Hi all, new to the site.
Just wanted to pass along a observation.
I installed a 160 thermostat about a month ago and it is working pretty well. I live in Louisiana and because of the predominantly mild environment I feel I am safe in my decision. I will continue to monitor it through the cold months though.
Anyway… I was driving to work and I received a warning on the computer that stated the A/C was disabled to protect the motor. Now I am assuming because the computer recognized that the engine was not reaching normal operating temperature and it did this as a failsafe.
Has anyone experienced this or am I way off base here.

160 may be a bit cool for our cars. Is it throwing a code??

A 160 t-stat will cause that. You're better off with a 180 t-stat to keep the motor at the proper operating temp.

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Bright Red 2008 G8 GT

Mods: DRCUSTOMPARTS Center Gauge Bezel
Superchips ECM/TCM Tune- Volant CAI
Solo Axlebacks - HID's
Holden V8 Badges
My Website

What is stock on the GXP? Is it 198?

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K&N CAI/Flips Custom Headlights, Tail Lights, Reverse Light,Brake Light/Front STB/Magnaflow Exhaust

2008 Grand Prix GXP

It's a 195 so a 160 is way too low.

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Bright Red 2008 G8 GT

Mods: DRCUSTOMPARTS Center Gauge Bezel
Superchips ECM/TCM Tune- Volant CAI
Solo Axlebacks - HID's
Holden V8 Badges
My Website

i thought the tstat for the gxp was 186....i have the 160 and never have had any issues

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Only a memory
Pioneer Nav/Magnaflow Catback/E-Cutout/Poly MM/CAI/160*/TBS/STB F&R/Wrapped X-Over & 3'' DP/Flip Paint/XP5243 Atl. Plugs/10.4mm Taylor Wires/SSC

256HP/341TQ
14.05 @ 100.4 2.24 60'

I looked at the OE replacements and they say 186. I'd put the stock one back in and get it tuned for the fans to come on sooner. With stock tune it would get near the red before the fans would kick in 100%, now with the Overkill tune it stays under halfway. Also the ECM doesnt allow the fans to come on any lower than 192-195 I think, so a cooler t-stat doesn't do us much good.

Thank everyone for the comments…
One of the greatest problems I have with this vehicle is that it is so hard to find any manufacture information. It is a 08 and I am only able to find info on-line. Not a major issue but I have read that there are some minor tweaks that have been made to the 08 engine and computers that will not make it the same as say the 06-07. Specifically the DOD programming so modifying this thing has proven to be a bit tricky.
Back to the matter at hand. The vehicle has had an eng. Comp, and trans. Comp. tune done professionally. It has already been programmed to accept the lower thermostat. The fans are set to come on at 100% at 220 deg.F. They will increase 10-20% through the range respectfully. I am not having an issue with the vehicle overheating. The trans on the other hand loves to live around 200-210 deg.F. but I will be installing a trans cooler in the very near future.
I don’t feel that the 160 thermostat is too low especially for the very hot weather here in Louisiana, but that again is in my opinion and I’m sure there are people that read this post that are a lot more qualified than me.

-- Mon Apr 18, 2011 7:02 am --

Just for a bit of background of what has been done so far…
K&N cold air intake, GM heat soak reduction kit, Hogan downpipe, Magnaflow cat-back, Bosch Platinum Ir Fusion plugs, 160 Thermostat, Eng. and Trans comp. tune, All fluids replaced with synthetic fluids and analyzed by Blackstone labs.
I purchase the OT-2 Logworks from innovate motorsports to make sure all is running smooth while driving. That is a really nice piece of equipment that is relatively cheap!
It’s not much but it has made a world of difference over stock.