Teflon tape?

[steno]

Hi all!
After a couple attempts, I still have a leaking water pump bolt on my '93 302. Think a wrap of teflon tape could fix it? It's temperature rated to over 400degrees.
Thanks, Sten

[Gumball]

I like to use a couple of GM coolant system tablets to combat those sort of things. Just crush them up and drop in the filler.

Some will say that using those is a crutch, but I've had quite a few engine builders recommend it and have never had leak issues.

[DaleG]

Use hi-temp RTV as a thread sealant?

[BEAR-AvHistory]

+1 on Dales recommendation. Permatex makes a good one.

[NAZ]

Teflon tape will do nothing for you and causes so many problems I don't consider there to be any automotive use of this product. For tapered pipe threads there is nothing that works as good as Loctite PST in either stick form or in a tube and there are no bad side effects from this product like the stringy teflon tape. Been using PST since the 80's and it never fails on pipe threads even on high pressure hot hydraulic fittings. Never tried it on straight coarse threads like your application requires but in theory it may work as it fills gaps and turns to a plastic like barrier blocking leaks through threads. I've always had good luck using a generous amount of Permatex Ultra Black RTV after cleaning everything good including the threaded holes. However, some folks have had good luck specifically on water pump fasteners with some of the Loctite products specifically designed for sealing threads. There are a bunch of them so go on heir website and pick one. Loctite 545 hydraulic / pneumatic thread sealant may work as I know others that swear by it for this particular application. I'll keep using the Ultra Black as long as it works for me. Good luck and when you find the perfect sealant share with the rest of us.

[mikeinatlanta]

Teflon tape is for sealing pipe threads, nothing more.

[Melb-Mike]

You may want to try Loctite Aviation Gasket sealer. It works excellent on bolt threads going into water jackets or into oil. It's available at NAPA auto parts stores, maybe others as well. Another great product is Mercrury Perfect-Seal used on their outboards and stern drives for any bolt going thru a water jacket or oil cavity.

Also as NAZ recommended, Loctite PST is excellent at sealing threads but better suited for pipe threads. It tends to set up so hard that removal afterwards could be a challenge. Water pump bolts, head bolts and other similar type fasteners are likely to need to be serviceable. By the way, stainless steel pipe threads are difficult to seal and PST solves that problem very well.

[CraigS]

Use hi-temp RTV as a thread sealant?

I agree. I also like Ultra-Grey as it has slightly thicker consistency.

[Mustang Man]

Permatex non-hardening #2 is perfect for that. I use it on the lower row of head bolts/studs in late-model small-block builds and on the water pump bolt threads, etc. Anything going into the coolant jacket. NEVER use thread tape on any engine fasteners. I don't like using silicone on bolts either, because it can make them tough to remove and leaves silicone bits in the threads of the hole. I DO like PST, mentioned above, but only for pipe fittings like coolant sensors and the like going into the intake or block.

HTH...
Mark

[benkibler]

I use ARP thread sealer for all my water, fuel, and air fittings. 9 years later, still no leaks. Tape is horrible: bits of it end up inside the pipe or fitting, and if you're past the filter, it's going into your engine.

64678

[RoadRacer]

I use ARP thread sealer for all my water, fuel, and air fittings

+1 I try to use only ARP products on cars

[Bob Cowan]

Are you sure it's the threads? If you've tried a couple of times to fix it (and did the fix right), maybe it's a surrounding gasket instead of bolt threads.

[steno]

Ok... I got the message! I took the pump off, chased all the holes, re-assembled everything with #2 permatex, waited 2 days to cure and filled it up. Had one tiny leak which went way after a heat cycle. It has not returned!!
I guess this one time NOT to think out of the box!
Thanks, Sten