Pnguyen7

Good?Bad? I wanted it to run cooler but now its running around 150-160 used to run 190-210

ol"blue

The computer controlled systems on these Jeeps call for a 195* t-stat. I always use what is called for by the FSM.

Programbo

I have been trying for years to eliminate some odd TPS problem which at first seemed to be related to my Jeep reaching a certain temp so I changed from the 195 to the 180 in an attempt to cure it (It didn`t)...I noticed no change in operation from switching the thermostat....As far as the Jeep calling for a 195* stat, if you go on the Advance Auto website and search for the correct t-stat for this year/model/engine Jeep it shows both the 180* and 160* as optional replacements so there must be some reason those are considered as acceptible replacements...Maybe usage or location?

Mike1998XJ

Did you check your gas mileage with the 180 stat for a comparison to the 195?

4.3L XJ

You can make a number of tstats fit. However if the temp is too low, particularly with a 160 degree stat, you will run rich and your milage will suffer.

Mike1998XJ

Correct, that's why I asked 4.3l...
Mike

nojreyd

I tried a 160 t-stat. You will run cooler (I top out around 180 usually), but your mileage will definately suffer (I lost 1-2 mpg). I switched to the 180 t-stat and things improved, but my temp cam back to that 200-210 range up top. Thats where the engine is designed to run. Also your emissions will probably be much worse with the colder t-stats in (they dont have checks in my state).

Programbo

Actually never thought of that angle..I do a lot of long weekend trips up to the mountains so I can get a fairly good estimate of my current MPG just on one of those..I'll make sure to do a check next time...If my MPG dropped I'll switch back to the 195* since changing the tstat didn`t do what I wanted anyway.

Pnguyen7

i live in ohio no smog tests.hotter somedays but cooler on most.should i go back to 195?

4.3L XJ

Yes

Mike1998XJ

X2
The Engineers who designed your system did a lot of testing on this. Trust in them.

ol"blue

I agree.

98 JeepJeep

I would check you Temp sender......sounds like its shot. dont forget the guage too.......

Programbo

OK..Took two long trips down into Virginia over the weekend and back and also a side trip up over the Blue Ridge Mountains to the casino in Charles Town, West Virginia (Came out $220 ahead)..Anyway, after driving about 350 miles I found I averaged 18.02 MPG which is actually UP about 1 MPG over what it was before I switched from the 195 to the 180 stat

Pnguyen7

yea mine runs around 170 180 i haven't had to much trouble