Perma-cool oil thermostat O-ring

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

Moderator: drseti

User avatar
dstclair
Posts: 948
Joined: Thu Mar 06, 2008 11:23 am
Location: Allen, TX

Perma-cool oil thermostat O-ring

Postby dstclair » Mon Dec 04, 2017 10:33 am

I have a Perma-Cool Oil Thermostat (http://www.shop.perma-cool.com/media/300013%20rev6.pdf) that appears to be seeping a tiny bit of oil. The oil accumulates on the 'end cap'. My mechanic and I suspect that there is an o-ring behind the end cap that needs to be replaced. Before making a big mess and removing the end cap, does anyone know if there is indeed a field replaceable o-ring?

I have dropped a note to Perma-Cool as well.

It would be a bit of a PITA to replace the oil thermostat, although the part is only $80.
dave

3Dreaming
Posts: 1991
Joined: Sun Jan 10, 2010 6:13 pm
Location: noble, IL USA

Re: Perma-cool oil thermostat O-ring

Postby 3Dreaming » Mon Dec 04, 2017 8:57 pm

I don't know the answer, but I have aused one on the shelf. If I remember I'll check tomorrow.

TimTaylor
Posts: 320
Joined: Tue Feb 21, 2017 7:17 pm
Contact:

Re: Perma-cool oil thermostat O-ring

Postby TimTaylor » Mon Dec 04, 2017 9:54 pm

3Dreaming wrote:I don't know the answer, but I have aused one on the shelf. If I remember I'll check tomorrow.

Why don't you write yourself a note so you WILL remember? Simple enough.
Commercial Pilot Airplane Single & Multiengine Land; Instrument Airplane;
Sport Endorsement Airplane Single Engine Sea;
Flight Instructor Airplane Single And Multiengine;
Ground Instructor Advanced Instrument

3Dreaming
Posts: 1991
Joined: Sun Jan 10, 2010 6:13 pm
Location: noble, IL USA

Re: Perma-cool oil thermostat O-ring

Postby 3Dreaming » Tue Dec 05, 2017 9:48 am

TimTaylor wrote:
3Dreaming wrote:I don't know the answer, but I have aused one on the shelf. If I remember I'll check tomorrow.

Why don't you write yourself a note so you WILL remember? Simple enough.


Because I would likely forget to bring it to work with me. :oops:

User avatar
dstclair
Posts: 948
Joined: Thu Mar 06, 2008 11:23 am
Location: Allen, TX

Re: Perma-cool oil thermostat O-ring

Postby dstclair » Tue Dec 05, 2017 9:55 am

If you happen to remember, could you let me know the size?
dave

3Dreaming
Posts: 1991
Joined: Sun Jan 10, 2010 6:13 pm
Location: noble, IL USA

Re: Perma-cool oil thermostat O-ring

Postby 3Dreaming » Tue Dec 05, 2017 11:34 am

OK, I popped the end cap off, removed the o rings and measured. There are 2 o rings. Laying on a ruler the OD is 34mm, and the ID is 30mm. I recently completed a hose change on a 912 and had the spare parts still here to show the customer. The intake to cylinder o ring for the 912 is 34x2. The thermostat o ring just fits inside of the intake o ring. The intake o ring fits the groove in the thermostat cap just fine. Based on that I would say that it is a 30x2 metric o ring.

3Dreaming
Posts: 1991
Joined: Sun Jan 10, 2010 6:13 pm
Location: noble, IL USA

Re: Perma-cool oil thermostat O-ring

Postby 3Dreaming » Thu Dec 07, 2017 10:47 am

Also my thermostat came apart easy, just a little twist on the cap and it popped right out. Don't lose the washer. You might need a clamp or something to push it back together to reinstall the snap ring after replacing the O-rings.

User avatar
dstclair
Posts: 948
Joined: Thu Mar 06, 2008 11:23 am
Location: Allen, TX

Re: Perma-cool oil thermostat O-ring

Postby dstclair » Thu Dec 07, 2017 9:24 pm

I received the below from Perma-Cool:
There are two. Though they can be replaced, those t-stats are pressure tested here after assembly to insure that they do not leak. The O-rings are a little tricky when replacing the caps also as they are a tight fit and can get damaged during the assembly process (or in your case, attempting to re-assemble.) We can only tell this ourselves after the pressure test.

You might be better off ordering a new one in terms of time saved and avoiding frustration if it leaks after you have gone to the trouble of trying to repair.

Do you believe the O-rings can be replaced easily based on your disassembly?
dave

3Dreaming
Posts: 1991
Joined: Sun Jan 10, 2010 6:13 pm
Location: noble, IL USA

Re: Perma-cool oil thermostat O-ring

Postby 3Dreaming » Thu Dec 07, 2017 10:16 pm

dstclair wrote:I received the below from Perma-Cool:
There are two. Though they can be replaced, those t-stats are pressure tested here after assembly to insure that they do not leak. The O-rings are a little tricky when replacing the caps also as they are a tight fit and can get damaged during the assembly process (or in your case, attempting to re-assemble.) We can only tell this ourselves after the pressure test.

You might be better off ordering a new one in terms of time saved and avoiding frustration if it leaks after you have gone to the trouble of trying to repair.

Do you believe the O-rings can be replaced easily based on your disassembly?


I put the one I disassembled back together with the old o-rings, and it went together easy. Even with new o-rings I don't think it will be a problem, just lube the o-rings before putting it back together.


Return to “Ask The Mechanic”

Who is online

Users browsing this forum: No registered users and 1 guest