Well, it seems I'm having a bad under heating problem. I just changed my radiator yesterday along with the t-stat, hoses, and a flush. After the flush I idled and burped it for a while to make sure I didn't get any air pockets. Now it runs at just over 100 degrees (probably 120-140) on the freeway. In town it gets up to 180. The temps where I'm at are around 20. When I let it sit and idle I get up to 200. I don't think my gauge is bad because it worked fine before I did the work. I also don't think it's an air pocket because the heater is pretty cold too. Could it be my t-stat even though it does warm up (the problem only seems to come up on the freeway.

 

What size T-stat did you put in? it should be a 195...Tj

 

Oh yeah forgot a couple things, sorry. It's an 87 Cherokee with the 4.0l. The t-stat I put in was the stock 195*. It might have failed open but I'm not sure. Also I put in a normal 1 rad.

 

Try this burping technique...Tj
http://www.lunghd.com/Tech_Articles/...BurpAirMod.htm

 

Man every time I check what people say here I remember something else I forgot. It's an 87 but the PO changed it over to the newer open cooling system. So I have a radiator. I say there and burped it for like a half hour. I guess there could still be air. The overflow tank has a hose at the top for overflow that opens to the air. So there is a path for air to get out (if that makes sense).

 

Still air in the system or a partially stuck new thermostat (it happens). I buy my stats directly from Jeep and the Stant SuperStat is also very good. No name stats are usually junk. 195 degree only.

 

I put in a napa brand I. Guess I might have to change it out. Idling I seems to get up to operating temp quick and stays there but when I start driving it drops quick. In the summer (before the radiator started leaking) it would sit right at the first large hash mark after "100". Dunno how hot that really is. How bad is it to run this cold? Just so I know how soon I can fix it (like do I need to do it today or can it wait till tomorrow.

 

Don't see how it could actually run that cool in summer.....bad sending unit/wiring/elec connection maybe.

 

Well it ran that cold while driving on the freeway. It would heat up past 210 if I was say stuck in traffic. And when I was low on coolant from the leak the temp would climb. It seems to work when I am at idle (temp goes up). I think I might go ahead and swap out the t-stat anyway. Hopefully not too much coolant will leak out lol.

 

Your gauge may be indicating 120-140 but it's not ACTUALLY running that cool in summer, no way. I'm just guessing/thinking whacked temp readings.

 

Gotcha. Now should I be able to hold onto the upper hose after I've been driving it?

 

This time of year, maybe....summertime, not.

 

Yea. I tried touching the t stat housing and that was a no go lol. There's a hole in the plastic box that houses the heater so that could be a the problem with not getting a lot of heat.

 

Got access to one of those point-n-shoot infrared thermometers?

 

Possibly were should I take the reading at