80 Econoline 351 5.8l engine overheating
 

Yesterday, I did basic service, changed oil and oil filter, spark plugs, spark plugs cables, fuel filter, thermostat and its gasket.
Afterward when I was driving I notice that my engine was overheating, what can be the problem?

Could be an air pocket trapped after changing the Thermostat........

Where is air pocket on that engine, a picture or diagram will be helpful.. I am still familiarizing that engine. Thanks

It's more of a procedure for bleeding off any trapped air, check YouTube and Google it. It can be very dangerous if you have never done it before, 195 deg coolant can take your skin off instantly............But since you have already driven it I would just recheck the Coolant level (cold) and see if it has dropped any and refill as necessary, it might settle out on it's own....maybe.

bleed out air
 

if it doesn't bleed of by itself, find the highest point of cooling system (temp sensor, etc). open system at that point, bleed air out until only coolant comes out. Good luck.,,,,jack

Great advice on the hot coolant---its actually much hotter than indicated since its under pressure---my guess is it approaches 245* or more. :eek:

I've always bled off the cooling system by first filling the radiator & block as much as possible. Start the engine, the level should drop as the water pump pushes coolant through the block. Refill coolant while engine is still running, replace radiator cap, sit inside the van and watch as the temp gauge rises. Now's a good time to turn the heater to High, blower motor also on High---warm air through the vents says coolant is at least circulating through the heater core.

The temp should climb slightly above normal operating temp then drop quite a bit---thermostat has opened and coolant is flowing---CAREFULLY and SLOWLY turn the radiator cap just enough to vent built up pressure. Once the radiator is under atmospheric pressure time to add more coolant, up to the recommended level in the radiator.

IF the level seems full raise the RPM's to at least 1500-1700 (helper) while watching the radiator level. Any trapped air will be pushed out because the water pump is working better, the level will drop slightly if air was present.

Raise and lower the RPM's several times during this step to make sure no more air is trapped in the block. Once the coolant level remains constant replace and secure radiator cap.

That should work for any of the older engines---always has for me.


HTH

You haven't put the new thermostat in backwards?