intrigue overheating!

i cant figure out whats causing my intrigue to overheat. when i first got the car a few months ago if you were sitting with the heat on it would start to overheat but when you turned the heat off it would automatically cool down. now it overheats randomly, from what i can tell the water pump is working fine so i thought it was the thermo. i removed it to see if it would stop the problem and it didnt and i havent put it back in yet. im not losing water anywhere that i can see.

the car will drive fine for a day or 2 then decide it wants to overheat. it builds up a lot of pressure, seems like its more then it should build up to the point where all the hoses are so hard you cant squeeze them. if i open the resevoir and release the pressure the car will automatically cool down and is driveable again.

does anyone know what i should try to solve the problem or how to further troubleshoot so i can get this fixed? this is starting to get annoying. thanks!!!

First, what model year Intrigue do you have, what engine and miles? Has the coolant ever been changed?

I would make sure the coolant level is where it should be. It seems like you have a blockage in the cooling system. I have read about blockages in the heater core.

sorry, i have a 2001 with a 3.5 and around 130,000 on the clock. ive flushed the system and saw no blockages. i even unhooked the 2 hoses coming from the firewall and ran water and blew thru them to make sure the heater core wasnt blocked.

right now theres water in the system instead of coolant because i didnt want to waste $30 on dex-cool and the problem wasnt fixed.

I had that problem a few years ago. I first flushed the fluid and got it all clean, still ran hot; then I changed the thermostat, still ran hot; then the waterpump, it got better, but still would get high; finally I just changed the radiator. Problem solved. There was gunk in the radiator that I couldn't flush out. I flushed it out twice, but I could not get all of the gunk out. It was just time for a new radiator I guess. Though it took changing out the entire coolant system. It didn't run hot anymore. With a set of extra eyes, it wasn't a bad project.

changing the radiator sounds easier then doing the head gaskets like people are telling me is the problem. i dont think its the head gaskets tho because there is no smoke, only a lil on the first start of the day but when it warms up there isnt any. and theres no water or coolant in the oil or it isnt burning oil.....this car has me confused.

EDIT: how do i tell if theres trash in the radiator? ive flushed it about 2-3 times now. and i love visiting warner robins, if the car wasnt giving me so many problems i would most likely drive down there in about 2 weeks instead of fly!

somebody please tell me something! some way to troubleshoot or some things to try. today the overheating got worse and this is really starting to piss me off!!! i hope im not going to have to just change out the whole coolant system. i hate this car!!!

What exactly did you do to the water pump to determine that its working fine?


Water pump problems are not completely uncommon in the 3.5 I can think of a couple cases off the top of my head. The guy who had his pump fail in the middle of a road trip springs to mind.


Could be that your WP blades are shot to heck, or something like that.


Right now RockAuto has a limited supply of water pumps for 29.99 plus shipping.

If you want to order from RockAuto go to the last page of this thread:
http://www.fatwallet.com/forums/hot-deals/370308/ There you will find a discount code, its not much, but its better than nothing.

Im curious to know how you ran it without the thermostat in it as well, as its all one piece, and the thermostat itself didnt appear removable, but I could be mistaken.

If youre refusing to take it too a mechanic, then you dont have much of a choice but to start replacing things. People have had problems in the past with WPs, much moreso than radiators, couple that with the fact it was still overheating with the thermostat completely removed, sounds like a dying water pump to me.

At the very least you could pull your existing water pump off and see what it looks like, directions dont look terribly difficult, and its not like you have any coolant to lose since you filled up with water.

I agree with LittleHoov. The water pump isn't expensive and it's better to shoot for those areas first. Me and my brother changed it in a matter of an hour. Mainly due to the tight fit of the engine. And trust me, I'm no mechanic, but with an extra set of eyes, we were able to nip it in the bud.

The gunk/sluggish material in my radiator was noticed on the radiator cap the most. I got some of it out after flushing it, but after I changed it out, we found a lot was still left in it.

changing the radiator sounds easier then doing the head gaskets like people are telling me is the problem. i dont think its the head gaskets tho because there is no smoke, only a lil on the first start of the day but when it warms up there isnt any. and theres no water or coolant in the oil or it isnt burning oil.....this car has me confused.

EDIT: how do i tell if theres trash in the radiator? ive flushed it about 2-3 times now. and i love visiting warner robins, if the car wasnt giving me so many problems i would most likely drive down there in about 2 weeks instead of fly!

