Thread: Cooling issue

Hey, sorry if this was already posted somewhere.

I have a 2003 Grand Prix GT 3.8L, 136,793KMs. It's my wife's daily driver.

Anyways, this winter I noticed that the heat wasn't blowing that well and that the engine temp was getting a little higher than usual; upon checking the coolant I noticed that the reservoir tank was bone dry! I topped it up and also took the cap off for the radiator hell of it and noticed some brown sludge (I read somewhere that antifreeze can decompose and turn that way when air gets to it, which happens if the coolant level is really low. I'm sort of hanging onto that and trying to not to think of a head gasket!). I'm hoping against hope that it's not a head gasket issue, I don't smell that telltale sweet coolant smell, the exhaust isn't really white and cloudy, and I recently had the oil changed and they didn't see anything that would indicate coolant mixing with oil.

Anyways, after I added more coolant the engine temp was normal for a day then went back to getting higher than normal again, I checked and the coolant reservoir wasn't dry but it was very low (without any signs of leakage in the driveway) so I topped it up again. I then thought of adding Stop Leak just in case but when I went to add it to the rad I only got about a table spoon in and it was full. SO, did I maybe add to much coolant? Since I've topped up the coolant the last time the levels have remained the same. I had the thermostat changed thinking that maybe it was stuck closed and not letting the coolant circulate; it's not normal for the rad to be full to the top when the car has been cool and not running for an entire day I thought? That did seem to fix the luke-warm interior heat issue within the vehicle.

Just as a point of reference, the engine temp always sat between the lowest point and the first major mark (I think that's 70 and 85 degrees, I can't remember now and I can't seem to find a picture haha); I've had the car for about 5 yrs. When it gets "hotter than normal" it will climb slightly above the first major mark when idling but when I start driving it will go down a bit. I was sitting in the driveway today and noticed that when it gets around 85-90 degrees I don't hear the fans coming on, maybe a blown fuse?

Sorry for the long post but I am trying to flush out resolutions other than "replace the head gasket" or "replace the manifold gasket" haha.

If anybody has any input I would really appreciate it.

Yes, the radiator should be full to the top when cold. It's doubtful it's a headgasket, they fail in 3800s. Sounds like was low.....then when you filled it, the block was probably down a bit as well. So when you checked it again it needed to be topped off. If it's not using coolant now, I'd just keep an eye on it for a couple weeks.

This picture shows about where normal operating temperature is:
2011-03-12_17-31-21_916.jpg

A normal 195 degree thermostat will open right about when the needle gets just past the large white line where the needle is about right now. In the meantime, fill your radiator up each day if it's low and keep an eye on it. Like koRnhead said, it's probably just low and needed to be bled out a bit.

The HG's rarely go on these motors, but the LIM gaskets need to be replaced if not running the updated aluminum ones. If you look where the head and lower intake meet the block and see a black edge, then it's time for LIM gaskets. Do a coolant flush and get rid of the Dexcool as this is the source of the brown sludge. Once all of the old Dex is out just fill it up with conventional green coolant and some distilled water and call it a day.

Since you had the thermostat changed, did you bleed the cooling system properly? If not you may have air trapped in the system (which is common on these motors).

strange that the instructions on the stop leak stuff would say to pour it directly into the rad then! Thanks for the advice

Yes I was told I might need to bleed it, I wi try that...any tips for the process?

I'm going to try bleeding it, Im hoping to avoid a big cost for the moment, wife just went back to work after mat leave so $ isn't really in abundance haha. I guess you gotta do what you gotta do though!

Originally Posted by ZSharp1985

Yes I was told I might need to bleed it, I wi try that...any tips for the process?

Per Scotty- open the rad cap, let the car idle till the fans come on, then open the bleeder screw till a solid stream of coolant comes out. then shut the screw, top off the rad,and cap it.

I wouldn't go for stop leak. You don't want to put anything in your radiator that could potentially gel up. Personally I've never used it, but I saw some videos on YouTube showing its results. Didn't look so good. If it's just a temporary fix, like your going to sell the car in a month or flush out cooling system in the near future, go for it. Otherwise if you are gonna try and use this as a permanent fix, I'd try and find something a little bit better.

Originally Posted by FordMan77

Per Scotty- open the rad cap, let the car idle till the fans come on, then open the bleeder screw till a solid stream of coolant comes out. then shut the screw, top off the rad,and cap it.

What do if coolant steadily leaks out of the rad while car is running? Even if I take the rad cap off when it's totally cold then start the car fluid starts coming out of the opening.

Cap it off. Won't make a difference if the car is stone cold or not. Take the radiator cap off. Fill to the top. Start your car. Pour more coolant in if necessary. Open the bleeder screw on top the thermostat housing until coolant comes out of it, like mentioned above. After that, go back to your radiator and fill it up more if need be. If coolant starts coming out from the radiator, cap it off and you should be done.

Originally Posted by 01Grand PrixGT

Cap it off. Won't make a difference if the car is stone cold or not. Take the radiator cap off. Fill to the top. Start your car. Pour more coolant in if necessary. Open the bleeder screw on top the thermostat housing until coolant comes out of it, like mentioned above. After that, go back to your radiator and fill it up more if need be. If coolant starts coming out from the radiator, cap it off and you should be done.

Alright cool, I understand that, was just pointing out that during this process fluid is also coming out of the open rad cap...I guess just don't worry about that until fluid is coming out of the thermostat bleeder then.

Thanks again