Hello all. I just got a FREE 92 F150 4x4 reg cab long box with the 5.0 automatic from my dad. It has 118k on it. The problem I'm having is I can't get it up to operating temp. The temp gauge moves between the L and the first letter, which escapes my mind right now. The heat blows warm at best.

I have replaced the thermostat (195 degree) and the coolant temp sensor, topped off the coollant level and ran it for an hour and checked the coolant level and it looked fine. The temp gauge goes down when I stop and rhe heat gets cooler, then when I'm cruising, the temp goes up and I get warm air. I installed the thermostat with the spring side towards the block.

I did not Burp the system though, I just found out 'bout that. Could this be the problem or is there something I'm missing? Any help would be great cause it gets cold here in Wisconsin. Thanks guys.

 

did you test the old thermostat, maybe you have a different problem than a thermostat problem. if the stat is 190 then the engine should run at 190.

 

No I didn't test it. What else do you think could cause this problem? I've been rackin my brain (even though I don't have much of it left after 16 years of marriage ) and I can't think of what else would cause this.

 

In a cold environment such as wisconsin, alot of guys put cardboard over their grille for the winter to trick the ecm into thinking its warmer outside.That would probably give you better heat. You may not even have a problem, these trucks just seem to run really cool.

 

The Putts above me stole my thunder about the cardboard.

Could be an air issue with the heater core, when the engine is up to what ever temperature it goes to, the top radiator hose, and the two heater hoses should be appx the same temp to the feel of your hand.

The gauge can be tested for function by unplugging the wire to the sender, open wire will show full scale, shorting the wire to ground will be at bottom scale. Memory is confused between fuel and temp gauges, 67 ohms will read at lower bracket or line at bottom for one and 85 is the same reading for the other. I guess thats useless info if the test box isn't available.

Check the three hose for nearly the same temp. That old mans trick has helped out more than one.

 

Thanks guys, I'll try it after work and post the results.

 

Could be a clogged heater core as well........takes a whole 15 minutes to change. Try the cardboard first and see if that helps.

 

Well, After I got home today, I checked the top radiator hose and it was hot. The heater hoses were also hot. The lower radiator hose wasn't as hot as the others,but still pretty hot.

I heard that these trucks had some kind of water pump issues, anyone think a faulty h2o pump could cause this?

 

go to the grocery store and get a thermometer from the kitchen isle...they have one that goes from -20 - 220 and put it in the rad while it is running to see what the water temp is in the rad...with the cap off of coarse...

it is cold as hell here and even on the 3 degree day I had plenty of heat and I run a 160 degree stat and when the engine is at temp the heat coming out of the vent in the truck is 130 degrees...roast me out on low...

so even at 160 degree running temp thats a 30 degree drop which is good...plenty o heat...



that means the pump and rad are working...the lower hose should be cooler...that is the return to the engine....

 

My 94' normally runs in the "O" to "R" in "normal" on my gauge during the summer, now it's around 29 degrees out and it won't budge above the "N". If the temerature outside is just bitter cold, it may just fine. You can do the old cardboard trick, which I'm getting ready to do myself! c'mon heat!