Do I Need Any Sealant Here?

[Fitz98]

98 Expedition 5.4 4x4
I have this part

That presses into this hole through the block behind the water pump

That will look like this, only new when installed. It feeds the tube that goes to the heater core.

Is this just pressed in dry, or is there some sealant needed? What creates a watertight seal behind the pump where this goes through the block?
My old one leaked at the tube that goes from this part to the heater hose which caused coolant to leak on top of the block under the intake.
Here is a link to the thread with some more pictures and amazing diagnostics and parts support from bdcardinal
https://www.bobistheoilguy.com/foru...edition-need-help-to-find-it#Post5118422

 

[E150GT]

Im no expert but it looks like it has o-ring seals on it. Maybe lube it with a little coolant before pressing it in like the 3800 series coolant elbows.

 

[Fitz98]

Originally Posted by E150GT
Im no expert but it looks like it has o-ring seals on it. Maybe lube it with a little coolant before pressing it in like the 3800 series coolant elbows.

The O-rings seal a separate tube that goes under the intake to the heater core hose. There are no seals where the part presses into the block through the water pump side. Just machined surfaces.

 

[Chris142]

A little bit of oil on the seals is all.

 

[Dave9]

Generally you pull the old one off and see what's there, gasket or RTV, but it is strange to me that this looks like a part that would leak without a seal there, yet does not use fasteners to attach (or does it and that is not apparent?).

Without more info, I'd use RTV sealant, and put a light coat of silicone grease on the o-rings.

 

[Fitz98]

Just came back from dealer picking up some parts. I asked their service department what they do. They said either some Indian gasket shellac or Locktite. They threw in a bottle of Locktite 243. They said it was more to prevent part from moving or backing out than sealing.

 

[nthach]

If it's plastic, no Loctite. It might attack the material. I'll wait for bdcardinal to chime in here.

 

[bdcardinal]

Originally Posted by nthach
If it's plastic, no Loctite. It might attack the material. I'll wait for bdcardinal to chime in here.


Just grabbed one off the shelf and it is metal, well if it was plastic it would be really heavy for plastic. I seem to remember slamming these in dry, they don't go anywhere especially on an iron block.

 

[Fitz98]

Thanks guys, it is metal, I put a magnet to mine.
I had to beat on the old one with a hammer to get it out, but I was more concerned about fluid leakage around that dry fit on the reinstall.
I guess locktite or indian head gasket couldn't hurt right?

 

[bdcardinal]

Not sure if I would use 243 on that, they have specific versions for press fit, we use them on the 7.3L injector cups.

 

[The_Eric]

I'm a big fan of using silicone grease on cooling system o-rings. Some dish soap works in a pinch too. Ideally you wouldn't use petroleum based lubes as they can attack the o-ring

 

[mattd]

Use a little white grease and you should be fine.

 

[clinebarger]

I would use a Non-Setting Joint Compound......Hylomar Blue or Permatex Aviation Form-a-Gasket.

 

[Trav]

+1 Hylomar M is perfect for this job.

 

[Fitz98]

Originally Posted by Trav
+1 Hylomar M is perfect for this job.

Thanks Trav!
Looks like a perfect solution.