Hi.
Need to pick someones thoughts here.

I have a 92 E250 with a 5.8l motor and it will not reach operating temp. Matter of fact it will barely make it into the "normal" range. Coolant temp sensor and thermostat were replaced twice and it's not a malfunctioning gauge because the heat that comes out the vents is barely warm as well.

Any help would be appreciated.

 

What temperature thermostat did you put in? It could be that it's opening too soon, did changing it make ANY difference, good or bad?

 

I believe it's 185, stock. It didn't change at all.

It acts like it's stuck open for sure. that's why i changed it a second time.

Puzzling to say the least. Also no difference in temperature whether the vehicle sits idle for 30min or driving down the road.

 

After a long drive, check the thermostat housing & the radiator tank near the upper hose with something like this:

<-Click it

The gauge isn't calibrated; the t'stat doesn't control the engine temperature; and the heater is a different kettle of fish.

 

Just for ****s and giggles I checked it with my IR thermo. it's 117 just as i expected.

Any more suggestions?

 

What are you using - cheap house brand thermostats? I'd either get one from the dealer or get a Stant.

Pull the stat and use the hot water on the stove and thermometer procedure to see what temp it's really opening at.

 

A stant

 

I did that with the old therm and it opens at 187, says my fluke 61. So it's right there

 

Exactly WHICH spot did you check - the t'stat, or the radiator? And how far had it been driven?

The engine might be running rich, which would make it run cool. Is the tailpipe black? What do the plugs look like? Is it storing any codes? Is there an exhaust leak near the oxygen sensor?

 

Both.
A few miles, it cools no differently in this case whether its driven or sitting.
No black pipe, plugs are caramel and no codes and no exhaust leaks.

 

Anyone have any other suggestions?

Thank you

 

All I can say is it's mighty strange. Any engine will create heat from the burning fuel even on the coldest day. I suppose you had your heater turned on full blast. That would take away some of the heat, but still not enough to keep the engine from reaching normal operating temperature with no circulation through the radiator.

Here's my suggestion: Remove the radiator cap before starting the engine, this will probably cause some mess from spilling over. Turn the heater off and start the engine. Carefully watch for circulation of the coolant while you let the engine idle for five minutes or so. You should get no circulation until the coolant gats close to 180*, but your heat is being dissipated somewhere.

One more thing to check: When your t-stat housing reaches the 117*, The coolant shouldn't be flowing through the radiator yet. So the coolant should be cool or cold to the touch. Also check all points of the radiator as well as the bottom radiator hose close to the radiator with your IR thermo.