the TANK? The NS cooling system self purges through that PURGE line we discussed, special filling procedures are NOT necessary.

Is your cooling system holding pressure? Has a pressure test been done? Has the CAP been replaced or at least tested if possible? Is the system coolant at 50/50? Are the cooling fans working properly?

You DO have a head gasket symptom, overheating anytime a load is put on it, THAT is a HG symptom.

Explain what is happening when it 'overheats'

boilover?

temp gage high?

warning messages?

[dgaouette]

Interesting site, did you notice that they no longer guarantee the product!! This must be some good stuff, just dump it in and it automatically removes the striped out head bold and repairs the threads, then reinserts the bolt!!! Looks to me like a dump it in and trade it kind of product. If you have had an engine apart, you will realize that this is at best a temporary fix. I think the "no guarantee" spells it out.

[BodybyFisher]

Someone that knows the Northstar would not tell you to fill it up at the hose, it’s just not necessary. The pump on the NS will self purge provided the bleeder hose is not plugged (somewhat common). Listen to these guys when they tell you to test for combustion products, it's quick and easy. There are several other tests you can do in place of this but it will be more work. When mine went on my 98 seville there was no noticable white smoke of milky color in the oil. The only symptom I has was a rough idle for about 3 seconds at start up and overheating on the hoighway. If you were patient you could catch a few bubbles in the cooling system. Many of us with NS engines have been in denial as you may be. Suck it up ad take the test. It is what it is!!! Good luck.

Just going to give it back to him and tell him to take it to the dealer. I've done all I can and was hoping it was something simple but it's been made clear on here that it's a head gasket and I'm not going that far with it. It is hunting season after all and it's already wasted a ton of my time. It holds pressure until the thermostat opens so it must be getting air locked or air in there somewhere and that points towards a a leak, which I haven't seen, or a HG issue. Thanks for trying.

Here is the guy who told me to fill from the radiator in order to try and purge this supposed self purging system.....

http://www.rxauto.com/northstar-kits.html

I called about the kit and he recommended trying that. Once again thanks for replying.

PLEASE DO NOT give out MIS-INFORMATION. Stating SUPPOSED SELF PURGING SYSTEM, implies that it is NOT self purging. GET this straight, this IS a self purging system. You obviously have a problem that you have not detected yet. Spend $50 and have the coolant tested for BY PRODUCTS first, slamming the Northstar fixes NOTHING.

Diagnose and answer the questions first.

IF you have a headgasket breach, HOT combustion gases SUPERHEAT the coolant and cause spontaneous boiling, this happens at the BEGINNING of a head gasket breach, as you know the compression stroke produces +100 PSI, much higher than the 16 PSI produced by the cooling system.

SO you can have overheating LONG BEFORE you leak coolant INTO the cylinder!

WE have been seeing and diagnosing these problems for YEARS, and have seen overheating before coolant loss, steam out of the exhaust, etc.

[husky125cc]

Someone that knows the Northstar would not tell you to fill it up at the hose, it’s just not necessary. The pump on the NS will self purge provided the bleeder hose is not plugged (somewhat common). Listen to these guys when they tell you to test for combustion products, it's quick and easy. There are several other tests you can do in place of this but it will be more work. When mine went on my 98 seville there was no noticable white smoke of milky color in the oil. The only symptom I has was a rough idle for about 3 seconds at start up and overheating on the hoighway. If you were patient you could catch a few bubbles in the cooling system. Many of us with NS engines have been in denial as you may be. Suck it up ad take the test. It is what it is!!! Good luck.

Just going to give it back to him and tell him to take it to the dealer. I've done all I can and was hoping it was something simple but it's been made clear on here that it's a head gasket and I'm not going that far with it. It is hunting season after all and it's already wasted a ton of my time. It holds pressure until the thermostat opens so it must be getting air locked or air in there somewhere and that points towards a a leak, which I haven't seen, or a HG issue. Thanks for trying.

Here is the guy who told me to fill from the radiator in order to try and purge this supposed self purging system.....

http://www.rxauto.com/northstar-kits.html

I called about the kit and he recommended trying that. Once again thanks for replying.

PLEASE DO NOT give out MIS-INFORMATION. Stating SUPPOSED SELF PURGING SYSTEM, implies that it is NOT self purging. GET this straight, this IS a self purging system. You obviously have a problem that you have not detected yet. Spend $50 and have the coolant tested for BY PRODUCTS first, slamming the Northstar fixes NOTHING.