It's great here, just hot as Hades!

someone looked at it for me and said the water pump was moving water fine. i dont know how they determined that but ill just take the water pump off tomorrow and see what the inside looks like and post a picture, hopefully this is the problem and its not anything more serious!

and yea it is great in warner robins, weather is better then detroits and liquor is cheaper lol. i love the scenery out there!

EDIT: anything else i should look for when i remove the water pump?

do i HAVE to use dexcool or regular coolant in my intrigue or can i use water?

do i HAVE to use dexcool or regular coolant in my intrigue or can i use water?

You could use regular green anti-freeze in it, but I would highly recommend NOT using the green stuff because the 3.5L is an all aluminum engine. I would just use the universal Prestone or Peak stuff. It's still an extended-life coolant but not as "bad" as Dexcool. All the bad talk against Dexcool is all hype IMO and it works just fine. The regular green stuff will build up electrolytes fairly quick if you leave it in there much longer than 50K miles or 3 years. Those electolytes really like to eat aluminum.

thanks ruley73, but what im really trying to ask is could it be the fact that im running water in my coolant system be the reason my car is overheating?

Have you tried to change out the thermostat? Inexpensive troubleshooting suggestion.

thanks ruley73, but what im really trying to ask is could it be the fact that im running water in my coolant system be the reason my car is overheating?

If you are running just straight water in there right now that is definitely why it is overheating. Antifreeze lowers the freezing point, but also raises the boiling point. I would also have your coolant cap pressure tested or just replace it (cheap ~$5). The pressure the cap holds also raises the boiling point.

Water in liquid form can only reach 212*F under no pressure at sea level. However, steam (obviously this is vaporized water) can get as hot as the enviroment permits.

If the system is pressurizing properly running water shouldnt matter. Pressurizing the system increases the boiling point of water, I dont know the math on it. But I know it does.

Your Intrigue should be running below 212 anyway unless youre sitting still perhaps. Even then with the AC on your fans should already be running.

Have you bled the coolant system properly? Theres another thread going on right now discussing bleeding procedures. You might give that a try.

My opnion is that its not the water, people used to use straight water on iron engines with no troubles back in the day. I dont see why it would cause you problems on your aluminum engine.

Using online sources you can replace your entire cooling system for Id say less than 300 dollars. Thats a lot of money for me personally, but if the rest of my car was in good working order Id go for it. Its hard to buy a car in the same league as my Intrigue for 300 dollars.

If the system is pressurizing properly running water shouldnt matter. Pressurizing the system increases the boiling point of water, I dont know the math on it. But I know it does.


Yes, this is true.


Your Intrigue should be running below 212 anyway unless youre sitting still perhaps. Even then with the AC on your fans should already be running.


The COOLANT temp still gets above 212*F even with a 50/50 mix of coolant/water and a properly functioning cooling system under normal operating conditions.

However, temperature of the ENGINE itself where the coolant passages run will exceed the boiling point of the water. Even at 15 PSI water boils at about 250*F. The water will vaporize upon contact, thus causing your current overheating problems to snowball since the steam does not have heat transfer properties of water in liquid form. Since your cap vents at 15 PSI, in theory the majority of the water could boil out of your cooling system if the engine was ran long enough because when water boils to steam it expands. Your water pump will only help the steam find it's exit through the cap

I say, get some regular green antifreeze and fill your car with it... just to see if the car overheats after a few weeks...this way you can easily determine if the straight water in the system is causing the issue.if it does not overheat, then flush the green stuff and get some prestone universal (yellow) coolant in there to avoid future damage... If it still overheats, move to water pump and inspect/replace it.

a few more tips

Make sure you do not have an air lock in your cooling system, that can easily cause an overheating issue. Im not sure about the 3.5l but the 3.8l has a few air purge valves you are supposed to open after a radiator flush.

make sure your fans are operational, i had one dead fan in my 98' and if i sat for more than a few minutes on a hot day the temp would rise above the 3/4 mark towards the red until i got moving again on the road...

thats the next thing i was gopnna ask, where are the air purge valves on the 3.5?

i hate this car now, i drained all the water out of the can and ran a 50/50 dexcool and water mix and the car still overheated. took the water pump off and there was nothing wrong with it, 3 mechanics told me to put it back on. im starting to think it needs a new motor or the radiator.

thats the next thing i was gopnna ask, where are the air purge valves on the 3.5?

i hate this car now, i drained all the water out of the can and ran a 50/50 dexcool and water mix and the car still overheated. took the water pump off and there was nothing wrong with it, 3 mechanics told me to put it back on. im starting to think it needs a new motor or the radiator.

