Engine not reaching normal temperature and barely any heat. HELP!

[snake]

HAS to be the thermostat period. That sucker should shut down until it heats up and not allow any water flow until it does. Try clamping the rad hose closed and see if it heats up- just don't drive it that way it should overheat pretty damn fast...

 

[kimcrwbr1]

Nothing is leaking....

Be sure and let us know if you figure it out. You didnt happen to drill a hole in the t-stat to burp it. Take the upper hose off the radiator when it is cold there should be no coolant coming from the engine unless the stat has a hole in it.

 

[strvger]

any reason to think the temp gauge may be somewhat at fault? mine was reading cold, i had heat, pump, thermostat, etc. all fine. gauge crapped out on me and i had to get an aftermarket. just a thought.

 

[RustedRanger]

Thats what I was thinking strvgr...if the heater is working fine and its not running crappy then it could easily be the gauge. I've read here at TRS that the stock gauge is bad about being wrong. Summer before last my fan clutch went bad and the gauge only went to about halfway up "Normal" and it started running bad from getting too hot. It wasnt a pleasant drive to the junkyard in 80+ degree weather with the heater on full blast lol

 

[colby450xc]

Be sure and let us know if you figure it out. You didnt happen to drill a hole in the t-stat to burp it. Take the upper hose off the radiator when it is cold there should be no coolant coming from the engine unless the stat has a hole in it.

The thermostat I removed already had a strange valve/hole in it. I didnt really look to see if the new one did. I changed the old one out when the truck was cold and plenty of coolant came out of the motor where the stat came out, and the thermostat housing itself.

 

[Big Jim M]

The one with the "crappy hole" in it is the STOCK one from Ford. The hole goes to the top when installing it. THAT hole allows air to escape while filling. There is a small steel ball inside the hole that holds pressure as the engine heats allowing the thermostat to work properly.
The FORD one is the only thermostat I will use in these engines. They WORK!
These little trucks are a bitch to get filled with coolant PROPERLY! Most armchair mechanics never get ALL the coolant in their rides the first time they attempt to refill them.
I'm betting 99.9% of our head gasket and head failure is from low coolant.. I am lucky to have a slopeing driveway that allows me to make a good refill at the first attempt. However if I don't turn the heat to high and allow the engine to run with the radiator cap off till reaching temperature, even the slopeing driveway doesn't allow the system to get completely full..
Big Jim

 

[colby450xc]

I might be going to pick up a motorcraft thermostat then. In the first 4.0 I owned a had to replace the thermostat a couple times until I finally went to ford. I should have done it this time also. I asked for motorcraft but it would have been a day out. I might as well have just waited. I did try filling a second time, this was on level ground, and as the truck warmed up the coolant just started slowly to rise out of the filler neck and started spilling.

I wish it wasnt such a pain in the ass to change the thermostat, i need different size sockets or it sucks in that tiny space. Does anyone remove the serpentine belt when they do this? I notice the tensior pulley is in a terrible place or I would have removed the belt the first time.

 

[Dee907]

i would flush your system and start new and do a 50/50 premix of coolant and you should be good to go