TheSamba.com :: View topic

Sun Sep 27, 2009 11:04 pm

I tested a thermostat in boiling water the other day, but didn't know it should have been tested in the bracket.

Is it true that if they are allowed to expand without being in the bracket, it renders them useless?

Thanks

Sun Sep 27, 2009 11:12 pm

Well now that it has cooled down an easy "test" will be to see if it shrinks back down to normal size. (collapsed) If it stays expnded then it is hooped and you can either try to fix it; find a good used one (tough), or convert to the type 1 thermostat.

Good Luck

Sun Sep 27, 2009 11:17 pm

It's a Type 1 thermostat and I managed to get it from the local VW shop.

I'll probably have to remove it from my bus and test it again in the morning before work, which is no fun at all.

Mon Sep 28, 2009 4:54 am

As Davis911s says you don't have to test your thermostat, all you have to do is look at it. If it retracts when cold so that the pleats are tightly together it is fine. If it doesn't retract it has a hole and is bad.

Mon Sep 28, 2009 6:33 am

Just checked this morning. It definitely failed. It's completely soft and I can expand/contract it by hand. Luckily, it failed properly on the only drive I took it on and the cooling flaps were open.

Unfortunately, I threaded it so tight that the thermostat is just spinning around and the female end is just seized on the rod. Now I have to figure out how the hell to get it off...whether to saw it in a hand-sized space or some other solution. Gripping the hell out of the female end with pliers seems to do nothing when oil is present.

Mon Sep 28, 2009 8:56 am

Kind of late for this advice, but somebody here mentioned testing the thermostats with a hair dryer. I have done that for the last 2 thermostats I found in the junkyard and cranking the wife's hair dryer up to max and heating the bellows made the thermostat expand. Luckily they both contracted nicely when cooled.

Mon Sep 28, 2009 10:06 am

regalasr wrote: Kind of late for this advice, but somebody here mentioned testing the thermostats with a hair dryer. I have done that for the last 2 thermostats I found in the junkyard and cranking the wife's hair dryer up to max and heating the bellows made the thermostat expand. Luckily they both contracted nicely when cooled.

Very good advice. The guys at the shop said that water usually ruins them and to test them using hot air instead.

I was dumb and watched a YouTube video where a guy used hot water to test his. I did the same. I wish I had known ahead of time that it was a bad idea.

Mon Sep 28, 2009 10:18 am

By the way...I just bought a dremel tool and some accessories for $85. :(

I'm going to work as hard as possible to remove that thermostat without having to open the dremel box so I can get my money back. 8)

Mon Sep 28, 2009 12:41 pm

Dremel tools are nice to have, why take it back?

So, the problem is that the thermostat won't detach from the rod, it just spins around and won't unscrew? I wish I had a thermostat in my hand to see. Don't the thermostat bodies have a pressed in steel thread female boss, and that's what's turning inside the thermostat body???? I can't remember, but it would make sense. The damage was probably done when you overtightened the thermostat.

See if you can get some long nose channel lock pliers up in the there to hold the rod and then tap down on top of the thermostat and see what happens. If you ruin the threads on the thermostat rod then you'll need to replace that, not an easy thing to do in one day. Very close quarters up in there, best of luck.

Tue Sep 29, 2009 12:03 pm

Sorry for the late reply - I didn't get a mail notification and I took a day to rest. Next time I'm wearing a mask. Gasoline and exhaust fumes knocked me flat and I spent yesterday on the couch.

Jody '71 wrote: Dremel tools are nice to have, why take it back?

So, the problem is that the thermostat won't detach from the rod, it just spins around and won't unscrew? I wish I had a thermostat in my hand to see. Don't the thermostat bodies have a pressed in steel thread female boss, and that's what's turning inside the thermostat body???? I can't remember, but it would make sense. The damage was probably done when you overtightened the thermostat.

The now-spongy expandable part is just spinning around the female rod end. And next time I'll just thread it til it can't be threaded anymore, and I'll make sure not to take that extra twist. Lesson learned.

