I talked with a GM engineer about all of us guys switching from 195 to 180 stats. He said that it is not a good idea.

1. It will cause the engine to choke and shoot in more fuel than is needed, clogging up the emmisions system, creating lots of carbon and burning more gas.

2. Normal operating temperature for 3800s is 200-230. The engine needs this temperature to properly burn fuel and pass emmissions tests. No, running the engine this hot does not at all hurt the valves in the engine. He did say that he replaces alot of plastic plenums on these cars. He said that GM is currently replacing newer plastic plenums for free. GM is under a lawsuit for these plastic plenums.

My mechanic said the same thing. I ran a 180 T-Stat in my Jeep for many years without any problems, but I also see the other side of the problem.

My solution: Kept the 190 stat in the Bonne and just did a pro-active maintenance replacement of the Upper Intake with the Dorman unit.

Lower intake temps=better power and less breakdown of oil. I get 29mpg on the freeway at 70mph with my DRILLED 180.

GM has instructions to discourage the use of 180'*. We also have had nobody running 180 have any problems passing emissions.

The 180 is especially important for the 95-99 non-supercharged cars with the failure-prone plastic upper intake. Cooler intake temps may help prevent those problems.

There are literally THOUSANDS of 3800'* out there running the 180 with no problems.

Bill didn't the 99s come with a 180 from the factory? Or was that a false rumor?

No they all came with 195f.

I have run the 180 drilled for 2 years and have no issues or problems to report after 50,000 miles.

I had to explain to my dad that it is better to have a 180. He thought it was a good idea. But for some reason, a lot of auto parts stores around here don't carry many 180s for our cars.

When you see these "perfomance" thermostats, like the Hypertech Hyperstat, or ZZP'* 180 Drilled Stat, is what you get at Autozone/Advanced just about the same thing? Are those purchased at a retail store "drillable"?

Mine is a Stant, too, and I drilled it myself. I can't see paying those 'performance' prices for an identical unit made by the same company.

Great info on thermostats.
I guess the mileage numbers tell it all.
Still trying to fine that sweet spot that will improve my 96 numbers.

I just dropped to a 160 for the summer. Still trying to combat some KR so im keeping the engine cooler. I did not have any problems with my 180.