External Thermostat Leak

[montauk]

I couldn't get any of my large crescent wrenches to fit in there and have an room to turn them. I thought the crow foot wrenches might make it a bit easier. Besides, I don't need much of a reason to buy more tools.

[fintstone]

Originally Posted by Nditiz1

I think everyone was thinking it was going to be the ones on the bottom. Oh well at least you found it. Now, you may have to take off the front line in order to tighten the rear.

Nah. The one's on the bottom probably have not been loosened since new. No reason to do so. It was always going to be the something most recently worked on. The new lines were the most likely.

[montauk]

So I took a few minutes at lunch and tried to tighten the horizontal nut closest to the fender. No joy. It wouldn't budge so I loosened it to see if anything looked odd. Everything looked fine so why the leak. Then I noticed that there a lot of sludge on the threads. I'm wondering if the mechanic that put the lines on simply stopped tightening when the nut stopped due to the threads being clogged thinking his work was done.

I'll have more time this weekend to dive into it.

I am worried that the real problem is that the tubing is cracked. I hope not!!!!

[fintstone]

Originally Posted by montauk

So I took a few minutes at lunch and tried to tighten the horizontal nut closest to the fender. No joy. It wouldn't budge so I loosened it to see if anything looked odd. Everything looked fine so why the leak. Then I noticed that there a lot of sludge on the threads. I'm wondering if the mechanic that put the lines on simply stopped tightening when the nut stopped due to the threads being clogged thinking his work was done.

I'll have more time this weekend to dive into it.

I am worried that the real problem is that the tubing is cracked. I hope not!!!!

You can use oil plug sealant on the threads, but that will not help if the nuts are not tight enough due to the threads being boogered up (and it is coming out from the back of the nut)

Also, check for a crack in the thermostat. I circled a spot (in red) I would check in the photo. Also, the hoses must sit perfectly straight in the thermostat housing to seal. In this photo (see blue arrows), it looks canted a bit (might just be the photo angle).

[917_Langheck]

The first thing I would do is clean clean clean the entire work area within the car.




A clean work area greatly reduces the chance of incorporation of dirt into those sensitive, and expensive thermostat housing threads.

Remove the hard lines from the top of the housing and clean clean clean the threads on both sides.

If you have noticed crud in there already, it needs to be cleaned out.

Then, don't go back to the shop that fitted those hardlines ever again.

[montauk]

Originally Posted by fintstone

You can use oil plug sealant on the threads, but that will not help if the nuts are not tight enough due to the threads being boogered up (and it is coming out from the back of the nut)

Also, check for a crack in the thermostat. I circled a spot (in red) I would check in the photo. Also, the hoses must sit perfectly straight in the thermostat housing to seal. In this photo (see blue arrows), it looks canted a bit (might just be the photo angle).

Looking at the photo, just to the left of your red circle, the thread looks buggered up.

I'm planning to loosen up all the connections so I can get all the fittings seated correctly.
Dave

[GH85Carrera]

Originally Posted by manbridge 74

Glen, what brand were your short hoses? Just replaced mine but haven’t started it yet… I did not “reef” them super tight.

Wow, good question. I did mine back in March of 2009, and 60,000 miles ago. I would guess and I suspect I used Porsche branded hoses, but I can't prove it.

Mine just took a bit more of a squeeze. Get the two wrenches aligned where the handles are just offset, and squeeze them together.


Before. The old lines were seeping, and almost certainly the original lines from 1985.



After, much better. The are not pretty anymore and many many road trips in the rain. Adding the fan was a great project. That fan really helps in hot conditions. Even at highway speeds, the fan will cool down the engine 10 to 15 degrees. If I turn it off, the temp goes up, and back down when the fan runs.

My cooler does not have the bung for the temperature switch as it is stock from 1985. I just wired in an on off toggle switch and relay.

