atoyota4x4 post here about your overheating

I remember your original posts about overheating. Give us a recap of what you have done and what the dealer and the cooling expert may think, if you don't mind.

Have you check for trash in between the condensor and the radiator? Any bent fins on the front of the radiator? I know you have replaced some parts so sorry if I forgot if you replaced the radiator or not. I'm very interested in helping you get to the bottom of this. I'm gonna ask some people I know and see what they think.:naughty:

Well, I will try and keep this as short as possible. We purchased our 2000 Intrigue in November of 2004. That December I noticed the temp gauge acting funny on a small road trip one night. Read online about GM having a redesign on the thermostat. I replaced it with the new GM part number and all was fine up until this past 06-07 winter here in Kentucky. When the temp dropped below freezing the thing would climb to the "H".

My wife started telling me about a noise she would hear every once in a while. She said it sounded like a bag slapping underneath the car. I would drive it and could not get it to do it until one night she came home and said it did it on they way home. I immediatly got in and drove it around. Well, I soon noticed the temp gauge climbing to the "H" and when it got above 3/4 I heard "The Noise". It was a popping sound which I heard on future occasions only when it got above 3/4. I assumed this to be water hitting the hot block and vaporizing. Like a stuck thermostat or something. Anyway, she never noticed the temp gauge rising when the noise would occur. Well, the Red light on the gauge has never come on, and yes it works because I see it on start up.

So I figure its a pain in the butt to replace the thermostat but oh well, I will. I do that, but unfortunatly that did not solve the problem. So then I think its air trapped in the system. I gamble and take it to my local Valvoline Instant Oil change and have them flush the coolant, thinking this will remove any air. Well, whether it did or didn't, that did not work either. Still overheating on very cold days. Other days in the 40s or 50s, it would run normal all day long.

Next, I take it to a radiator specialist. They cannot get it to overheat, of course. because of this, they cannot try anything. So I put another T-stat on it thinking, maybe I got a bad "new" one. This time I purchase a aftermarket one. Got it in, it still would overheat.

By this time I'm ready for a trip to the dealer. Well the next morning after changing the last t-stat, I take it to my local GM dealer. On the way I notice a antifreeze smell. After about 12 miles into my trip I stop the car to check and oops, I forgot to tighten the radiator cap down. So I lost a little fluid but not much but on the way to the dealer it was overheating. I get there, tell them what the deal is and later that afternoon, I get the call from the actual mechanic. "Mr Seebold, I have driven your car over 40 miles and it has yet to over heat. Its been idling here at the shop for 1-2 hours and not once showed signs of overheating. He checked with his computer stuff and the gauge is fine and it does not indicate a blown head gasket. Oh, the radiator specialist also check for blown head gasket and they to agreed.

Well, from that time on which I believe was in late Jan or early Feb we had the same types of below freezing temps and the car did not over heat once. Unbelievable!! Did leaving the cap loose on the radiator have anything to do with it running normal up until summer? I don't know

Well, now that its gotton hot, it wants to do it again. Again, not all the time, just whenever it feels like it. I cannot tie it to anything in the world. Sometimes the A/C makes it run hot. Shut that off, it will drop back to normal, then it might get hot again with that off. Once on a recent trip in 90 degree weather it started running hot with the A/C on. I told my wife, I'm not shutting it off and if it blows up, it blows up. Well it ran hot (when I say hot, I mean between 1/2 and 3/4) for a while and then started running normal. I have no idea why.

All the fans work at the appropriate times, it has the right amount of coolant and I cannot find anything obstructing air flow.

I would love to find the answer to this mystery. I have found multiple people that experienced this same exact problem on their 3.5L, but they never said what the end result was that was causing it. Guess they would just trade it in or sell it.

At this point, I game to try anything as long as its not exspensive.

Have you ever replaced the coolant temperature sensor? Perhaps its giving you some funky readings from time to time?

atoyota4x4: I found this post on another forum. It appears that this overheating problem is causing a lot of headaches with Inttrigue owners. Not sure if you tried it but considering how long you have been dealing with it, it might be worth a try. Based on other posts in this fourm, the noise you hear could be the coolant boiling in the manifold.

