Replacement LS-1 Thermostat Does Not Fit
I checked around and verified I had ordered the right part and other similar aftermarkets were the same style and size. I then went to the local Chevy dealer and checked a GM replacement part and it was the same dimensions as the Powerstat too!
Last year the water pump was replaced under warranty and when I queried Service about it, they said a new thermostat came with the water pump. This thermostat instead of having a stamped cross bar that holds the end of the spring to thes upport legs/brackets, has a U shaped stamped bracket that goes all the way to the base of the housing. That makes the over all diameter of the guts of the thermostat small enough to fit.
The interference is maybe 1/8 inch (more or less) but is too much to grind off the outside of the legs/brackets to make it fit. The other alternative is remove the water pump and grind on the hole.
Is anyone aware of this change in design or potential problem?
It wasn't off by much so I made it fit. 3 years and no issues with leaks or anything like that. Everything works fine.
If you could tell me when you got your new water pump? I am still waiting on Chevy Tech support to call back but it looks like I am going to have to pull the pump!
But it does show the rest of the folks, that if you put in a new water pump, your old thermostat or any aftermarket thermostats will not fit without modification. Bad Move GM since they could have solved the problems by just drilling the hole 1/8 to 1/4 inch larger.
Yes, I thought it was a brilliant design also and wasn't pleased when I had to start grinding. It seems like the old or new style t-stats will still work though even though some of the material is removed. If in doubt a dab of rtv could be used along with the gasket on the t-stat.