Did you ever try replacing the thermostat? There was a TSB on the older 3.5L Intrigues that had the similar symptoms as you.

In the TSB it says the customer observes overheating when the temp is below 0*C (32*F) with the heater and fan on the highest setting when idling or driving slowly in traffic.

It says to replace the thermostat with a revised one that helps coolnt flow better. By now, all of the aftermarket thermpstats should have this revised design.

Check the radiator fan motors to make sure they are working. Just use some extra wire to temporarily hook them directly to the battery to see if they work.

Did you ever check and/or replace your coolant lid?

i removed the thermostat, the fans are working fine, and i replaced the water pump yesterday.

i did notice after i changed the water pump and sdtarted the car it was smoking, so i think its the heads or head gasket now SMH! i dont get it tho i dont have any leaks and theres no water in the oil?!?

I would change the thermostat next..... Then the radiator if the thermostat does not do the trick.

so you think its the thermostat or radiator inbstead of the heads or head gaskets?

The first thing I would have done is replace the thermostat and flush the system to make sure there was no blockage. Esp. at your mileage and age and this is the most common cause for overheating in the Intrigue. the thermostat should be a piece of cake for you after all of this.

The head gasket COULD be the problem but you never mentioned about adding coolant or excessive white smoke. To me, the head gasket is the last (and most expensive) option.

I believe in doing the cheapest and easiest repairs first. Not much money invested and there is no harm replacing the thermostat esp. at your mileage. BTW, I would recommend switching to the Prestone Universal Extended Life.

I just crossed 178k miles on my Intrigue. Replaced the thermostat in the late fall. I'm at the point of replacing this car very soon. Great car for me but it's getting too frustrating and I (read: my wife) refuse to put any more money into the car outside of regular maintenance. With my daily commute of 65 miles RT, the comfort level in the car is deteriorating rapidly. i still get 24-25 mpg though.

ive flushed the system plenty of times. can these cars be ran without thermostats in them?

i havent had coolant in the car for a while now except for a few days ago and it still overheated but didnt smoke. the only time it smokes is on start up and its a fine mist and the time i replaced the water pump it was smoking but stopped so im lost.

im just trying to get the car fixed to last until i can get another car.

I would change the thermostat next. Like I mentioned, no harm in changing it since at your vehicle age and mileage, it could go at any time. And it does not cost much. I paid $35 for mine and installed it myself.

i understand your saying change it but there isnt a thermostat in the car now, i took it out! are you saying intrigues cant be ran without thermostats in them?!?

I think most of us are just curious how you removed the actual thermostat on the 3.5, its built into the water outlet, and if it could be easily removed I would think they would sell replacements in that manner, instead of selling an entire new water outlet.

So, I guess if you found a way to get that bugger out of there, then in theory it should be fine. But its not really designed to be removed.

I'm not sure if the Intrigue can function normally without the thermostat attached. I'm not a mechanic just someone who likes cars and tries to learn as much as i can about my own cars. My guess after seeing the design of this thermostat is that there is no way for the coolant to flow with the thermostat off since all flow goes through the attached tubes. I could be wrong. It wouldn't be the first time and definitely won't be the last.

when you remove the housing if you twist the thermostat it comes right out of the housing. when i went to autozone they showed me just a thermostat not a whole water inlet housing with the thermostat attatched

when you remove the housing if you twist the thermostat it comes right out of the housing. when i went to autozone they showed me just a thermostat not a whole water inlet housing with the thermostat attatched

Sounds about right. When I replaced it on the wife's old car it was the same way. The Saturn 1.9L (all years) implements a similar design. There are two pegs that go against a couple tabs on the housing. They give you a stiff cardboard or sometimes plastic tube to push on them with to replace it.

yep. heres a picture

http://i80.photobucket.com/albums/j190/930-870/Jun10_002.jpg

This is the thermostat unit I purchased:

http://www.rockauto.com/catalog/raframecatalog.php

The water outlets were attached to the thermostat. I didn't see anyway to remove the thermostat itself from these metal hoses. This is why i said I didn't see how it could flow without the thermostat in place.

If you can remove and apparently you did, I would just replace it. That's a $10 part and you have to put it back in anyway.

to answer your question again, it should flow with the thermostat off in your situation.

