There are a couple fittings that thread into the block of the motor that have coolant flowing through them.

I noticed when I removed them from the motor that there is some type of sealant on the threads. The same stuff looks like it is used on the nipple that threads into the diaphram fuel pump on the side of the motor.

It does not look like thread locking stuff, plus that stuff does not seal.

Anybody know what this is?

Thanks,
Russ

 

It is probably liquid pipe sealant that has been heated. Theres a few different kinds of pipe dope. I like loctite's.

 

I went out to the truck to see what kind we use, its been rolling around to the point barely can make it out. I think it's permatex teflon sealant. I use it on my 18 wheelers to seal water connections ect.. I've never had a leak using it. When you apply it just be a couple of threads from the end so it doesn't get into the cooling system. Good luck.