This procedure is the same for 4.8/5.3/6.0L LS1-based engines.

Probably best not to do this immediately after a long drive . Don't burn yourself.

The t-stat housing on these engines contains the t-stat itself, hence the elevated cost of replacement t-stats:




Locate the t-stat on the front of the engine:


Place a catch pan under the truck. If you use a clean can, you can reuse what you spill. Loosen the hose clamp and remove the hose. The factory use glue here, so be prepared !!! It was tough to get off... Aim the hose for the catch pan !!


Remove the two 10mm bolts securing the t_stat housing. It may or may not fall right off, so be prepared to catch it.


Inspect your o-ring if the new stat doesn't come with one. Replace it if it's hard, has cracks or you have high mileage. A cheap part, better safe than sorry.

Reassembly is simply reversing the steps. Don't over torque the housing bolts !! I don't have the factory specs (I'll get them ), but I'd say no more than 15~25ft/lb, but I'll get a shop manual here soon...


Top off the cooling system. If you kept your old stuff clean, carefully pour it back in. If not, either get some pre-mix at the parts store, or top it off with distilled water in more temperate climates.

Start the engine and inspect for leaks. Let it get up to operating temperature and recheck the coolant level.

And you're done.

Thanks to QSClub member danthaman for allowing his truck to model for us !! This hottie will be showing us more soon !!!!

This message has been edited. Last edited by: MrQuadrasteer,

Okay, do you think it would work if I kept a summer t-stat and a winter t-stat and switched between them? I mean, are they reusable?

And, where do you get them? It sounds like a model specific part, so maybe the stealer and not Murray's...

They should be reusuable, and they're O-ringed, so that simplifies things.

I'm guessing Murray's is an auto parts house ?? The dealer won't have the different temps (I doubt), but if you can't find them local, I know our sponsor TByrne Motorsports has them.

As far as model specific, yup, all the LS-x based motors (that would be all of us !!!) should have the same style t-stat.

Factory temp is 212*. I've seen 160*, 180*, I have a 186*, and 195*, plus the stock temp.


Something that seems to get lost in the shuffle that is worth doing is the throttlebody bypass. For you Northern guys- DON'T DO IT !!!!! Wait for summer to do it !! But we Southerners can do it year-round. Look in the tech section, but basically there is a coolant line that runs thru the t/body. All you do is get a (I think) 1/4" hose splice and connect the two ends. That's it. Should help cool the incoming air. Probably not worth anything you'll feel, but every little bit helps

Useful info as usual, - thanks!

Do you need to reprogram the PCM with at lower temp thermo?

I never thought to ask. Thanks for bringing that up!

What do you think about this Mr. Q or Lyndon?

YES- you MUST recal the ecm for different temp t-stats.