TR2/3/3A Water pump gasket sealant???

Should I use a silicone sealant with the water pump gasket or is the paper gasket enough? Seems I used just the gasket last time and had no leak issues. When I took the old pump off I didn't have to scrape the gasket off either. Same question for the thermostat housing as it is a much thinner paper gasket. Thanks

I wouldn't. Hylomar maybe, not silicone RTV.

Way back when, I used a thin coat of Hylomar on both sides of the paper gasket, and all is well.

One advantage of using a bit of sealant is to hold the gasket in place while fitting the pump, housing or part. Back in the day, we used brush top Permatex or sometimes just a bit of grease.
I don't recall having anything else available but we didn't operate at the leading edge then.
Tom

Permatex is good too, although perhaps overkill in this situation. It seals really well, but pretty much guarantees you'll have to tear the gasket in half to get the joint apart, then it's a PITA to clean up the surfaces for the next time.

My objection to RTV is that it can squeeze out on the inside and form a bead, which can later break off as a string and float around until it clogs something. I've seen this happen even with professionals doing the work.

Many years ago, a friend and I went to Grand Teton National Park, so he could photograph the sunrise. There is a moment when the sun just peeks over the mountains on one side, and lights up the snow caps on the other side, while the valley is still in relative darkness. Very impressive, I recommend it!

When we rolled into the valley, 2 hours before dawn, the dash thermometer read 5F. AND, the heater quit working! Brrr! The old wagon had just gotten it's 100,000 mile tune-up a few weeks before, in preparation for this trip; and the radiator shop later confirmed that it was a string of silicone plugging up the heater. (Not one of GM's better designs, on that engine the water pump had to come off to change the distributor cap.)

Unfortunately, his camera didn't work (apparently got too cold while setting up), but here's an idea of the shot he was going for:

TR3driver said:

Permatex is good too, although perhaps overkill in this situation. It seals really well, but pretty much guarantees you'll have to tear the gasket in half to get the joint apart, then it's a PITA to clean up the surfaces for the next time.

My objection to RTV is that it can squeeze out on the inside and form a bead, which can later break off as a string and float around until it clogs something. I've seen this happen even with professionals doing the work.

Click to expand...

I should have mentioned that we always put the Permatex only on the pat that comes off. That way disassembly is easy and you can scrape off the goo on the bench. Tom