Thread: 2008 grand prix runs hot

Most likely you could take it apart and clean the gunk out of the fins to make air flow through the radiator fins. Radiators are less than $100 so you might want to consider just putting a new one in. I replaced everything in the cooling system just like you have and I still had the problem on hot days when idling for long periods with out moving. Thats why it makes sense when you are moving you are pushing enough air through the radiator to keep it cool, but when sitting still the fans dont pull enough air flow to overcome the blocked area of the radiator. Mine had at least 30% of the surface area completely filled over not allowing any air through. This could be a time only fix if you are handy on working on your car.

Id much rather spend a couple hundred on a new radiator rather than almost 2 grand on a block resurface though. My issues is knowing for sure what it is I truly need since I really cant do the work myself.
Here is a quick rundown of what I have been though. Last summer my water pump went so I had a shop replace it as well as the belt. Then over the winter my heat wasnt working so twice I had the same shop flush my heater core. When I was there the guy at the shop told me that I might start experiencing issues with corrosion or overheating but I didnt think much of it until sometime mid April of this year when I noticed my temp gauge shooting up towards the red while sitting in traffic. I bought a new thermostat and put that in but no change. Then I bring it into the auto shop teacher where I work and he first purged the air from the system. When that didnt work he agreed to flush my radiator (not sure the method but all I know is he had me by a 10 dollar kit at my local auto store to do it). That seemed to help for about 2 weeks. Which brings me to this week where I brought it to another local shop where he diagnosed it with bad head gaskets. Another thing to mention....when I drove it home from the shop which is only about a mile from my house I noticed that the temp gauge is not moving at all now. It was only a five minute drive but it usually will make the gauge move at least a little. All in all, I just want this car which Ive only had 2 years to be functional again. With summer coming up, I dont want to constantly worry about temp issues. Thanks for listening.

So today is the first day I have drivien my car since they diagnosed it with needing head gaskets. At first the gauge didnt move at all for the first few miles, then it shot up to the line by the red and stayed there all 25 miles to work with the air on with no traffic. Now I dont know what they did to it because at least before the gauge would lower once the air came on. Now I have to drive home late today in traffic in 80 degree plus heat and I dont know if thats a true reading or not and if its even safe to drive. What do you guys think?

Have you been losing any coolant? Does your oil look like chocolate milk?

Id probably avoid using the AC for now

I checked on my lunch and I was down a little bit of coolant but not much and it wasnt milky. I felt the bottom radiator hose while it was running and although it was hot it wasnt scalding like the top hose. Plus it didnt feel firm, I have a feeling that this may be my issue. It may be wishful thinking.Once I added some coolant I sat in my parking spot for 45 minutes with the air running just to see how high the gauge would go. It actually stayed half way between the middle and top line but I just hope it doesnt go higher highway while driving home. Reread your post and you said to avoid the air. I alwaysd thought that that was the only way to get the fans on manually if it gets hot?

Running the AC creates extra heat that is why the fans come on. The hoses should feel like that one has hot coolant coming out of the engine the other as cooled coolant coming out of the radiator. Does not seem like a head gasket. Im still thinking you have an airflow problem with the radiator being gunked up

They do get hot, why do you think they are in the very front of the car with dual fans on them? The whole point of moving air through them is to cool the refrigerant back to liquid form. They are often referred to has HEAT transfers. When you turn on the AC you are literally making a hot spot right in front of the radiator. You might get two fans but one is most likely by a blocked area of the radiator and the other is now drawing in pre-heated air. You are right with out blockage the extra air might help, but if you have airflow blockage its gonna hurt you. Go outside and touch your home AC condenser when its running you will feel some warmth on it hopefully not much because the fan on it is doing its job.

I appreciate all the advice.One last question...How do I know for sure if I need the heads rebuilt as opposed to a faulty radiator or maybe even a bad coolant sensor?

I just got the car back last week after having the valves and heads redone. I also had the radiator replaced so that they were no further problems. Things were great for a few days then on my way home last wednesday my car started bucking to the point where it stalled and I had to get it towed to the place where I got the work done. Initially he said that either one of my sensors was bad or my something was bad with my cap and wires which he said ran from 2 to 4 hundred dollars. Luckily it was just corrosion in my distributor cap or something like that and there was no charge. I have never had a car with this many issues to the point where I dont want to drive it anymore. It has 180 thousand miles and I expect problems to happen but it seems like every week its something else.

And the hits keep coming......On my way home yesterday my check engine light came on. I brought it to an advanced auto in my town and it brought up 3 codes...P0171,P0336 and P0420. The guy explained to me what they were and that the most important one was the crankshaft position sensor which was the cheapest part but something I cant do without a shop. The oxygen sensors he said I could install myself but he said he wasnt sure if it was the upstream or downstream sensor. I dont get how this could be happening if the guy said it was corrosion? I called the shop again and left a message.My car drove fine today.Is it possible that when they did my heads they messed with some wires and caused these errors or do you think these are unrelated?

Youre right about that but since my memory is shot Im probably the one at fault calling it by the wrong name.

Spoke to the shop again and he is going to rescan the codes to see whats going on.Im really hoping something else is triggering these codes because I dont want to have my car die again in traffic if it is the CPS.

I just had my crankshaft sensor replaced but my engine light still goes off for my O2 sensor? Is there a way I can find out which one, upstream or downstream, with a code tester?