Motor not getting hot?

This is on a 87 4.0L closed system.
Ive searched around but all Ive seen is people with overheating problems. The temp gauge shows no signs of heating up at all and doesnt even move. Also the upper radiator hose to the radiator never get warm.The heat works great also. I thought the t-sat was stuck open so I replaced that and still no change. The fan is always on whenever the motor is running. The thing is the Jeep never seems to overheat at all. I let it idle for 1/2 hour and it did not overheat at all. The radiator has a small leak but its not spitting out fluid at all, just a dribble here and there. What the hell is going on with this thing, Im stumped.

new thermostat. That's prob where I'd start for as cheap as it cost to replace that. If you live in a cold area, and are waiting for your jeep to warm up to operating temperature and it's not getting there it's probably because your thermostat is stuck open. I replaced mine this fall, quick fix.

not heatin

Takin a WAG here temp sending unit........bad guage........water pump
Like I said,these are Wild AZZ Gusses

bttt

Heep said:

Ive searched around but all Ive seen is people with overheating problems.

The temp gauge shows no signs of heating up at all and doesnt even move.

Also the upper radiator hose to the radiator never get warm.
The heat works great also.

Click to expand...

You contradict yourself. You get heat, but your radiator hose isn't warm at all. I don't think this is right at all go back and check. obviously warm fluid is going into your heater core???, so some fluid has got to be warm.

i dunno, of course I don't know that much i'm only 20.

you said the gauge show's no signs of heating it up, but yet you can get heat. so your engine is warm and fluid is warm. I'd go with the other replies such as temp sending unit. I don't see how the water pump would be the suspect seeing how your jeep isn't overheating.

good luck find your problem

I have an 1984-made XJ, with the 2.5 lt engine. My temp gauge never registers anything higher than a bit after the blue zone. I tried new temp sending unit, new t-stat, new gauge, always the same. The engine though seems to be running fine, the water at the radiator is at around 80 degrees celcius, which should be about 190 F (I don't have a conversion available right now). If you ground the temp sending unit wire, the gauge shows full deflection.

I suspect the quality of the wire going to the gauge from the sending unit, but I just do not have the time to take the dash apart again, to verify it. So I just accept it as it is, and pray that if it ever overheats, the gauge will show so.

Rgds
----------
John

Maybe it wouldnt be a bad Idea to, at least temporarily, hook up a quality aftermarket temp guage. The stock guages have never really been known for thier pinpoint accuracy.

Not sure what to tell you, none of the motors should really get hot. Mine has a blower motor, and front & rear wiper motors and none of them get hot. :moon:
If you mean the ENGINE then I'd suggest a good set of mechanical gauges as none of the factory gauges in any vehicle are very acurate... You can pick up a set of 3 Sunpro mini gauges directely from the mfg. for real cheap ($9.99)here -
http://www.actron.com/ just click on "Garage Sale" on the Sunpro side of the site. I didn't install any in mine yet but once I get the stereo in I'll figure out where to mount them.... any ideas guys?
Mike B.

You lads are all missing the point that he says the upper radiator hose doesn't get hot. It should. If it doesn't, I would suspect either a faulty thermostat, air in the system, or a faulty water pump (but the water pump would likely result in overheating).

Don't know if this would be the total cause, but you state that the fan is always on. If you are refering to the electric fan, then it should not be on at a low temp. Unless you also have a/c on. The excess cooling may be contributing to your situation. May be faulty temp. sensor in radiator. Just a thought. What do you guys think? Don

PS: Also, if you have an xj with closed system that has a leak, and doesn't heat up, I would contact Guiness Book of World Records. lol