Still Overheating, Please help

Sounds like the cooling system is still clogged.

My suggestion is to take the thermostat out and see how the car does. That will simplify the trouble shooting.

Also, take off the radiator cap and let the car warm up, and watch the coolant flow through the radiator. You should see coolant flowing while the engine is running. If you don't see a good flow, then the cooling system is still clogged.

Have someone use a real temperature gauge on the system: either the type that screws in or an external infrared type. Have someone use a combustion gas sniffer on the open coolant reservoir.

BTW: One of the worst things you can do is to open the cooling system cap when the engine is hot. You're going to get a warped or cracked head doing that. A 15 lb. pressure cap raises the boiling point of water to 250F.

I haven't checked it since they put the new radiator in, but the tech called me and said their was little circulation before. Now with the new radiator he said the circulation is much better. The last thing that was done was the new radiator. They suspect that it might have some air pockets in the radiator. Is this common since it is a brand new radiator ? I will have to wait and see what they say tomorrow. I went over this evening after they closed and I took it out for about 20-30 minutes, and it was still overheating. What all should I have them check ?

Regards, KDawg

Could this be a faulty intake manifold ? Just a thought.

This is just a thought...... a few years ago I had a Ford LTD....which continuously overheated. Tried a bunch of things to no avail. Finally replaced the FAN, fan was a variable flex type, which, (sheesh, it was so long ago, I forget exactly how it worked,) but I remember the fan using a fluid coupling instead of a mechanical coupling,

Fan was turning but the fan blades were slipping and not giving enough cooling power. Car ran fine at high speeds, with airflow providing the cooling power, but when brought down to side street speed, the car would overheat.

Just a thought.

I got the car used about 4 months ago, and the thing ran great. The temp rarely ever went above 1/4 on the gauge. Evn on hot days it was fine, and the odd time it would go up to 1/2 if I was idling for a bit. Then all of a sudden the temp went up into the red. I took it in, and they said the fan motor was gone, which made perfect sense to me since it was fine on the highway but overheated while going slow. It has been quite cool where i am for the past 2 weeks, and I have taken the car out late at night when it has been very cool and it has still overheated. I have also verified with another user on Newsgroups who has the exact same car and he said that his never goes above 1/2. Thanks for the response. I am seriously starting to lean towards a thermostat problem. Even though they replaced it about a week ago, I think it is getting stuck, or the sensor is not working. When I checked the air between the fan and the engine it felt cool, so I am guessing that there is no circulation. It's a new rad so I know that rad is probably fine. The fan comes on about 1/2 way up the gauge. I have verified this by idling the car in my driveway and noting when the fan comes on.

"KDawg" wrote

Ok....does the temperature continue to just climb right into the red zone if you let it idle long enough? That seems to be what you are saying, but I'm not sure. If the temp continues to climb even with the fan on...then yes, you do have some sort of problem. And if, as you say, the air that the fan is pushing feels cool, then I would agree with your assessment that there is a circulation problem.

Just want to be sure you aren't chasing your tail for nothing.

Ian

I'm gonna have to go with Shi on this one but with a small twist Have you checked to see if the coolant temp sender was damaged during one of your earlier overheats May be as simple as comparing the ECM input of Coolant temp to the guage on the dash I have seen a number of these senders read way off after they have been overheated

Just my 2 cents worth............................. Good Luck

I know this sounds like a bad advertising pitch but this shiz works, points of example being my Fiero's cooling system, and all the Holden Commodores that have been in my family...

RMI-25 is by far the most ninja cooling system additive you can use, it cleans up the crap and keeps the coolant clean - the Fiero's 3800 is beautiful clean inside thanks to this stuff, far cleaner than most other

Nick.

As far as what's normal and what's not with this particular car and engine. I own the exact car/engine setup of the same year. '95 right? I've NEVER once in the 4 years that I've owned this car seen the temp gauge go past half way no matter how hot it is outside, or how long I've been idling. The fan always comes on at half, or just a hair past, and immediately cools the engine down. Iowa where winters can be -25 with windchill, and summers can pass 100. Now, I think only a professional, and unfortunately, more time and money are all that's going to solve this. A professional who is present to inspect the car is what I mean. A previous poster suggested running the car without a thermostat at all to see what happens, I like that idea myself. I had mine replaced, and the replacement was bad, mine was stuck open. Another thing that I personally see as a very good possibility, I think Geoff mentioned this, is that the system could still have a blockage or even just a partial blockage. I'm betting on a partial blockage. That sludge can be NASTY and almost impossible to remove. Perhaps when the car is cool, open the cap and inspect the fluid for ANYTHING big or tiny, that is solid floating in the coolant, indicating more gunk. And yet another, as mentioned, is that something that monitors the coolant temp and is therefore used by the ECM as part of it's decision making, is fouled from a previous overheat.

Tony

You obviously spent a lot of money on several items. Are you sure it has enough coolant? With the engine cool check the level in the radiator. You can feel the hoses with the engine idling to get an idea of the circulation. (When the thermostat opens you will feel the hot coolant flow.) Drive around a bit and see if it gets hot. If so I would think some part you think good may be bad.

Gary

Take you belt off and see if the AC and power accessories turn freely.

Gary

Yup its an electric fan, and it comes on when it is supposed to. Somewhere around 1/2 way on the temp gauge it turns on, and it stays on after the car is turned off if it needs to cool down further.

Yup its an electric fan, and it comes on when it is supposed to. Somewhere around 1/2 way on the temp gauge it turns on, and it stays on after the car is turned off if it needs to cool down further.

Thanks for the replay, but I no longer have that car. I am not troubleshooting a check engine light on a 94 Grand AM.

Oops I meant I am NOW troubleshooting a check engine light

Seems to me...

1. You didn't have a problem until the radiator fan motor quit
2. You still only have a problem at speeds at which your cooling system depends on the radiator fan for airflow.

My guess is you still have problems with air flow from the fan.

I can't f> 1995 Pontiac Grand Am Quad 4 approx 160K