We are going to get this problems solved yet.:iceslolan

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i didnt know i had to whip out the digital camera....i just took em wit my pos phone camera. and heres a picture of the thermostat out of the housing
http://i80.photobucket.com/albums/j190/930-870/Jun10_003.jpg

did you bleed the cooling system?
there is a screw on top of the thermo housing that will have a flat head screwdriver slot in it. start the car and let it run for a while than turn the screw until coolant comes out if there is alot of steam it will be ok when the coolant comes out than turn the screw back until it stops and it should help with the overheating, you my have an air pocket in the system which may cause it to overheat.
you may have to do this two or three times before it stops. give it a try and let us know what happens.

theres not a screw on the thermostat housing. ive beld it plenty of times and still no luck. its been overheating for a while now so i know it cant be just air in the system. shits really beginning to bother me.

If the thermostat or bleediing the system is not the problem, then the next step is looking at the water pump or radiator.

I'va always used Red Line Wetter Water in my cars ('01 Intrigue 3.5, '87 442, ?? Grand Crapavan & '05 Hoda Pilot) Each car displayed lower operating temp and it supposably also helps "move" air pockets out by capturing them and helping them move. (http://www.redlineoil.com/products_coolant.asp):iceslolan

Also, I have heard/read that using distilled water w/ DexCool helps prevent foaming and any other problems reported w/ using DexCool. Lack of minerals in distilled water also might keep the pH levels from changing over time.

I had my Intrigue flushed & filled w/ DexCool/Distilled H2O at about 110k miles and added Wetter Water again. Haven't had any measuarable coolant loss, about a pint every 5k miles. GM does sell a treatment pill that seals small leaks in head gaskets but you can't add it to the overflow tank but disconnect the upper hose and add it then.

There has been no mention of how high the temp is going or if this happens w/ the A/C on or off. Also is the cooling system taking less than what is required for a full fill? (lending credence to the clogged radiator possibility)

Change the radiator cap. It's on top of the reservoir unit. You HAVE to use a 50/50 anti-freeze mix in the Intrigue because it increases the amount of heat that the system can handle.

I went thru this SAME problem for months, I finally went to a shop and they were able to pressure check the filler/overflow bottle cover. It never seemed to be coming from there but after they said it was bad I spent $11 to get a replacement and NEVER had another problem. Hope this helps!! Good Luck.

After spending to much time and money on test equipment and new parts I fixed the problem. 1st symptoms - Over heats below 2000 rpms. Bleeding doesn't help. Runs ok on the highway if you have gotten most of the air out. The problem with the 3.5 it's a reverse flow engine with a dual thermostat that opens at the block (silver disk ) above 2000 rpm (of pressure) and a regular type seal at the radiator ( above 180 degrees ). You can't get all the air out and this causes the popping sound, at the front of the heater core. If you rev above 2000 rpm's it moves the air around and temporarily stops the popping. Now for the fix :smile: ..... Drum roll please ....... :smile: Remove the thermostat, if this is the 1st time you should get a new seal, take a 5/32 drill 2 holes in the block side of the silver disk ( 180 degrees apart ) and turn it so one is up and the other is down. This will allow air to move through the top hole and water to move through the lower. Don't forget a little sealer on the bolts for the thermostat and to bleed excess air out of the radiator by using the little plastic drain at the top passenger side of the radiator. This plug doesn't have to come all the way out. it drains from the side. You can slip a small drain hose over the side drain to capture radiator fluid that squirts out. I wasted about 80 hours until I remembered my 1966 mustang had holes in it for a similar reason.

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Because this problem is alive and many of us have been searching for a solution. We are reading all of the blogs old and knew. If I save one person the money I wasted it will have been worth my time posting to multiple blogs. Sorry if this bothers you/

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I agree that your fix isnt a very good one.

I had a problem with my car overheating when it was below freezing, which there is a TSB out about such an issue.

I replaced the thermostat and housing as per the TSB, and for good measure drilled not one but two holes in the thermostat, similar to what youre saying.

Does my car overheat? No. Does it now take considerably longer to get to operating temperature? Why yes, yes it does.

A drilled thermostat is usually never the answer to any sort of problem, I just didnt want to risk having the same issue again, and I paid for it in another area.

Air in the cooling system is probably the biggest cause of cooling issues, especially after replacing a defective coolant part...a lot of people, mechanics included simply dont understand that a closed system like the one on the 3.5 Intrigue WILL NOT bleed itself, you have to bleed it, manually, often several times....sounds to me like you finally just managed to bleed it right, and just so happened to drill up the thermostat at the same time.

