I searched and found a previous poster asking the identical question I had..
Which Thermostat to get (online parts resources show an 87 & a 90 degree F)

He was answered with an unequivical, unqualified, and unexplained answer of 90.

But today, when reading through my owner's manual, I found that the specs specify the 87 for Turbo, and the 90 for NA.

I have the Turbo

Should I be following the specs, or is there some reason to ignore that and go with the 90??
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1995 850T Wagon 101k
1998 V70 GLT Wagon 85k

Unless you live in a very southern climate (US) where is never gets cold, use the hotter t-stat. Normal engine operating temp is about 93C and in colder climates, you want it warm ASAP to keep condensation from being a problem in oil and better heating. With a colder t-stat and short trips, it might never get to normal operating temps. You'll also have better emisions with fewer emisions, tune-up related problems with the engine running at normal operating temps vs running cold.
In over 25 yrs of being a tech, I've never used or installed a colder t-stat in ANY car but I'm in a climate where we have winter.
My daily driver car's a turbo too btw.

Wow Frank... great explanation! I really had to ponder and evaluate what you said.

I live in Santa Clarita, CA... near where the Stevenson Ranch fires were this month. Summers here can get really hot, with many days over 100, and a regular range of 82-105 in the summer. Winters here have some days where the temp gets perhaps as low as 30ish.

We live in somewhat of a rural area, so anytime we get in the car, we usually have to track at least 5-7mi min.


I liked the idea of reaching normal operating temps more quickly, reducing condensation risks, and minimizing emisions and tune up problems and all... but with our climate (although not Death Valley, Palm Springs, or Phoenix), and a 100k car with a Turbo, I am afraid we will be heat challenged more often than cold challenged.

Thanx for the explanation... it helped me understand the how and why, and gave me a good basis from which to evaluate my personal circumstance in coming to a conclusion!

Cheers
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1995 850T Wagon 101k
1998 V70 GLT Wagon 85k

My Turbo came with the 87c thermostat. Thats what I would use. Make sure it has the little bleed hole in it. Why are you changing it anyway? Have you had problems with it?

Mike
'95 850T

Yes... I explained it in detail in another post where I inquired about flushing, heater core etc. Basically, I have seen 3 specific instances in which the needle stayed around the 4 to 4:30 position rather than rising to the 3:00 position, and that over the course of the last 3,000 miles (I just bought the car used).

The last time this happened with the Temp guage, I simply pulled over, turned the car off, waited about 30 seconds, and restarted the car - to which the temp guage went back to the 3:00 position (a good tip for preventing excessive wear until one has time to make repairs).

Thanks for your input. It affirms my instincts... just wanted to check, 'cause ya never know!
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1995 850T Wagon 101k
1998 V70 GLT Wagon 85k

Yes... I explained it in detail in another post where I inquired about flushing, heater core etc. Basically, I have seen 3 specific instances in which the needle stayed around the 4 to 4:30 position rather than rising to the 3:00 position, and that over the course of the last 3,000 miles (I just bought the car used).

The last time this happened with the Temp guage, I simply pulled over, turned the car off, waited about 30 seconds, and restarted the car - to which the temp guage went back to the 3:00 position.

Thanks for your input. It affirms my instincts... just wanted to check, 'cause ya never know!
--
1995 850T Wagon 101k
1998 V70 GLT Wagon 85k