Diagnose and answer the questions first.

IF you have a headgasket breach, HOT combustion gases SUPERHEAT the coolant and cause spontaneous boiling, this happens at the BEGINNING of a head gasket breach, as you know the compression stroke produces +100 PSI, much higher than the 16 PSI produced by the cooling system.

SO you can have overheating LONG BEFORE you leak coolant INTO the cylinder!

WE have been seeing and diagnosing these problems for YEARS, and have seen overheating before coolant loss, steam out of the exhaust, etc.

Wow, you're a friendly fella. I didn't give out mis-information nor did I imply anything, I was just stating that I was told, from the person at the link I posted above, to fill from the radiator hose to purge air from a system that's supposed to be self-purging. I've found other posts on here where they tell you to take the cap off to try and release the air from the surge tank. I didn't see them get reamed for that. Not worth it to get blasted by you when I'm trying to figure this out. I understand how head gasket leaks work and I understand the combustible gases get in the lines because of it. Complicated system and I was hoping I was missing something obvious which I now know I'm not. I know I have a problem I haven't detected, hence the reason I'm here. The testing is getting done this weekend for gasses in the lines. You ought to consider understanding what was said and not take it out of context before you blow your own head gasket. Geesh. I've been really grateful for the help and have stated so. All of this for a friend to try and save him money. Guess this is what you get for trying to help.

[husky125cc]

If you lose heat when the stat opens you have low coolant.

Do yourself a favor and buy a combustion by products tester from NAPA and test your coolant or have it tested for by products. Overheating under load is a classic head gasket problem. Also check your water pump belt for slipping look to see if its glazed or cracked or if the tensioner is binding, a slipping belt will also cause overheating under load.

Well I took the advice of a fella who seemed to know a bit about these particular engines and filled it up from the top radiator hose. I mean this thing was filled to the brim so I know it's not lack of coolant. We checked the water pump belt yesterday and it was fine, had plenty of tension and it's a new water pump so I'm proned to think it's not that either. Really hoping it's something other than the head gaskets as the symptoms just aren't there. Really hope it isn't the timeserts either.

Thanks guys for all the help....

Filling it up from the upper hose is NOT necessary at all. Where is it filled up to the brim at?, the hose? or is it at the CORRECT cold level at the TANK? The NS cooling system self purges through that PURGE line we discussed, special filling procedures are NOT necessary.

Is your cooling system holding pressure? Has a pressure test been done? Has the CAP been replaced or at least tested if possible? Is the system coolant at 50/50? Are the cooling fans working properly?

You DO have a head gasket symptom, overheating anytime a load is put on it, THAT is a HG symptom.

Explain what is happening when it 'overheats'

boilover?

temp gage high?

warning messages?

Actually I've tried both, filled it up from the hose and from the surge tank.

I have replaced the cap with a new one. The old one was no good. Cooling fans are working properly, thermostat is working properly and the water pump is pumping. It's just when the thermostat opens, it loses pressure in the lines and thus the water boils and steams out. Testing for the gasses, thanks for the help. I'm thinking head gasket and I've seen on here where sometimes it'll read a false positive when the test is done. Autozone will do it for free I believe.

I saw the warranty info on the site I provided and wasn't going to purchase it after I saw that. Can't have a quick fix for a head gasket or a timesert issue. Aluminum head is good so it doesn't warp but the timeserts issue should have been addressed by Cadillac and corrected.

And Yeah, it's definitely overheating only when a load is on the motor which leads me right back to HG. Hopefully the test will confirm. I really do appreciate the help.

[BodybyFisher]

Listen, lets get something straight. As you can see, I am a LOT of help and I WILL help UNTIL statements like this

Here is the guy who told me to fill from the radiator in order to try and purge this supposed self purging system.....

That statement that YOU made DOES IN FACT IMPLY that the system is NOT self purging.

I will not allow THOSE types of statement to remain unchallenged. You have NOT been blasted and once I challenged that statement I continued helping.

I am STILL friendly and will REMAIN friendly but you need to do much more analysis and diagnosis at this point.

Do the coolant test

[husky125cc]

Listen, lets get something straight. As you can see, I am a LOT of help and I WILL help UNTIL statements like this

Here is the guy who told me to fill from the radiator in order to try and purge this supposed self purging system.....

That statement that YOU made DOES IN FACT IMPLY that the system is NOT self purging.

I will not allow THOSE types of statement to remain unchallenged. You have NOT been blasted and once I challenged that statement I continued helping.

