Gasket sealant

[MikeB]

It's been a while since I did any work requiring gasket sealant. Getting ready to replace a fuel pump and water pump on a Gen I 350.

What do you guys recommend for oil- and coolant-resistant sealants these days? Hi-Temp RTV or something more traditional?

[truckster]

For those applications I like to coat gaskets with Permatex Aviation Form-a-gasket.

[MikeB]

Originally Posted by truckster

For those applications I like to coat gaskets with Permatex Aviation Form-a-gasket.

Now that's old skool!

[Ziegelsteinfaust]

I myself just use black rtv.

[WorldsCrappiestTruck]

I use a thin coat of loctite 518 anaerobic sealer on each mating surface of basically anything I assemble regardless of where. Diff covers, oil pans, water pump gaskets. Put a couple dabs on the surface, smooth with your finger to make an even thin film and send it away.

On gaskets that have a “ridge” molded into the rubber gasket like LS intake, throttle body, etc….i just leave them alone and install dry.

[Willshook]

RTV Black for anything coolant.

Aviation form-a-gasket for anything fuel/oil.

[Orange Crate]

Permatex Gear Oil Gasket Maker 81182. This stuff is really good.

[truckster]

Originally Posted by MikeB

Now that's old skool!

True, but it still works.

[leegreen]

felpro says their gaskets for those locations don't need sealant.
If I thought I'd want to take either of those apart again and reuse gasket I'd aviation form a gasket one side only.
Both sides if I was particularly worried about leaks.
RTV if I was re-using an old gasket or a cheap unknown gasket quality, or had a bad sealing surface.
With sealant on both sides you are unlikely to get the gasket off again in one piece

if I was stocking a roadside toolkit - black RTV

[Joyridin]

I have done this for years and never have a leak. I take 3M Spray trim adhesive and spray the part. Wait a few minutes and put the gasket on the part. Lay it on a flat surface for 15 minutes or so. You might have to add some weight to the part so it is flat. Install on the vehicle. This is for gaskets that are not silicon. They usually do not need anything.

[GSP7]

After using permatex ultra gray last month for a diff cover gasket and the sheet didnt cure after 3 days .... Had to remove the cover and wipe that crap off and bought a regular gasket and installed dry( worked great)

I test any RTV junk first to make sure it drys, to make sure it aint expired and wont dry cure

[MikeB]

Just found some of this stuff in a drawer. I used it 4 years ago to seal a diff cover w/o a gasket. The way it works is you tighten the bolts until the sealant starts to squeeze out. You then wait 1 hour and tighten completely. What you end up with is a compressed, flexible gasket. That diff is still bone dry, not even a hint of a leak.

Not sure if I'll use it for fuel and water pumps, because it's really designed for mating parts with dissimilar metals, like a cast a iron diff and a stamped steel cover. But it's gotta warm up here before I even start the jobs!

Thanks for all the recommendations.

[GSP7]

Originally Posted by MikeB

Just found some of this stuff in a drawer. I used it 4 years ago to seal a diff cover w/o a gasket. The way it works is you tighten the bolts until the sealant starts to squeeze out. You then wait 1 hour and tighten completely. What you end up with is a compressed, flexible gasket. That diff is still bone dry, not even a hint of a leak.

Not sure if I'll use it for fuel and water pumps, because it's really designed for mating parts with dissimilar metals, like a cast a iron diff and a stamped steel cover. But it's gotta warm up here before I even start the jobs!

Thanks for all the recommendations.

Yeah , Ive used it before for diff covers, works great. Didnt know it had a expire date.
Usually left over hardens in the tube from storage so you chuck it. Last stuff was 'bout 2 1/2 years old and I guess it was "expired" and wouldnt cure

Nothing about self life on their data sheet
https://www.permatex.com/wp-content/.../tds/82195.pdf

All I found is 9 month and its trash, or 2 years and its trash

I thing the new stuff isnt as good as the old , because Ive had old gray stuff over 5 year old that sat in my tool box that still cured OK when I used it

[MikeB]

Originally Posted by GSP7

Yeah , Ive used it before for diff covers, works great. Didnt know it had a expire date.
Usually left over hardens in the tube from storage so you chuck it. Last stuff was 'bout 2 1/2 years old and I guess it was "expired" and wouldnt cure

I didn't know the stuff in my post above had an expiration date. I'll check the tube.

Amazingly, it hasn't hardened yet and I was able to squeeze some out after running a drill bit down the nozzle. But if it's expired, I'll chuck it.

[Stocker]

Originally Posted by Orange Crate

Permatex Gear Oil Gasket Maker 81182. This stuff is really good.

That's what I have used on my K20's differential covers and axles. Never had a leak, it is great stuff. Dunno how it is with coolant or fuel, though.