Motorhead-47

I have a 2009 LS3 and am in the middle of trying to install a Motorad 160 Thermostat that I bought from one of the forum vendors. This thermostat does not fit snugly in the thermostat housing like the OEM did. When measured, it measures out at 2.1" vice the 2.2" of the oem thermostat at the flange where the o-ring/gasket attaches. I am afraid this thermostat at 0.1" smaller in diameter is not the correct fit for this car. Does anyone else out there have experience with the new LS3 and changing a thermostat that could chime in with their experience? At the moment I think this is a no-go but would like a second opinion.

OEM Thermostat..see how snug the o-ring fits the housing


SLP/Motorad 160 Thermostat...see all of the gap around the o-ring?

Motorhead-47

Note to all...I just learned thanks to outstanding vendor support at SouthernCarparts (Jim) that the 2009 LS3 thermostat housing is different from previous years. Do not buy a 2005-2008 thermostat and expect it to fit your 2009 C6 LS3. SLP knows about the problem and will hopefully have a 2009 part in the next 30-45 days or so.

Nd4spd2

Good to know, thanks for posting. Nice catch. I just had my second 160 stat go bad in the past year. First one worked great for a few months then started running hotter and hotter. I put a new one in and it was fine for a few months and now it's opening at 145 degrees so engine temps vary wildly with outside air temps. I just ordered a different brand one this time and hopefully it will last.

TLK

Thanks for the heads up. I wouldn't have guessed it would be different, and now you've saved me the trouble. Maybe you can post again when the correct part becomes available.

Motorhead-47

Jim promised to call me directly as soon as he has it available. He has also updated his website to reflect what we learned today.

I find it surprising that I'm the first guy on this forum to try and stuff one of these in a 2009 LS3.

Anyone want to buy an ever so slightly used, never installed 160 degree thermostat? 2005-2008 fitment only!

Motorhead-47

For those that are interested SLP now offers a 160 thermostat that fits the 2009 LS3. Part #100229

USAF-Vette

What brand? Is it reliable?

Thanks for all the good info.

Rick

Motorhead-47

SLP markets it as an "SLP Thermostat"...like all of their others. Probably manufactured by Motorad. Reliabilty?...probably the same as all of the other Motorad thermostats which has been good. Being new there is no reliability history on this particular part number.

If you've ever done an LS2/3 t-stat swap you'll quickly notice the replacement doesn't appear to be nearly as robust as the OEM GM thermostat..for whatever that may be worth.

http://www.slponline.com/view_product.asp?P=100229

RBLUVETT

Maybe this is the reason that mine (09) is leaking (see yesterdays post) I had mine replaced in February in Florida by a well known tuner here on the forum. I'm not sure what brand of thermostat was used. I ordered a new o ring today, but that may not solve the problem.

Motorhead-47

To the best of my knowledge no one (until now) has started building a thermostat for the 09 LS3. From what I can tell that thermostat isn't going to be available for another 10 days or so. (Jegs and Summit both show a ship date at the end of the month).

So...it's very probable that the "well known tuner" installed a thermostat that isn't meant for your application. When you pull the cover to replace that gasket/o-ring take a look at the overall fit of the thermostat in the housing. If it isn't a very snug fit then you have the wrong thermostat.

TLK

Thanks for the follow up. I ordered mine right after you posted the alert this morning.

davekp78

Have you guys measured the diameter of the thermostats themselves, with the gaskets removed? May be just a different gasket. If so, reuse the OEM gasket.

Motorhead-47

Yep....I measured it and mentioned it in the original post. The actual outside diameter of the earlier t-stat is 2.1" and the 2009 stat is 2.2". It isn't a gasket issue. If you try and install your original OEM gasket on the earlier thermostat it practically falls off.

Nd4spd2

I wonder why the hell they changed the size on the 09. Seems ridiculous. I'm on my third stat in a little over 1 year. I agree the aftermarket ones aren't as robust as the original.

RBLUVETT

I have tried to contact the "well known tuner" by phone and email; the phone is always busy, and he hasn't answered the email. Holy Cow, what else can I do.

08VRZ06

Wonder if a 2008 LS3 Thermostat Housing will bolt in place of the 2009?

Mark

Motorhead-47

You can either reinstall your oem thermostat or place your order with SLP, JEGS or Summit for the right part (assuming you don't have the correct one installed). What's another $50.00 right?

You bring up something that is a personal heartburn of mine...guest appearances to tune your car in a parking lot of a hotel, convention center, etc. using seat-of-the-pants tuning techniques and nowhere for the customer to turn to when something isn't right. Compound that with the fact that your ECU is locked preventing someone else from unwinding the mess.

IMHO "Drive-by" tuning is a poor choice!

Motorhead-47

Good question...but now that we know there is a difference it's just a matter of installing the right part correctly.

RBLUVETT

The "tuner" has contacted me and thinks the wrong thermostat may have been installed when the tune was done. He is sending me a new 09 stat. I will, of course have to install it myself.

Motorhead-47

It is an easy install...2 x 10mm bolts and whatever mess you create when you drain/refill the radiator. Pay particular attention to the "nub" on the gasket and it's corresponding notch in the thermostat housing.