Oil line split -> thermostat threads corroded -> HELP!!
 

I am getting a little desperate here:
As you have read, an oil line has split on my Carrera 3.o, the one that attaches to the thermostsat. We have the new line, we took off the lines from the thermostat with the greatest possible care, but the corrosion is just too much on the male threads of the thermostat and the line tightens a while then jumps a thread when we want to secure it. Of course both line fittings do that.
I checked the fittings, and the oil lines bite on 6 treads out of 7 on the thermostat housing.

Now the question: I have seen these thermostat savers our host carries; what is the principle? If it is more threads, I am worrying that there are not enough good treads left on the thermostat housing. If it is slightly undersized threaeds that "bite" on the alloy of the thermostat housing, I am wiling to give it a try.

:( :( :(
Please, anyone must know this?

Hi Noah,
Hmmm, shop in Vermont. Boy, do I wish I was there.
I put it wrong. The std line takes 6 of the 7 threads and still jumps a thread. In my mind a thread saver which by principle takes *more* threads than the original fitting has a slim chance of working, considering there is only 1 thread that is not used by the std fitting.
I guess I'll fork out for a new t-stat then.

George,
Search around for a used or rebuilt T-stat. You're talking a potentially catastrophic failure if the line lets go, though it's more likely to just leak. I looked at the same issue and decided this wasn't an area I wanted to bandaid.

John

1. Chasing the thread works, but it requires a $65 die.
2. The 1" saver does not always seal the leak, but it works well if you take the T-stat out and have some one weld the saver onto the T-stat after you screw it on all the way. Leaks will be sealed
3. I have always found it safer to attach the line to the thermostat first, then attach the line to the other side after.

Depending on the cost difference, I would search out a clean used thermostat, preferably off of the latest (newest) 911 that uses the same one. AFAIK, other than the thread corrosion issue, these parts have an extremely low failure rate. They spend their lives bathed in hot motor oil.

Maybe someone parting out a car on the "For Sale" board here could express mail one to you? Sorry to hear about that trouble, when I replaced my oil lines during my rebuild, I erred on the side of caution and cut off the old fittings w/ a dremel, the fittings were welded on w/ corrosion but the innerds of the therm were beautiful.

For anyone reading this who is replacing these lines in the future, here are my pictures:
http://forums.pelicanparts.com/uploa...1085250791.jpg http://forums.pelicanparts.com/uploa...1085250826.jpg http://forums.pelicanparts.com/uploa...1085250856.jpg

Thanks guys for all the advice.
Thanks to our own Chuck Moreland, there is a new thermostat coming my way as I write this. And thanks to the weak US$, it will be a lot cheaper than the prices quoted here.
I figured I'd rather not do a half-assed repair at the potential cost of my engine, and maybe my car...
I'll experiment with the bad one. I wonder if I can have aluminum welded on and redo the threads (?)

Yes, that can be done. You will have to find a competent welder and machine shop to do it. Time to work the telephone and find that shop.

i bet welding on the tstat would destroy the inside of the tstat. i think there are springs and rubber seals in there. taking the caps off to get to the guts is a challenge all by itself. buy a new one. i sold mine for $75 or so, so the deals are out there.

If one liberally coats these threads with an anti-seize compound the thread failures upon disassembly will be mostly prevented. The threads do not normally make the fluid seal but are a mechanical element that draw the two spherical sealing surfaces together. Jim

It goes without saying that any used thermostat should be *thoroughly* cleaned before being installed. If the engine blew and the thermostat was on the car, be *especially* careful. [Not implying anything about the used being discussed though]

Good luck!

Matt,
How would one clean the t-stat or the oil lines?. thanks. Andy