For the best info on the 2.5L engine check out all the Jeep forums the Jeep used the same exact engine for many years in a number of there autos.

The offical name is the AMC 2.5L 150 engine

 

More on the 2.5L http://en.wikipedia.org/wiki/AMC_straight-4_engine


And http://www.allpar.com/mopar/amc-25.html

 

Found a cool pic of the AMC 2.5L in a Jeep

CIMG4270.jpg

 

A 2.5L getting pumped up



3quarter_1.jpg

Driver_Under.jpg

Front_1.jpg

 

HEAT!!
We have heat! And you should of seen the gunky crap that came out of the hose.
Thanks, 98DAKAZ!

 

Ok glad things are good

 

I have a 2000 with the 3.9, and the same problem. It has been going on for about a month, and with the winter in Maine, it is no fun. I have replaced the thermostat, and flushed the heater core, and nothing came out except for clean antifreeze. The blower is blowing, and it does blow warmish air, but not the hot air it was just a few weeks ago. I also think the truck seems to be running about 10 degrees cooler than it was before, and have only been able to get it to heat up over 205-210 once. Should I be running a warmer thermostat for winter?

 

I have a 180 stat in mine with the mk8 fan mod set to 190 and it only comes on if i've been sitting, even when it was 29 outside with light snow on the ground. Heater was plenty warm.

The stock thermostat is 195 and I think the stock 16" fan is supposed to kick on at 210 and off at 205.

 

I would really like to get rid of that stock fan. The truck will warm up, just not the cab. The one time I got it to heat up over 205-210, I was parked on a steep hill for 10 minutes or so. I hate how the gauge is numbered, but I am guessing that mine is running around 180, maybe 185 for the most part, but of course, I could be wrong. I would love a set of digital gauges in there

 

mine isn't numbered at all. The fan kicking on/off is only way I know the temp.

I'm getting an Ultragage ASAP. Look it up, not bad for $60.