However, I ruined the thermostat when I put it in water without the bracket. That pretty much did it in.

Quote: See if you can get some long nose channel lock pliers up in the there to hold the rod and then tap down on top of the thermostat and see what happens. If you ruin the threads on the thermostat rod then you'll need to replace that, not an easy thing to do in one day. Very close quarters up in there, best of luck.

Thanks - good tip. I've been told to get channel lock pliers, so it's probably about time.

I'm trying really hard not to ruin the threads on the rod. The last thing I want to do is disassemble the rear scoop again and remove the shroud and generator once more. I've done it about 4 times this summer now, and it's a pain in the ass.

Sat Oct 03, 2009 1:27 am

Yesterday (Friday) I went and tore off the failed thermostat and mounted the replacement:

Can anyone please tell me if I should be concerned about the slight angle, or should I try to straighten it out more? I've tried to keep the bracket from causing an angle on the thermostat, but I haven't had the best of luck.

Sat Oct 03, 2009 6:19 am

Only concern would be the rod binding in the head tin piece cutout or where is passes through the head. Do the hair dryer test, get inside and pull your top engine hatch off and look down and watch to see how easily the flap assemblies open while the hair dryer heats up the T-stat. You do
have the return spring on that connects the crossbar to the shroud, correct?

Sat Oct 03, 2009 7:36 am

Jody '71 wrote: Only concern would be the rod binding in the head tin piece cutout or where is passes through the head. Do the hair dryer test, get inside and pull your top engine hatch off and look down and watch to see how easily the flap assemblies open while the hair dryer heats up the T-stat. You do
have the return spring on that connects the crossbar to the shroud, correct?

sure do. I'll test it out and see how it does

Sat Oct 03, 2009 7:50 am

See Bentley, chapter 5, pages 18- 19, section 6.1 "adjusting thermostat."

Sat Oct 03, 2009 8:19 am

I read Ratwell awhile back and these thermos are air temp sensitive and should be kept away from water testing. Hot water heats far too rapidly and cools far too rapidly if cold water is applied afterwards which apparently stresses the thermo to the point of failure.

Sat Oct 03, 2009 9:48 am

Just went out there and wasted time trying to heat it with a blow dryer and it didn't expand.

I then warmed up the engine and throttled from time to time for about 10 minutes and gain it didn't expand.

I drove it around the neighborhood for a bit, and even then it didn't expand.

I now understand completely why people get frustrated with these things and remove them and throw them away.

Instead of doing something productive with my morning, I'm wasting time under my bus trying to coax an inanimate object to do its job. I could be doing better things with my time.

If this thing doesn't expand, I'm taking my chances and removing it. If it means I'll get closer to a rebuild sooner, then so be it.

Sat Oct 03, 2009 12:06 pm

Stop being so anti thermostat. You could have a bum new one. Or a bum used one. Take the T-stat bracket assembly out of the engine with the new thermostat still installed into the bracket and hit it with the hair dryer. See what the T-stat does. If it doesn't open up it is no good. If it does, then you have linkage problems.

Sat Oct 03, 2009 11:02 pm

Uh, you do know about shrinkage, right?
:P

Tue Oct 06, 2009 8:48 am

The system is finally working after removing/installing and removing/installing over and over again.

In the morning, things weren't quite right on the ride into work, so after I got off, I bent the bracket to get it to keep the thermostat as straight as possible and mounted the thermostat again.

Got home, saw the thermostat expanded all the way, and the cooling vanes were fully open. Checked after some hours when everything cooled down, and they were fully closed.

Case closed on this one. Hope this thing lasts me for a good long while now.

Tue Oct 06, 2009 10:13 am

Often times you do have to tweak things a bit for everything to move smoothly without kinks or binds. Congradulations for completing the "Installing Themostast, Rod, Linkage and Flap Assemblies" ordeal. You have to get meticulous in such instances, but your engine will be very appreciative now. :D :D