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Engine block coolant plug - use teflon or gasket?

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https://sigforum.com/eve/forums/a/tpc/f/320601935/m/6630032715

September 13, 2025, 10:04 PM
Russ59
Engine block coolant plug - use teflon or gasket?
I’m helping a friend with a recently purchased 1986 Porsche. We flushed the coolant, including removing the engine plug to help drain.

Anywho, after running it a few miles, there may be a leak from that plug (I haven’t been able to crawl under it).

Porsche doesn’t call for a washer. Could Teflon be used? Or some paste like sealant on the threads? Obviously needs to handle temps and coolant.


P229
September 13, 2025, 10:54 PM
hrcjon
what kind of threads on what kind of plug? Tapered? Does it have a head as you suggest with the idea of a washer. more details would enable a good answer. Both teflon and pipe threading compound would have no issues with coolang temps and material, but let's discuss what's the right answer... What model and what engine would help as well...


“So in war, the way is to avoid what is strong, and strike at what is weak.”
September 13, 2025, 11:05 PM
pbslinger
German car companies don't usually leave you wondering what product or seal to put on anything that uses or needs one if you know where to look. I have good luck with more general thread sealing with Gasoila pipe dopes.
September 14, 2025, 01:18 AM
Speedbird
quote:
Originally posted by pbslinger:
German car companies don't usually leave you wondering what product or seal to put on anything that uses or needs one if you know where to look. I have good luck with more general thread sealing with Gasoila pipe dopes.

Agreed ^.

My Toyota uses lots of semi crush gasket/washers that seem to be able to be used more than once, but I usually replace. Maybe your P-car calls for one that was missed the last time?

Permatex makes this stuff that is a combination sealer and blue. I will be using for the manual trans in my Ford.
September 14, 2025, 05:25 AM
smlsig
Can you provide us with the year and model including engine size?

https://rennlist.com/

And

https://www.pelicanparts.com/t...tech_center_main.htm

Are good sources for all things Porsche


------------------
Eddie

Our Founding Fathers were men who understood that the right thing is not necessarily the written thing. -kkina
September 14, 2025, 11:50 AM
4MUL8R
Interactions of sealants and coolants that are not approved by the OEM can occur. Why risk it?


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Trying to simplify my life...
September 14, 2025, 12:53 PM
Russ59
944 2.5L.

I don’t believe the bolt is tapered.

I’m on the road right now and not in front of my computer. Doing my research on my phone.

I’ve used Rennline and Pelican and didn’t find anything definitive.

When I removed the bolt originally, I recall seeing some type of junk on the threads. I assumed it was a type of old sealant.

Thanks for replies and I’ll keep looking. Teflon would be the easiest fix, using it sparingly.


P229
September 14, 2025, 10:06 PM
aileron
Loctite 567 - easily sourced, and seals EVERY SINGLE TIME. 577 works great too. Happy on all metals including aluminum and magnesium alloys