[montauk]

So if I do need a new T-stat housing, should I get the stock one
https://www.pelicanparts.com/More_Info/93010701701.htm?pn=930-107-017-01-OEM

Or should I get the aftermarket with bolt heads instead of slots
https://www.pelicanparts.com/More_Info/93010701700.htm?pn=930-107-017-00-INT

Should I buy a new thermostat while I'm at it? I imagine that's probably wise. I don't think the new housings ship with thermostats installed.
Thanks
Dave

[fintstone]

If it is the threads that you are thinking are boogered up that are causing your problem, I would take a fine file or pick and clean them up enough/fix them enough to tighten it down more. Those back threads will prevent you from screwing it on far enough if bad (raised), but their absence probably will not. The harder metal in the line will help clean up the threads some once you clean them up. I would try very hard to save that thermostat housing...both for cost and because you may bugger up your front lines removing it. They may have never been off. Those are the ones that usually cause folks problems.

[montauk]

Originally Posted by fintstone

If it is the threads that you are thinking are boogered up that are causing your problem, I would take a fine file or pick and clean them up enough/fix them enough to tighten it down more. Those back threads will prevent you from screwing it on far enough if bad (raised), but their absence probably will not. The harder metal in the line will help clean up the threads some once you clean them up. I would try very hard to save that thermostat housing...both for cost and because you may bugger up your front lines removing it. They may have never been off. Those are the ones that usually cause folks problems.

Good idea. I try that next.

[pampadori]

Remember this - The seal is made at the flare, not the threads.
The threads just provide a mechanical means to crush the male flare into the female flare. Check for cracks, pits, and roundness on both the male and female sides. If that looks good, tighten the nuts. If they still leak, go tighter.

[montauk]

I found a thread chaser at McMaster Carr, $75.
https://www.mcmaster.com/dies/thread-size~m30/

I also found a cheapo die on Ebay.
https://www.ebay.com/itm/391757154295?chn=ps&_trkparms=ispr%3D1&amdata=enc%3A1OSFtFDN_Q6atxZav6z8YTg17&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=391757154295&targetid=4580702891777581&device=c&mktype=&googleloc=&poi=&campaignid=418640321&mkgroupid=1233652283797640&rlsatarget=pla-4580702891777581&abcId=9300602&merchantid=51291&msclkid=b61092d9114e12251877f1f3eb9f5053

Both are large enough that I'm not sure they'll even fit between the fittings.

I'll see what I can do with a jewelers file. If I have to replace the thermostat, I think I'll drop the whole mess on the floor from the trombone back.

[montauk]

Originally Posted by pampadori

Remember this - The seal is made at the flare, not the threads.
The threads just provide a mechanical means to crush the male flare into the female flare. Check for cracks, pits, and roundness on both the male and female sides. If that looks good, tighten the nuts. If they still leak, go tighter.

Thanks, I'm aware of that. The problem is I can't go tighter with the threads as they are.

[montauk]

It’s fixed. I ran the die I bought on EBay down both rear tubes on the T stat housing. One of the tubes was in really rough shape.

To turn the die, I stuck the forks from a crows foot wrench in the notches in the die and used a socket extension for a handle.

[Nditiz1]

Nice work! Thanks for the closure.

[montauk]

BTW, I wanted to mention something about the tubes going to the front trombone. My first post about this problem shows what looks like too many thread showing on one of the fittings. Tony also pointed out that the nut looked too thin. If you look at the last set of photos you can see that the nut is in fact normal size with no extra threads showing.

I don't know how it happened but that first set of photos made the cylindrical part of the nut look like threads. Weird.

Dave

[pfbz]

Bumping this old thread... I have some external thermostat oil leaks and this thread was the best one I found for isolating and resolving leaks in that area.

After some basic cleaning and inspection, i'm guessing it is the same issue that @montauk had... A shop replaced the upper oil line and didn't bother to properly clean and chase the threads so it isn't making a good seal.

Picture of mine, prior to cleaning...

[pfbz]

A bit easier fix, but the same shop previously replaced the oil level sensor (again, under previous ownership, but documented) and didn't torque it properly... One bolt was completely loose and the others weren't even fully hand tight. Not sure what the torque spec on this is but you could visibly see the gasket compressing and squeezing out excess oil as I tightened the bolts down a bit. So much crud on it originally you couldn't even see the bolts!