I just recently had my ST installed and the car is overheating. I checked all of my hoses and everything is hooked up. I found out yesterday that the shop installed stock plugs in place of one step colder plugs. I was told that this could be my problem I just wanted to ask you guys if you think that is the problem or to look somewhere else for the overheating problem.

The car goes to the tuner on tuesday and the new plugs come in on monday I just want to solve my overheating issue before it goes to the tuner. Also is there a DIY for spark plugs. My car is a 04 G35 coupe. Thanks guys

 

Just to add there is no SES light when it overheats or runs. Thanks

 

Have you checked there are no air pockets in the cooling system? I recently swapped out old coolant for new and ran hot immediately. I limped back to the shop where they re-attached what I assume was an air extractor hose and topped off coolant levels again. Problem solved.

 

No, I haven't checked for air pockets. I will have the shop check tomorrow. The thing is the car didn't overheat right away I would say after 10min of slow driving 40-50mph (not tuned yet).

 

Maybe there are air pockets in the cooling system because the was fluctuating between normal and hot a couple of times. Thanks for the info I will have the shop check it out.

 

Is there anything else I should check out for my overheating problem besides changing the plugs and checking for air in the system?

 

+1 on the air pockets in the cooling system. I bet that's where your problems lies. Especially under the conditions under which you said it overheated. Of course make sure you have no coolant leaks and corect coolant level. It could always be a bad thermostat or water pump, but probably not under the circumstances you describe.

 

+1 on the air pockets in the cooling system. I bet that's where your problems lie. Especially under the conditions under which you said it overheated. Of course make sure you have no coolant leaks and corect coolant level. It could always be a bad thermostat or water pump, but probably not under the circumstances you describe. Good luck.

 

Sounds look air in cooling system.
Does your heater work? If the air is cold or luke warm, its a definate sign of air in the cooling system.

The spark plug type will not make your engine run any hotter or colder. Although I would definately recommend a set of NGK one step colder Iridium plugs for FI. http://www.forgedinternals.com/store/home.php?cat=275

 

How do you check for air pockets? Is it something I can do or does a shop have to do it? Thanks.

 

A spill funnel, and some time is all you need. If you dont have heat, then you have air pockets. Your heat should be extremely hot when all the air is expelled from the system. You will bubble out the coolant from the rad, and also from the purge cap near the passenger side firewall.