In the summer my ( 96 SE) t-stat goes a little over 200 deg. almost all the time. Is this need for concern? Should I replace the t-stat with a lower temp. one (maybe 180 deg)? What is the stock t-stat?

I've had the car since 1997 and the t-stat has never been replaced. In the winter it is a little below the 200 deg. mark and I have plenty of heat. Car has 122K miles.

Edited to add I just read an interesting thread here that discusses the diff. between 180 & 195 deg. t-stats. Let me modify my OP a bit: is it normal for my car to run over 200 deg. in the summer?

TIA,
Phil[/b]

Considering your conditions in Boise, I'd normally say hold off on the 180 until spring. Something is pointing me in other directions for a solution right now.

Do you have DEX? Or conventional coolant? What mix? What does it look like? Has it been tested recently? What does your overflow bottle look like? Scummy? Remove the radiator cap. Do you have any sludge buildup evident?

If all of the above checks out ok, I'd go ahead and install the 180. In the meantime, you might want to PM Hans (member here who lives near you) a link to this topic to get his opinion on thermostat choices for your cilimate.

For what it'* worth, I run a slightly drilled 180 year-round in Corvallis, OR in my daily driver in Oregon. I would assume based on that, you could run a 180 in the winter with a tiny bleeder hole drilled in the rim where you are.

My 96 did the same thing recently with the original thermostat. when they wear they go to the hot side, not like the old ones years ago.
Put in a stant and it stays below the 200 line.

www.intense-racing.com and ZZP both sell 180 degree thermostats that have larger openings and longer stroke (more flow) than Stant thermostats.

Thanks for the quick reply. I use Dex-cool by Prestone. About a 50/50 mix. It tests fine with my home tester. Under the rad. cap does NOT look scummy and neither does overflow bottle. A/F replaced in 8/2005. At that time a local mech. did a headset job/resurfaced heads/ground valves. A week later the same problem reoccurred-radiator water/fluid disappeared (white smoke out the tailpipe) and I went back to the and he said he should have replaced the UIM, etc (and he did at "cost"). Not too unusual a problem with that engine I guess. But the last two summers the engine still gets hot-over 200 deg.

Should i not be using DEX A/F (the orange stuff)? Do any of the local stores sell a good t-stat (NAPA, A/Z, Schucks)? I looked at the Intense one and it'* about $18 w/shipping. Is it worth it?

Phil
I'll PM Hans. Thanks.

id say (depending on weather and other factors) its really nothing to worry about till it gets over 220

when I think overheating I'm thinking the car is getting quite a bit above 200.

Does it go above 200 when sitting in traffic?

Some will say you will loose 1mpg because the engine is less efficent, some will say dropping to a 180 has no impact at all on fuel economy

I personally run a 180* stat all year round and have my fans turn on and re-programed the fans to 185 on low speed and 195 on high.

It seems as if your car is operating as designed, it should constantly be right around 200.

Dropping to a 180 is more important when you are concerned about pre-detonation (aka in terms of a supercharged car which has a smaller pulley on the blower)

Thanks guys, I guess I won't worry about 200 temps. but will consider changing to a 180.

What A/F do you recommend on my next change? Dex-Cool seems controversial.

Phil

Phil,

You're right, Dexcool is controversial. I have ran green ethylene glycol for quiet sometime now. No problems.

I recommend G05 spec "mixes with any color/type" coolant. This is usually a less intense greenish yellow in color and is sold everywhere including Wal-Mart.