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Re: Coolant Bleeder screw leak

Posted: Tue Sep 30, 2025 7:14 pm
by blueline
PSU_Crash wrote: Tue Sep 30, 2025 6:24 pm
Zirconocene wrote: Tue Sep 30, 2025 10:10 am I'm sure that @dr bob 's method will work. The other thing you can try is bonded rubber washers. I've been using them for other applications (engine and transmission oil) and they've been great.

Good luck
I forgot about those! I've used them with great success in the past (and future). I have a pack of random sizes in the shop. May swap out my crush washer soon
I had no idea how many different types and kinds of bonded washers there were. (Not surprising given my anemic wrenching background and [lack of] those kinds of skills...)

https://www.mcmaster.com/products/bonde ... g-washers/

McMaster-Carr must be the king and quality leader of, well, just about everything. Their catalogue never ceases to amaze.

Re: Coolant Bleeder screw leak

Posted: Tue Sep 30, 2025 8:21 pm
by dr bob
Poorsche44 wrote: Tue Sep 30, 2025 4:28 am Is there any specific brand or type I should look out for? I.e. hardening vs non hardening? Also does the paste hinder the venting ability of the screw?
Local lowes has exactly the jar I have:\. Non-hardening, non-separating, etc.

https://www.lowes.com/pd/Oatey-Great-Wh ... nt/4750813

1oz Tube of permatex version, in a small tube. The tube is a lot less messy to use and store.

https://www.amazon.com/Permatex-80632-T ... KEBT0?th=1

Re: Coolant Bleeder screw leak

Posted: Fri Oct 10, 2025 12:12 pm
by BennSport
Just picked up the sealant and planing on fixing it today. Just to clarify, I should apply some on the threads and both sides of the washer?

Re: Coolant Bleeder screw leak

Posted: Fri Oct 10, 2025 7:18 pm
by CEW
I’m not Dr. Bob but I can answer this one…yes, small uniform amount on threads and both sides of washer.

Re: Coolant Bleeder screw leak

Posted: Fri Oct 10, 2025 8:03 pm
by PSU_Crash
CEW wrote: Fri Oct 10, 2025 7:18 pm I’m not Dr. Bob but I can answer this one…yes, small uniform amount on threads and both sides of washer.
100% (I am also not the Dr.)

Re: Coolant Bleeder screw leak

Posted: Sat Oct 11, 2025 8:10 am
by Tom
Call me a contrarian, but I'm not a fan of putting sealant on the bleeder bolt. Leaking from that bolt is not a common problem at all, so 'something' must be up with your neck, bolt, or seal. Putting sealant on it might be an effective stop gap, but what about all the sleepless nights wondering what's really wrong and how the Porsche gods are going to get back at you? Joking aside, it is a bleeder, so sealant kind of undermines its purpose in life. Maybe seal it for now but keep your eyes open for replacement parts...

Re: Coolant Bleeder screw leak

Posted: Sat Oct 11, 2025 10:18 am
by BennSport
I ended up sealing it yesterday with the new bleeder screw, washer and ptfe paste and it seems to be holding up. I was worried about using sealant on a bleed screw as well Tom, but it didn’t impede the venting process at all fortunately. It also looked like someone used a keensert/helicoil on the coolant neck is so I’m sure that’s part of the problem as well. If the issue every arises again I’ll just buy a new neck and start over from there.

Re: Coolant Bleeder screw leak

Posted: Sat Oct 11, 2025 10:28 am
by Tom
Poorsche44 wrote: Sat Oct 11, 2025 10:18 am I ended up sealing it yesterday with the new bleeder screw, washer and ptfe paste and it seems to be holding up. I was worried about using sealant on a bleed screw as well Tom, but it didn’t impede the venting process at all fortunately. It also looked like someone used a keensert/helicoil on the coolant neck is so I’m sure that’s part of the problem as well. If the issue every arises again I’ll just buy a new neck and start over from there.
Ah, that's probably the issue. I'm a big fan of helicoils generally, but I could see it causing leaks in the coolant neck.

Re: Coolant Bleeder screw leak

Posted: Sat Oct 11, 2025 2:15 pm
by BennSport
Yea, I’m just assuming the washer has less surface area to seal since the threads had to be bored out further than OEM to fit the insert

Re: Coolant Bleeder screw leak

Posted: Sat Oct 18, 2025 8:40 am
by 951tom
Went thru the same headaches and temp fixes on my car. Ended up buying all new coolant neck, bolts, gaskets, bleeder bolt, and washer. The sealing surface on the neck had become distorted. I recall the whole thing costing around $100+ but the Turbos have an extra spacer.

Tom
'87 951