I am STILL friendly and will REMAIN friendly but you need to do much more analysis and diagnosis at this point.

Do the coolant test

I understand and I do appreciate your assistance. My point was, why would I be told to purge a system that is self purging? That's what I mean and that's why I said supposed. Hence this sentence Here is the guy who told me to fill from the radiator in order to try and purge this supposed self purging system..... So not a big deal, just wanted you to know that I was misunderstood. I'm sure there are all kinds of discrepanices here that could fall under that category as being misunderstood. Bygones for sure.....I tend to get scrappy when challenged as obviously you do too.

[BodybyFisher]

Understood.

If you look at this thread it started a long time ago. Statements that imply or allow question will be searched by others and to leave uncertainty is problematic. I hope you understand that, its not a matter of not wanting or liking to be challenged, its wanting to set the record straight for future searchers.

Let us know how we can help and let us know how your testing turns out, Mike

[creeker]

Last Monday my 94-STS started overheating without warning. Hoses were hot, but no heat just cold air blowing. I changed the thermostat, refilled the overflow tank. Still same problem. I took it to PEP Boys, which is two blocks away, only because i thought it need to be flushed. Pep Boys refused to flush the system, because they said Anti-Freeze was leaking through the overflow tube. I only took it to Pep-Boys because i figured a bunch of monkeys can do a simple radiator flush. Any way since they would not do it. I started driving the car around the neighborhood and the problem seemed to have fixed itself. Heat started working temperature stayed between 199-208 degrees. Today started driving the car started to over heat again temp went up to 250-degrees after i parked the car, i heard the antifreeze boiling and bubbling then it started pouring out of the overflow tube. Suggestions please!!!! New Thermostat, Cap, new radiator in April, electric fans working. Do you all think i should put in a new heater core? local shop want $40.00 for new one

You should never flush a northstar engine, (with tap water) and only use dexcool antifreeze and distilled water.half and half. Drain out as much old coolant as you can (Lower engine rad. hose) and add fresh mixture.

If you have to be convinced further p.m me and I will refer you to more info.

[BodybyFisher]

Last Monday my 94-STS started overheating without warning. Hoses were hot, but no heat just cold air blowing. I changed the thermostat, refilled the overflow tank. Still same problem. I took it to PEP Boys, which is two blocks away, only because i thought it need to be flushed. Pep Boys refused to flush the system, because they said Anti-Freeze was leaking through the overflow tube. I only took it to Pep-Boys because i figured a bunch of monkeys can do a simple radiator flush. Any way since they would not do it. I started driving the car around the neighborhood and the problem seemed to have fixed itself. Heat started working temperature stayed between 199-208 degrees. Today started driving the car started to over heat again temp went up to 250-degrees after i parked the car, i heard the antifreeze boiling and bubbling then it started pouring out of the overflow tube. Suggestions please!!!! New Thermostat, Cap, new radiator in April, electric fans working. Do you all think i should put in a new heater core? local shop want $40.00 for new one

You should never flush a northstar engine, (with tap water) and only use dexcool antifreeze and distilled water.half and half. Drain out as much old coolant as you can (Lower engine rad. hose) and add fresh mixture.

If you have to be convinced further p.m me and I will refer you to more info.

You just responded to a 2005 post and I don't think he owns the car anymore

[johngo7470]

Hi All,

You guys are F_cking incrediable. Guru, your the best. OverHeat problems fixed.

Last night after work, i decided to change all the small coolant hoses. I took off the metal line that runs from the surge tank to the water pump, no blockage. I then decided to take out the hollow bolt that is in the water pump housing. There was my problem. There was a piece of hose stuck in the hole, which was blocking correct coolant and air flow. After putting new hoses on and cleaning the nipple, i drove the car around this morning for about 3-hours. In traffic the hottest it got was 205-degrees. Once i started driving it went down to 201-and stayed there. I'm going to let the car cool for a couple of hours, recheck the tank, and top off if necessary.

Thank's again guy's without your advice i would have been spending money, without solving the problem.

Thank You

Jeffrey!!!!

Add me to the list of those suffering from overheating, who read the posts here, found "the hollow bolt" blocked, and now no longer suffers overheating.

My situation was also complicated by leaks which allowed air in the system, which quite often created an airgap that prevented coolant flow when idling (like in stopped traffic or at a stoplight).

JohnG

[BodybyFisher]

Nice John, glad you found your problem!