Need help with Thermostat leaking

[black roadster]

Had to replace the thermostat on my wife's Mustang.

Drained the coolant.
Removed water neck.
Cleaned gasket material off block and water neck.
Placed on new paper gasket and thermostat.
Filled with coolant.

Now it leaks.

Tightened bolts more. Still leaks.

Removed everything again.

Gasket is a self adhesive kind so it's ruined.
Scraped off new gasket.
Used RTV Silicone to make a new gasket.
Reassembled.

Still leaks!

Any ideas?

I hate Fords!

[sammm]

More RTV.

[POS Racing]

Or a thicker gasket!

[Dave04]

Liberal use of a mig welder?

[channelmaniac]

Hmmm...

Back in my Ford days (Ford Fiesta - the one from the late 70s/early 80s that was made by VW)... we used to take a cereal or cracker box, trace and cut out a gasket and coat it with that black gooey gasket compound... never RTV... Always sealed and never leaked... and didn't need the curing time the RTV needed.

Sounds like the mating surfaces are boogered, not quite clean, or you aren't letting the RTV cure enough.

RJ

[Radio-Active]

Hmmm...

Back in my Ford days (Ford Fiesta - the one from the late 70s/early 80s that was made by VW)... we used to take a cereal or cracker box, trace and cut out a gasket and coat it with that black gooey gasket compound... never RTV... Always sealed and never leaked... and didn't need the curing time the RTV needed.

Sounds like the mating surfaces are boogered, not quite clean, or you aren't letting the RTV cure enough.

RJ

Black Gooey stuff called Permatex Form-a-Gasket #2. Get the aviation type as it comes in a jar with an aplicator brush. Otherwise the other comes in a tube and is thicker and makes your fingers messy. Works good, but is very hard to get off the next time.

The hose, If you took it off or bended it backwards, make be leaking and seeping out one of the re-enforced treads. I have seen that happen on my older cars a couple of times.

[black roadster]

Well to add insult to injury I also broke the cheapo plastic petcock valve on the radiator drain. I hope the autoparts store has a replacement.

This easy job has turned into a nightmare!

I probably didn't let the CTV dry enough. Will try round two tomorrow.

[channelmaniac]

Uh-oh....

Good luck with that... Billy Blaze went through that recently and had to get a new radiator.

RJ

[black roadster]

Day two is better.

I bought a new paper gasket and applied it. I then applied sealant. I got something similar to the Permatex stuff. It's a non-hardening brush on much like the Permatex and even says Type 3 Aviation on it but it's called VersaChem Prime Seal Gasket Sealant. I forgot what was recommended and this was the only brush on gasket stuff O'Reillys had. Says it's resistant to water and antifreeze and works on metal to metal or soft and hard gaskets.

Per the instructions, I applied to both surfaces, and let it air dry for a few minutes. I then reassembled it. I'm going to let it set for a few hours before adding coolant.

I got lucky on the radiator drain plug too. A carefully manipulated screwdriver removed the threads of the old plug and O'Reillys had a replacement for a few bucks.

Here's hoping that gooey sealant holds.

[black roadster]

No leaks!

Heater took a while to kick in though. I will monitor this. System was run until warm to let the air bubbles out.

[channelmaniac]

Sweet!