engine not warming up?

[scoutinkeith]

93 wrangler w/4.0L engine,
at first, I thought that the temp guage just wasn't working, so I picked up a new mechanical temp guage, and installed the sensor for it in the heater hose coming off of the water neck, just a few inches away from the stock temp sensor. the new guage works, but according to it, the engine is only getting up to about 130*. I just put in a new thermostat, so I know that's not the problem, but I can't figure out why it's not getting any warmer.
any thoughts or ideas of where I should look next?
I am thinking of moving the new sensor to the upper radiator hose, but after driving it for a wile last night, even the upper radiator hose was cool enough that I could hold it with bare hands, so I'm not sure if moving the sensor will make any difference.

what else could cause the engine to not warm up?

[Ray H]

Originally Posted by scoutinkeith

93 wrangler w/4.0L engine,
at first, I thought that the temp guage just wasn't working, so I picked up a new mechanical temp guage, and installed the sensor for it in the heater hose coming off of the water neck, just a few inches away from the stock temp sensor. the new guage works, but according to it, the engine is only getting up to about 130*. I just put in a new thermostat, so I know that's not the problem, but I can't figure out why it's not getting any warmer.
any thoughts or ideas of where I should look next?
I am thinking of moving the new sensor to the upper radiator hose, but after driving it for a wile last night, even the upper radiator hose was cool enough that I could hold it with bare hands, so I'm not sure if moving the sensor will make any difference.

what else could cause the engine to not warm up?

The thermostat is probably stuck open. I cant think of another reason the engine wouldnt get warm. Did you test the t-stat before installing it? I always boil mine on the stove before installation just to make sure it works correctly. Matter of fact, I just did this for my XJ last week. The old t-stat was opening when it should at 180 but wouldnt close until about 150 so the engine was running just above 150 after its initial warm up. 150=very little heat or defrost.
I would pull the t-stat back out and stove top it. All it cost is a few minutes and a new gasket to find out.

[scoutinkeith]

yep, just put in a new T-stat, and I did "boil test" it before install.
my only other guess is that the radiator is to big, the guy I bought the jeep from said that he had recently had a new one put in. maybe I'm thinking wrong here, but even if the radiator is to big, shouldn't the temp come up to 109*(where the T-stat opens) then drop off? I would think so, but the guage only comes up to 130*, and stays there.
I'm going to try some cardboard in front of the radiator to see if that helps, but if not, I don't know where to look next.

[Ray H]

Originally Posted by scoutinkeith

yep, just put in a new T-stat, and I did "boil test" it before install.
my only other guess is that the radiator is to big, the guy I bought the jeep from said that he had recently had a new one put in. maybe I'm thinking wrong here, but even if the radiator is to big, shouldn't the temp come up to 109*(where the T-stat opens) then drop off? I would think so, but the guage only comes up to 130*, and stays there.
I'm going to try some cardboard in front of the radiator to see if that helps, but if not, I don't know where to look next.

If your t-stat checked out, I dont know then. I think you are right about the radiator. Ive got an aftermarket 3 core in my wifes TJ and my XJ and the t-stat still maintains the engine at the proper temp. If you do have an oversized rad, you should see the temp go up to 195 then drop down a few degrees as the t-stat opens and cool fluid rushes into the engine, then go back up as it closes, and keep cycling like that, but not get really cool.

When you had the temp sensor in the heater hose, the heater was on right? Let me know how it does in the upper hose.