Radiator problems?

Asked by Sep 09, 2016 at 03:31 PM about the 2008 Pontiac Grand Prix Base

Question type: Maintenance & Repair

I have a 4 dr 2008 Pontiac grand prix. I feel I might have a minor or slow leak. I put antifreeze in my car about 2/3 mos ago maybe more or less don't quite remember but as of last wk I noticed my car beginning to ride a little rough and sound rougher too. then yesterday the line actually moved up. On the way home it went up all the way saying turn car off to cool, overheat. So I got home, let it sit, poured antifreeze in it this morning, drop kids off etc everything was fine. On my lunch break I was driving back home and the line went into red and the message came up saying turn car off to cool. when I got home I checked the antifreeze/coolant level and it was still full so I'm puzzled as to what the hell could be wrong for it to still be over heating if I have antifreeze and coolant in there? Please help!!

7 Answers


Sounds like a bad head gasket

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Find out where the leak is first. Then make sure the coolant is at the proper level. Air in the system will sometimes cause it to over heat as well as a stuck closed thermostat, faulty water pump, to head gasket as mentioned above. Your mechanic can perform some tests of the coolant system and engine to determine what specifically is your issue. No sense in replacing parts you don't have to.

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Because it is running rough makes me believe head gasket. Running hot is one thing but rough running could be head or intake gasket.

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I agree it sounds like gaskets, but could also be air trapped in the system as well. Your car likely has the original coolant in it which does need to be changed occasionally. This would be the right time to have the system drained and flushed and professionally refilled to make sure there is no air trapped in the system. They can also pressure test to determine if the gaskets are good. If they're not, you can either replace them, which is a fairly expensive project, or add a couple of units of Bars Leak to the system which will reseal them if they are not too far gone. That "fix" only costs about $20 and takes 10 minutes. I used it on my Grand Prix 4 years ago and its still doing fine. While they're working on your car have it scanned for trouble codes in case the rough running is being caused by something else.

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Best Answer Mark helpful

You guys are great and I thk yu for your response. So I figured out some of the problem. My car is no longer over heating thk GOD!! So I was pouring the anti freeze/coolant in the reservoir (dex cool) tank. Well sat after my boys football game I was dropping someone off and it started over heating again when we made it to our destination. So they popped the hood and twisted the radiator cap off. Nothing but air had come out. I was not pouring my anti freeze in the right spot. I thought you were suppose to pour it in the dex cool/reservoir tank. So as soon as we took the radiator cap off every thing in the reservoir started flowing over to the radiator area. I guess b/c I was like bone dry or empty it was building up w/ just air and causing it to not be able to flow through properly to the engine. So needless to say ive learned a lesson. My car has been riding fine since and I will be returning the thermostat parts I bought. My only small issue is my kids father believes I shouldn't have to pour anti freeze in my car I got it 2 yrs ago and have NEVER had any issues and no accidents. So about 3-5 mos ago why would I have had to put anti freeze in it? He says you should be able to ride for yrs w/ out needing to put any anti freeze/coolant in there. So it makes me wonder if I have a small leak somewhere. Although when I get on the ground I do not see anything leaking out. I will def have a mechanic looking into this but I'm glad I was able to resolve some part of my problem. Thks Again!!


I agree. The system should never need more that a very small amount of coolant added to it. You likely have a small internal leak. Probably a head gasket. That's where the Bars Leak comes in. Go to the auto parts store and buy 2 units of Bars Leak. Read the instructions and put it in the way they say. Make sure the radiator and the overflow reservoir are filled to the right level and keep an eye on things over the next few months. Probably that will seal it up so you don't have to have the engine taken apart to replace gaskets. The Bars Leak, by the way is a proven product approved by GM for use in their cars. It will not harm anything.

1 people found this helpful.

wow yu really are awesome!! I rarely use these sort of sites b/c sometimes yu never get a response or very little help but yu as well as the others has really helped. I'm a woman and I couldn't fix my own car but btwn my kids father & my brother they've made me sit outside w/ them when they were doing small things such as oil changes, brakes, tire replacements etc over the yrs on any cars ive had. And I will say that has helped me to know little/small things to do. I feel other women should know just a little bit b/c men are not always present if/when things may happen and yes yu should take it to a professional but sometimes its good to still know things as well on your own. Like this where I don't have to go pay hundreds of dollars to have someone else do a job that could be done by a male figure I may know. So I thk yu and I will be going to get these parts. Its like your answers were right on target to my issue. I'm very appreciative!!

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