"Have two 3.5's in the family. One had overheating problems and finally figured it out. Problem was air in the system. Don't know why but the boiling sound from the heater was caused by air. The heater hoses would vibrate when the noise occured. Fix was to disconnect the heater hoses and run hoses from the engine to the coolant reservoir. Ran the engine a while like this and got a lot of air out of it. Reconnected the heater hoses and disconnected the hose from the thermostat housing to the reservoir. Put a 2' section of hose on the thermostat housing and a funnel on top. Ran the engine a few minutes while pouring water in the funnel. Put it back together and filled the reservoir up completely. Ran the engine with the cap off. Last of the air escaped. Also important to note that during all these steps, the top air bleed on the radiator has to be oppened periodically to vent air from it. When the radiator seems cold and cold air is blowing from the fans, the radiator is probably full of air. Vent is on the pass side close to the battery. According to GM, temp should run between 198 and 235F. Seems high to me but after the purging, mine ran 198 on the highway which was about a needle width below the half mark, and peaked at 228F when idling immeadiately after a highway run. It cooled back down after a few minutes of the fans on hi. 228 was about a needle width above the half mark. Prior to this, I was like many of you: changed the thermostat multiple times, temp sending unit, much cursing. The other Intrigue has never had a problem. I've had that system open before and never had a cooling problem. Something about the other that made it hard to burp!"

The air in the system is very interesting. I never had any trouble and never have had any over heating when I flushed my Dex-cool.

I know 4X4 said he had it flushed but maybe they didn't bleed it properly.

Hopefully this will be your final fix and mystery solved 4X4!

I understand the theory here but if air in the system was the cuase of my problems, I have to pose the question, why did it run from Feb-May of this year with no signs of overheating? Temp gauge stayed right where it was suppose to. Also, why would it be problematic only during real cold or hot days? Why does it run normal every once in a while on a very hot day? I to thought air was the culprit but I have a hard time believeing this is it.

Gauge and temp sensor were checked out according to the GM mechanic. Everything checked out normal. He had no idea what the cause may be.

PS - Broke my bleeder screw tabs trying to open it to see if I could get air to escape back when I was in the middle of everything. Water started coming out, which told me the radiator was full.

Atoyota4x4, I can't answer your questions. If anyone could answer these questions, all these Intrigue owners would not be having these overheating problems. This seemed to work for this owner. He faced all the frustrations that you did.

Not sure I would switch the heater hoses but use the bleeder valve. You should be able to get the tab off witha pair of pliers or at least loosen it so you can use your fingers.

Good Luck.

I understand the theory here but if air in the system was the cuase of my problems, I have to pose the question, why did it run from Feb-May of this year with no signs of overheating? Temp gauge stayed right where it was suppose to. Also, why would it be problematic only during real cold or hot days? Why does it run normal every once in a while on a very hot day? I to thought air was the culprit but I have a hard time believeing this is it.

Gauge and temp sensor were checked out according to the GM mechanic. Everything checked out normal. He had no idea what the cause may be.

Probably has to do with the cooling fans coming on or not. I've never had an overheating problem and always have the AC system "ON". This triggers the fans to come on a certain temperature, probably below the half way mark on the temperature gauge. Could be the sensor/relay that triggers the fan only works intermittently. If the AC is OFF I think the fans come on at a much higher temperature.

all this is very interesting and useful, one more question though, can somebody point me to the coolant temp sensor? where is it located?

Just wondering if you've had the head gasket checked, as they sometimes fail on the 3.5, causing overheating.

I recently had trouble with my 99 olds intrigue overheating. I replaced the water pump, thermostat. and radiator but nothing worked. I took it to a reputable repair shop and after keeping it for about 3 days they figured out that the plastic air dam on the front of the car was worn out and when the wind would hit the air dam it would flex backwards and not allow air to travel through the radiator. This would cause the car to gradually overheat. They replaced the air dam and it has been fine ever since. The air dam has to be in place because these model cars have no grille in the front to allow air flow into the radiator.

I recently had trouble with my 99 olds intrigue overheating. I replaced the water pump, thermostat. and radiator but nothing worked. I took it to a reputable repair shop and after keeping it for about 3 days they figured out that the plastic air dam on the front of the car was worn out and when the wind would hit the air dam it would flex backwards and not allow air to travel through the radiator. This would cause the car to gradually overheat. They replaced the air dam and it has been fine ever since. The air dam has to be in place because these model cars have no grille in the front to allow air flow into the radiator.

Glenn, that is good to know. I've noticed that my '99 at 98k miles is starting to run a tad hotter than it use to. I'm going to check my air dam real soon.

Gentlemen this thread is too old, if interested start a new one, thanks