Overheating after New T-Stat

[Saltzman]

Hi everyone. I am new to this truck and just fixing all the million little things wrong with it . I have changed every fluid in the truck too. Today I replaced the T-stat with 195F new one. Flushed the coolant and replaced my temperature sender to get my temp gauge working again. I also replaced both lower and top rad hoses.

The truck now overheats and didn't prior to this. The top radiator hose is very hot. The bottom hose is cold and I have 0 heat. What am I doing wrong here?

The T-stat that was in it, was stuck open and I also had very little heat. I did not replace the rad cap but I highly doubt this is causing it to over heat. The clutch fan feels normal, maybe a 1/4 turn trying to spin it by hand.

 

[RonD]

Did you pull a heater hose at the firewall off while refilling the system?
Need to do that to let the air out of the engine while refilling

No heat in cab can be no coolant in upper hoses(heater hoses) and overheating is no coolant in upper engine

After it cools down and you can remove rad cap, do so

Then pull off either heater hose at the firewall and see if it has coolant in it, if not add more coolant until it starts to come out of hose and heater core connection


Some thermostats come with a Jiggle Valve, yes that its actual name, lol
It is a hole in the thermostat plate with a metal pin in it, this hole is to let out air that can get trapped behind the thermostat plate.
If it has one then thermostat should be installed with this hole at 12:00, highest point to let air out
If it doesn't have one then you do for sure need to pull of a heater hose to let out the air when refilling

 

[Saltzman]

Yes I did pull both heater hoses to back flush the heater core. I did not pull it off while refilling though. Ok I will try that and report back, thank you. Do you think the system just has air in it causing the overheating?

 

[RonD]

Yes, that would be my guess if heat in cab was not working and engine was overheating, both symptoms could be because coolant is too low and not flowing in upper engine

And just as a heads up, reverse the heater hoses at the firewall every 2 years or so, same as back flushing but for 2 years at a time, heater core will last longer

 

[Saltzman]

Some thermostats come with a Jiggle Valve, yes that its actual name, lol
It is a hole in the thermostat plate with a metal pin in it, this hole is to let out air that can get trapped behind the thermostat plate.
If it has one then thermostat should be installed with this hole at 12:00, highest point to let air out
If it doesn't have one then you do for sure need to pull of a heater hose to let out the air when refilling

This is the one I purchased.

https://shop.advanceautoparts.com/p/carquest-engine-coolant-thermostat-13379/5653126-P

 

[RonD]

Yes, no jiggle valve so no way for air to get out of upper engine as you refill it, thermostat is closed

Google: thermostat with jiggle valve images

You will see what they are

Not a big deal, but you do need a way to get the air out, which heater hose works fine for

 

[Saltzman]

Yes, no jiggle valve so no way for air to get out of upper engine as you refill it, thermostat is close

Google: thermostat with jiggle valve images

You will see what they are

Not a big deal, but you do need a way to get the air out, which heater hose works fine for

Thanks again Ron, super helpful. I will post back so others can see the solution.

 

[adsm08]

If I can't use a vacuum bleeder I usually fill the rad, then remove a heater hose, shove a funnel in it, and start pouring until coolant comes out of the heater core.

 

[kimcrwbr1]

Hi everyone. I am new to this truck and just fixing all the million little things wrong with it . I have changed every fluid in the truck too. Today I replaced the T-stat with 195F new one. Flushed the coolant and replaced my temperature sender to get my temp gauge working again. I also replaced both lower and top rad hoses.

The truck now overheats and didn't prior to this. The top radiator hose is very hot. The bottom hose is cold and I have 0 heat. What am I doing wrong here?

The T-stat that was in it, was stuck open and I also had very little heat. I did not replace the rad cap but I highly doubt this is causing it to over heat. The clutch fan feels normal, maybe a 1/4 turn trying to spin it by hand.

Put a flushing tee in the heater hose that goes to the intake manifold. Remove the radiator cap and pour antifreeze in the flushing tee while holding it above the top of the radiator until coolant comes out the radiator while the engine is running. Then quickly put the cap on the flushing tee. That burps the heater core and the bypass system...

 

[gw33gp]

When I get a thermostat with no jiggle valve, I drill a small hole (~1/16") in it near the edge as far out as practical and position it at 12:00. I also have the front of the vehicle a little higher when I fill with coolant. I always check it again after driving a while and top off as needed. I have never had a problem using this approach.

I always double check to make sure I install the thermostat the right way. With some vehicles the thermostat can be installed backward and that can momentary cause overheating. I don't remember if Rangers can be installed backward.

 

[franklin2]

I had the same thing happen to me when I changed the waterpump. And I did have one of the heater hoses off when filling, that is standard procedure for me on any engine. But it did not work on this one. I had the exact same issue, overheating with no flow through the thermostat.

I then found the factory procedure for refilling this engine. When refilling they say to take the upper radiator hose off and fill the engine manually that way. Then put the hose on and continue filling like any other engine. It seems strange to me, that is usually where the thermostat is located. But of course it's wide open up there on the 2.8.

I usually leave the radiator cap off or loose till the thermostat opens, to burp any remaining air out of it. This worked and everything straightened out. This is a weird engine with the thermostat down so low in the system.

 

[Saltzman]

Yes, that would be my guess if heat in cab was not working and engine was overheating, both symptoms could be because coolant is too low and not flowing in upper engine

So finally got a break from the cold weather. It was indeed air in system and did exactly what you said and now its running great. Thanks again

 

[RonD]

Good work

Thanks for the update