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....sounds to me like you finally just managed to bleed it right, and just so happened to drill up the thermostat at the same time.
Agreed. Coincidence.

Quick question!...What's the difference between a thermostat that is not closing properly and one with holes drilled in it where none should be?
Answer.... No difference, you get a car that doesn't quite produce the heat it should.

I too have not had any problems bleeding out an intrigue. In fact it was a lot easier than an old 3100 on a corsica I use to deal with and many other GM's..

Odd that you guys would fire this post back up. I've been ready the many old posts on various sites about intrigue overheating. My daughters 2002 overheated and the heat stopped working. I replaced the thermostat with an OEM part and followed the service manual procedure for bleeding; still overheated; went through the bleed procedure of adding a flushing T and pulling the top radiator hose twice. Now the car maintains temp below half; but the heat stops working after a while. On the highway it takes roughly 3 miles. Get the RPM's over 2000 and the heat will come back. I'm leaning toward a restriction in the heater core that once it gets hot, plugs it from expansion and eventually with the high RPM's enough water flow eventually moves it. Sooner or latter it comes back, but I"m grapsing at straws. The water pump appears to be working by observing the flow in the tank.

ANY ideas or input are appreciated as this is driving me nuts.

You could try flushing the heater core out...back-flushing I believe they call it. Ive seen several videos on the internet where people use compressed air to remove gunk out of the heater core...basically they take a mixture of water and compressed air and push it through the heater core in the opposite direction it would normally run...but I can honestly say ive never tried it, never had the need to.

On most cars you can bypass the heater core by running your own hoses...but for you that would be more of a diagnostic step than a fix....unless your daughter just enjoys having no heat in her car:)

The best thing for anybody to do to maintain the cooling system is to take the car into the dealer every 5 or 6 years and having a cooling system flush done. Over time the cooling cavity inside the block develops aluminum scale which can cause the engine to over heat and chemicals they used during the flushing procedure gets rid of them. I just had mine done for the second time in 11 years. Also, replace (or test) the pressure cap on the reservoir every few years or whenever you have a cooling problem.

The best thing for anybody to do to maintain the cooling system is to take the car into the dealer every 5 or 6 years and having a cooling system flush done. Over time the cooling cavity inside the block develops aluminum scale which can cause the engine to over heat and chemicals they used during the flushing procedure gets rid of them. I just had mine done for the second time in 11 years. Also, replace (or test) the pressure cap on the reservoir every few years or whenever you have a cooling problem.

As for the thermostat going bad, my experience has been that when it goes bad it will not open so there is no way you can drive the car more than a few miles.

You may just well have a head gasket problem. Just because its not in your oil. You may be burning it. Did you pressure check the cooling system? Change the thermostat? Do the easy things first. Have you monitored if your having to top up your coolant? Coooling system is straight forward. If your rad hose never gets soft or spungy when the thermostat opens....you have head gasket problems, and your friend is right....which explains the puff of white smoke when you first start your car. Spend $50.00 to have it checked if your not sure. I believe whats happening is your engine is forcing air into your cooling system through a blown head gasket. I have seen this before....and what your describing is either an air lock in the system or blown head gasket.

By an old goodwrench engine technician: it's probably not a head gasket problem. As his experience, he never ever need to change head gasket on 3.5l olds engine. 3 possibles causes

1: hose leaking (in particular top hose of the heater circuit)

2: Throtle body coolant chambers gasket leak

3: The most common and hard to find: Cross over body gasket leakage
This part is locate at the left side in between the two heads just over the cross over exhaust pipe. The heat of the exhaust quickly dry the leak and you just smell coolant without see anything.

cost and time of repair: aprox 55$ for gaskets and 4 hours for skilled mecanician. (need to cut bolt of the coolant cross over body to avoid exhaust cross over conduct removing)

Symptoms on my Intrigue 2000 before repair:

- Bubbling sound in the heater at cold few months before

- Coolant consumption... more and more

- Finally, a lot of air at radiator purge, coolant pump discharge and overheating.


I try many things before... including the "miraculous" 5/32 hole in the inner parts of the thermostat without succes.

Finally we change cross over body gaskets and throtle body gasket.

My olds run now like a new one.

I wish someone would have told me this a few years ago, I got rid of the pos.

What the guy posted above me was the issues I had. System was full with air and would dump coolant from the bottle, the last straw for me was when it blew coolant all over my arm from my wrist to my elbow and gave me 2nd and 3rd degree burns.