Coolant leak past Radiator Cap

[Big Papa Gecko]

SEE, it doesn't pay to be a cheap-O, ha ha. That's why I try to buy OEM if it makes sense.

Fords just have that fickle nature to them, diesels will throw a fit if its not a Motorcraft oil filter, and apparently raptors hate aftermarket radiator caps.

 

[1BAD454SSv2]

I Run A Subaru Cap 18.5 psi along with Subaru blue coolant .

 

[CoronaRaptor]

I Run A Subaru Cap 18.5 psi along with Subaru blue coolant .

View attachment 322059

Well, isn't that pretty! (no sarcasm), the engine compartment needs a detail, you live in Arizona and only drive to Starbucks, c'mon (sarcasm).

 

[Big Papa Gecko]

I Run A Subaru Cap 18.5 psi along with Subaru blue coolant .

View attachment 322059

No issues running at a higher pressure?

 

[1BAD454SSv2]

No issues it bumps boiling point up a tad but the silicone gasket material is really good . I installed when i put new Ron Davis radiator in few years ago. He pressure tests his radiators to 40 PSI . My 2019 Raptor comes with 20 PSI cap.

 

[1BAD454SSv2]

Well, isn't that pretty! (no sarcasm), the engine compartment needs a detail, you live in Arizona and only drive to Starbucks, c'mon (sarcasm).

Starbucks only when i'm in the GEN2 .

 

[Skiracer3]

I've just about had it with my 2014 6.2. It's had a very slight leak around the thermostat housing for that last year. I've tried everything from the good Ford round O-ring (leaked) the good FelPro O-ring (still leaked) I looked forever and finally found the square gasket the thermostat fits into. AND it still leaks. I even changed the water outlet housing. My next move is to drop the pressure on the radiator cap. I'm thinking if I drop the press a little, the leak may not come back. anyone have any other ideas? 1BAD454SSv2, what year and model Subaru cap fit your truck?

 

[Skiracer3]

I'm beginning to think Ford circled their problem and filled it in with blue!

 

[CoronaRaptor]

@1BAD454SSv2 ^^^^^

 

[MTF]

I've just about had it with my 2014 6.2. It's had a very slight leak around the thermostat housing for that last year. I've tried everything from the good Ford round O-ring (leaked) the good FelPro O-ring (still leaked) I looked forever and finally found the square gasket the thermostat fits into. AND it still leaks. I even changed the water outlet housing. My next move is to drop the pressure on the radiator cap. I'm thinking if I drop the press a little, the leak may not come back. anyone have any other ideas? 1BAD454SSv2, what year and model Subaru cap fit your truck?

Are you sure you are using the right thermostat?
Are you sure you didn't over tighten the new one, was it a OEM housing?
If the thermostat is too thin around the edge or the diameter is a hair too small it won't fill it up properly.

When I change my thermostats, it is really "REALLY" hard to get back in and down, lots of antifreeze around it to lube it up.
I have to use a rounded out small chisel to get it started and work my way around the thermostat, that's how difficult it is.
And I bought aftermarket Hi- Performance Hi-Flow, full 1 inch opening on Amazon, they are the MotoRad brand.



I would use a thin washer under the bolt heads it could be you are bottoming out before it's tight.
Have you chased the bolts down without the housing?
Just guessing here.

Maybe try using a sealant, can't hurt.
https://www.amazon.com/dp/B000HBGI8K/?tag=fordraptorforum-20
Just make sure that everything is oil free and dry before applying.