Archived 12 valve engine won't warm 140 all the time

[CodySanders]

this truck sat for about 3 months everything fine when parked. im on a trip to go to utah and the truck just won't warm up. the engine temp is at 140 and stays there. usually it runs 180 consistantly. the heater barley works now and i don't know if it is the t stat or what please help. it is cold out side.

 

[p-Bar]

Gotta be the thermostat running wide open. put a good quality one like a Stant in their. Should fix the problem

 

[TBartlett1]

Had the same problem with my 1990, found it to be because I neglected the cooling system and corrosion was forming? After installing 2 new thermostats and the same problem reoccurring I decided a thermostat test was in order. I took all three thermostats into the house and put them in a pan of cold water and started heating them and recording the temp at which they opened, they all opened approximately the same time. I then cooled them under cold water and repeated the process several times; operation was consistent with all three. What I found when I was done with the test was rust particles in the bottom of the pan. What happened was that the rust became lodged in the thermostat affecting the operation. I then flushed the system the refilled with water and a system cleaner and ran for a hundred miles or so, drained and flushed a couple times then refilled with 50/50 problem solved.

I also bought a coolant filter fron napa and installed it and have had no problems since!

Hope this helps

Tim

 

[GCroyle]

Tool

I watched a guy trouble shoot a cold running 7. 3L with an infrared non contact thermometer, it gives you some good answers real quick.

 

[Missouri Mule]

Whats the out side temps if the t-stat doesn't bring the temps up you mite need to block some of the radiator off with cardboard.

 

[dfrey]

98 dodge 12 valve 140 on water thermostat not opening radaitor 60 deg no flow in upper hose have complet cover raditor pulling trlr with 79 dodge w200 and ploe on it still wont heattried s everal t stats

 

[Missouri Mule]

How is full is your over flow bottle? Is the radiator full? I had leaking radiator and if it got to low I would have no heat.
Did you get correct t- stat? Did you install it in the correct position ( temp sensor into engine)? Is it the old style t-stat that has the rubber thing that can get stuck into it?
What is your ratio to coolant/anti freeze to water?