sheriffjim

I'm working on replacing water pump gaskets on my 91 and have a question. I removed the inspection cover on the back of the water pump so I could look at the impeller. Should I use RTV when I replace the gasket on it? I know you're supposed to use RTV on the pump to block gaskets but am not sure if I should do the same for this one. Also is there a particular type of RTV that is best?
Thanks

ajp01

Normally the rubber gasket on the back of the pump seals itself without RTV, via rubber compression. But in your case, since you've removed it and want to reuse it, I would recommend coating the gasket both sides and the metal seating area with Hylomar Blue. It's flexible, seals well, and preserves the gasket over time. Just follow the instructions on the box. Your local shop may carry it also.

sheriffjim

Sorry for the confusion, I am not reusing the old gasket. I should have been more clear. However you have still answered my question. Thank you for the help! I'll get it put together soon, and I'll pressure test it before I put everything else back on the engine.

ajp01

Understood. Since the new gasket might be a different material than came with the pump, it's still a very good idea to use Hylomar on both sides of it to help seal. It may be paper, composition material, rubber, etc, and in all cases the Hylomar will give you a much greater chance of perfect seal. You can also use it on the water pump to block gaskets as well.

Remember to put some sort of sealer on the bolt threads for the pump to engine mounting - they require a sealer too such as Permatex PTFE thread sealer or RTV, your call.

s carter

I don't know about the rest of you but if I have a just pull water pump in hand it's not going back on unless there's reason like a brand new pump and the surfaces weren't cleaned on the block isn't sealing now. (If it's old it's out)
Next I never use an RTV on Gasket Surfaces or on gasket itself, Clean surfaces lite coat of gasket adhesive Spray on pump side let the gasket adhere. As mentioned seal the pump bolt treads but with Teflon thread sealer or an Adequate equal.

colter

Might as well put a new water pump on. When I replaced my pump, I sprayed the two gaskets with some kind of red sealant spray from the parts store to help get the gaskets from leaking. So far 10 years later no leaks.

SouthernSon

Having replaced water pumps a few times on my '96 I never use sealant. Install dry. Be sure to clean the surface really well and use this type gasket that has holes not perfectly round but sort of six sided on two of them. This ensures that the gasket stays in place on the bolts while you maneuver the pump into place. You will appreciate this type gasket.

https://www.summitracing.com/parts/a...ette/year/1996

sheriffjim

I have never seen that kind of gasket before. I'll look into those next time I do something like this.

sheriffjim

I've been away from my car for a few days but in the end I decided to put a thin layer of permatex #2 on the gasket. I may try the gasket sealer spray sometime, but RTV is what I'm familiar with. I understand the reasoning behind replacing the water pump, but the impeller is in perfect shape, and there is no play at all in the shaft. I was initially planning on replacing the pump, but think there is no reason to. I put thread sealant on the bolts, torqued them, and filled the system.
It's holding pressure with no leaks with a pressure tool. I haven't had the chance to get the engine to OT yet but I doubt there will be any issues there.

Thank you all for the advice!

colter

This is what I used on my waterpump gaskets when I did my waterpump a decade ago. I seem to recall I sprayed both sides of the gaskets and had them hanging on a metal coat hanger. And let it sit for several hours before doing the install.

https://www.permatex.com/products/ga...-sealant-6-oz/