Thread: Thermostat on 04+ question

Having just passed 60k miles, I've been doing some maintenance (coolant, tranny, brakepads, plugs, etc) and my next step is getting new spark plugs.

I read the "safely modding.." thread and did some research on getting a cooler thermostat along with cooler plugs. I read that it isn't wise to change the thermostat to a cooler temp on newer cars.

What do you think? Should i just leave the stock thermostat, and get stock temperature plugs?

Hmm... thanks, that's what I figured. I don't have any mods other than the open cone intake and pipes in place of the mufflers lol

And if I remember correctly that you would have to do some tuning with your PCM for the thermostat to actually run beneficially.

Originally Posted by csssaint12

And if I remember correctly that you would have to do some tuning with your PCM for the thermostat to actually run beneficially.

yup. the car still runs hotter because the radiator fan turn on temperatures arent set right.

Yea all i have is a 3"DP homemade intake tuned pcm and 180 stat i had copperpacecar hook up hptuners to test for knock i had about 3* at WOT in high RPMs i put a 160 stat in(as per his suggestions) lost 2 miles per gallon but she is running like a champ due to not loosing timing

You can't run 160* tstat on an 04+, It'll throw codes.

Originally Posted by klj5022

Yea all i have is a 3"DP homemade intake tuned pcm and 180 stat i had copperpacecar hook up hptuners to test for knock i had about 3* at WOT in high RPMs i put a 160 stat in(as per his suggestions) lost 2 miles per gallon but she is running like a champ due to not loosing timing

nothing you just said makes sense.

Thanks everyone.


Also, what spark plugs would you suggest (brand/material) ?
EDIT: Nevermind, recommendations for spark plugs are given in the Safely Modding Your 3800 Powered Car!! thread

Originally Posted by klj5022

Yea all i have is a 3"DP homemade intake tuned pcm and 180 stat i had copperpacecar hook up hptuners to test for knock i had about 3* at WOT in high RPMs i put a 160 stat in(as per his suggestions) lost 2 miles per gallon but she is running like a champ due to not loosing timing

the only reason you dont see knock is bacause from the factory, the knock sensors dont turn on untill ~175. so if your car never gets that warm or you havent lowered the knock sensor turn on point, your car is still knocking, you just dont see it.