I've seen a few forums about 180 vs 190 thermostats and I just wanted to post a little comparison of the gauge before and after the thermostat swap.

Before:

After:

The first pic (180) is about as high as it got for a 100+ degree day. In the cooler nights on the highway it barely made it over the "C" mark. The second one (190) looks a little bit higher but in stop and go traffic (I have no AC) it gets closer towards the middle in which the engine fan kicks on and lowers the temp back to about where it is now.

Hope this helps anybody when it's time to replace a Tstat. I just think that it runs too cold with the 180. The 190 seems more appropriate and it is an OEM dual stage Tstat from 22REperformance.com.

 

Good experiment. I plan to do the same with mine as it gets colder out. I have the 190*F(88*C) thermostat now and plan to go to the 195*F(90*C) stat.

 

It would be interesting to do a fuel milege comparison between the engine operating with the different thermos' installed.

To get a good test, the truck would have to be operated repeatedly over the same course.

 

I could do it with mine. I track every tankful and my commute is very repetitious. I tracked with the EGR blocked. Result?, no change. 22mpg highway.

 

I can do that. With the 180 I got about 22-23 MPG in my '89 pickup 4x4 5 speed. That's with about 80% highway driving and 20% city. I drive about 250 miles a week and fill up every weekend. I'll report back once I get some results with the 190.

 

I have a 180 degree in my 93 22re
I haven’t noticed any difference at all.
I initially decided to try it because I couldn’t stop it from pinging on regular. The Texas heat was also a factor. So no real difference noticed. I do have my timing advanced about 8 degrees. It pulls great off idle but falls off around 4000rpm. I get about 20-22 mpg with 4.56’s and 31’s. Yes I factor in the speedo error.

 

It looks like such a small change on the guage. One could almost discount it as bumping the sensor leads. Ten degrees at this location of the sensors resistance curve is only a few items of milli ohm.

 

So I’ve ran a 180 thermostat in my 1990 Toyota pick up 22 RE for 25+years and my temperature gauge has always been at your 190 position in the last year my 180 thermostat has been at your 180 position I have no idea why my 180 thermostat and I know for a fact it was 180 was doing that for 25+ years

 

I went from 190* to 195* and the difference was barely noticeable on my temp gauge. Arrow still points at the leg of the “P”.

 

I'm impressed at the mileage numbers people report. I've tracked mine since new, and never seen regular MPG as high as reported in this thread.

With mostly in-town trips, I see a bit under 16MPG, and with a mix about 17MPG. The below chart is across the last 24 years. Fuel is California mid-grade, and tires have been Cooper AT3 30x9.5R15 (2012) kept around 32-35PSI. Engine is unmodified 22RE with around 198k now. No step changes have been seen when changing spark plugs and air filters.