PontiacBonnevilleClub.com

Friend of mine has a 98 Intrique that I helped him buy. The car has 200k on it, but has a new engine with 60k installed. Also a new radiator was installed before he bought the car. He has owned it for a few months, and never really overheated until it got really warm out. It will get as hot as 250° before he has to shut it down and let it cool. I haven't diagnosed it in person yet, but this is what I know.

New radiator
New thermostat (180°)
New water pump
New intake gaskets
New UIM
Fans are working properly
No oil in coolant
No coolant in oil
No white smoke
Coolant is boiling, but not over, no steam
No air in system, has been burped properly
You can feel the coolant running through the hoses when you squeeze them

My dad suggested checking to make sure the condensor is getting proper flow and isn't blocked with dirt, bugs or bent fins. I'm gonna check that out when I see the car on Thursday. Any other suggestions, even far-fetched are appreciated. We are all really stumped on this one.

This may be a stupid question. But has the coolant been tested to see if the coolant/water ratio is correct?

Definately something else to check, thanks.

Check or replace the radiator cap. Also verify the pump is working. I remember in the past there was a case or two where the impeller of the pump broke.

agreed with the cap. I think the Intrigue uses a Pressured system, that is different than the Bonneville.

Also, are you sure that the temp gauge is correct?? Its a long shot but something to think about

Maybe something in the system is clogged. Like to a point that is has flow, but really restricted flow. Do you happen to know if anyone dumped stop leak in the radiator?

Coolant has been tested, exactly 50/50.
New radiator cap.
Condensor has been cleaned out, lots of junk in it.

However, still overheating. Like Terry was saying, it has to be plugged somewhere. When he comes on Thursday I'll do an extensive examination.

harofreak00 wrote: it has to be plugged somewhere. When he comes on Thursday I'll do an extensive examination.

Is it possible or worth taking the engine apart to see how the coolant ports/channels look? If they are as gunked up as mine were, I could see why it would overheat.

I know that it is unusual, but check compression, or do a cylinder leak down test to check the condition of the head gaskets. The bubbling could be exhaust gas getting into the coolant.

I would wonder if something in the block is clogged up, I remember somebody on here finding bits of an old water pump impeller in their coolant channels.

Had a look at it tonight.

Tested that the coolant temp sensor is working correct, yes it is.
Flushed out the block and radiator, both are flowing just fine.
Water pump is working.
Did a compression test: 135-150 across the board.

Only thing we can come up with now is that the radiator is not working correctly. Not getting proper airflow? Wrong size core? The bumper cover doesn't really allow much airflow as it is. I think I might take the cover off and see if it cools better. I gave him one of my cars and I'm holding onto it until I can get it figured out. Any more ideas are welcome.

I am curious. Does it heat up worse when driving? If you let it idle when it starts getting hot, does it cool back down with the fans, or does it keep escalating? How does the A/C work?

AC works fine.

It gets hot whether is idling or driving at full speed. The fans do nothing.

Does the temp go down after turning heat on high when driving it? I battled a similar situation with a 1990 Pontiac Sunbird and led to head gasket failure 40k later. Are head gaskets good?

I'm sure you have bled system and relieved any air pockets?

Why was all of the recent work done? Was it to try and fix this problem?

And did the issue suddenly appear, or it got worse and worse as it got warmer?

And you did clean out between the condenser and radiator correct? Or at least look in there?

Fans don't work, or they don't sufficiently cool it off?

00Beast wrote:Fans don't work, or they don't sufficiently cool it off?

I'm assuming that they just don't sufficiently cool it.

I never noticed before that these cars don't seem to have a grille.

00Beast wrote:Fans don't work, or they don't sufficiently cool it off?

He said it does it when driving full speed, so I think he meant fans do not bring the temp down.

Make sure the shroud for Tue radiator is intact. There's a duct that guides the air up from under the car. Without that it won't get any air at all.