how to render a perfectly good thermostat useless
 

I was removing the oil lines from the thermostat and 3 of the 4 came out without stripping the threads. They'd been soaking for a week in PB Blaster. The 4th wouldn't budge so I put the thermostat in a vice and went at it one more time when I heard a loud crack as I flew backwards. Looks like I'll need a new thermostat and engine to thermostat oil line.

http://img87.imageshack.us/img87/2540/img0120vl0.jpg

Crap! I hate it when that happens!
No injuries? (other than the broken stat)

That's the kind of stuff I fear!!!

Was any heat processes used?

Best,

No injuries but at one point I was pulling so hard I thought my previously broken collar bone was going to break again.
The first 3 were pretty tough but they all came off leaving the thermostat threads intact. The "block" that you use your second wrench on for this line is smaller than the one for the others and the wrench was slipping so that's why I put it in the vice. No heat was used, probably should have but I can't say I ever imagined the housing would just rip apart like that. Oh well. Anyone got a thermostat laying around? And an engine to thermostat oil line?

I did the same thing while replacing some lines.....not terribly expensive to buy a new one, but aggravating. After I completely cleaned and degreased the broken thermostat, I progressively cut it on my buffing wheel with finer and finer polish and rouge until it looked like it had been chromed. Then I found a wooden trophy-type base, stained and varnished the base and then mounted the beautiful polished thermostat. I put more effort into this project than the oil lines that I was replacing.

Steve

:) I broke my AC condensor mounting bracket in a similar fashion. Sucks...

Ouch. With a Dremmel tool, you might still be able to salvage the line, but it also might just be best to start with new stuff...

-Wayne

Pics?

Nice break! http://forums.pelicanparts.com/support/smileys/wat6.gif

Your story of the thermostat in the vice reminded me of destroying mine in a similar way, while trying to get one of the long hard lines loose. I had tried lots of heat and PB-Blaster, with no luck. So I wrestled the whole mess out of the car, put the t-stat in the bench vise with the line sticking 6 feet out into the garage, and used the hard line (which I was going to replace anyway) as the lever arm to break the joint loose. What happened was that the line came off and took all of the aluminum threads with it. I had no confidence that the "thermostat thread saver" attachments would work on what was left, so I junked the thermostat.

I was picturing what would happen if the vice broke off the bench and came flying back at me. Nothing like applying a lot of force and then slowly beginning to realize that it's probably a bad idea.

Good luck
Scott

I consider $400 fairly expensive ... but at least it's available for purchase.
:)

The best way to tackle these thermostats seems to be with sharp blows on the wrench. Heat doesn't seem to be a good idea with these. Here's why I think that:

The collar nut on the oil line is steel, the t-stat is alloy. The alloy likely has a higher rate of thermal expansion. So I believe heat is actually expanding the alloy more than the steel and making the connection tighter. The key would be to apply heat sparingly so it only heats the nut. But alloy is a good heat sink so isolating heat to the nut only is not likely.

The internals of the t-stat have wax components. Heat it too much and you'll compromise the operation of the t-stat- it may be stuck closed or open (mine's stuck open).

I've also tried cutting the line and putting a deep impact socket on the nut. That was disastrous. Broke the t-stat just like the picture above.

I can't stress enough to anyone working on these, if you're fortunate to get the lines disconnected cleanly from the t-stat? Be sure to use antiseize paste on the threads and the shoulder of the compression fitting (where the nut contacts it) upon reassembly!!!! A lot of times the line gets corrosion on it and does not let the nut spin freely. I occasionally loosen my t-stat nuts to avoid the freezing of the nut on the line.

KTL: good advice as to the internals of the thermostat...never knew this. THANKS!!!

Best,

I'm currently batting 1.000 on the last two times I've had to do this. That means the next one I have to do in the next couple weeks, I'm overdue for breakage or strippage. I've had good luck spraying penetrant into the threads and then heat cycling them for several days. Then comes the big hammer. Those compression fittings are nutted down incredibly tight, at least they are once that corrosion builds up. If you have a good local hose shop that can get metric fittings & parts, though, the best thing to do is to just dremel off the nut. Works like a charm and zero risk of damage to the threads if you have a steady hand with the cutoff wheel. Wayyyy faster too.

I would've done that except the line that wouldn't come off was going to be reused. The crimped line I was replacing came off fine.


http://forums.pelicanparts.com/uploa...1202499572.jpg

Youch!!! That's crimped but good! My advice was just 'in general'.

I had a set of lines a few years ago that I just tossed right in the trash. Both hoses were literally crushed flat for 4". Totally unsalveageable. How the heck does that happen???

Y'all seen some of the trick thru-the-rocker installs? No more crushed lines...

When I was a mechanic, the best soloution that I found for removing the pipes from the thermostat was to cut a slot in the nut with a die grinder or dremmel tool. You need to use care not to cut too deeply. In most cases I did not even cut all the way through it. I then uesed a large screwdriver to expand the nut. This is done by inserting the screwdriver into the freshly cut slot and twisting it.

The expanded nut then turns off of the thermostat without damaging the threads. The down side of this fix is that you need to replace the oil line with a new one, however, if it was stuck on there that badly...you probably should replace the line anyway (deterioration of the rubber hose section, leaking at the clamp, etc.). The upside is that you get to save the thermostat which is way more expensive and rarely requires replacement. Another benifit is that you get to admire the nice new annodized oil line...it looks so pretty! :-)

I came to use this method by bad experience after bad experience. I tried PB Blaster, heat alone, heat & cold, busted knuckles, etc. I have witnessed other mechanics deal with this issue...some of their efforts resulted in damaged body work, melted trim, melted undercoating, small fires, a broken finger and even a hernia. Trying to save the line (if it doesn't come off easily) wastes a lot of time too. If your time is worth money, your best bet is to sacrifice the oil line for the sake of the thermostat, your car and your sanity.

FC

I think it was $250ish? wasn't it steve? but still not pocket change

I agree with FC. I'm no mechanic but i've seen many of my local friends and alot of people on this forum mess with these oil lines because they want to save them. It's not worth it if you can buy the replacement line as easily as we can these days. Even though Porsche is starting to reduce their supply of replacement parts for these cars, I think aftermarket sources like SSF and the like will continue to supply these things.

mb911,

I was mainly referring to the oil line that comes from the engine to the thermostat or the one that goes from the thermostat back to the tank (soft lines or at least partially soft) with regards to the expanded nut fix. When replacing the hard lines (no rubber part) that go to/from the thermostat and the front cooler, the fix I recommended may not be the best fix depends on the condition of the lines. I guess I would ask why remove a line unless it is damaged. I know sometimes you need to remove one to have good access to the one you want to remove.

Even still, is the cost of the hard line worth the expense of the themostat and a hard line when you bust both trying to remove it? Philisopical question for those much smarter than I?

FC

When Comin In Hot and I broke his two years ago, it cost us $340 thru Motodelta. I don't think they've gotten any cheaper.