[Vwdiesel] thermostat blues

[James Hansen]

If the bolt has been in there forever, then it's welded itself in 
through trading electrons with the aluminum.  Okay, not trading 
electrons, it's more of a tax on the aluminum, but you get the picture, 
the aluminum oxidizes, the oxide takes up space, the bolt is more or 
less stuck because there is no room for the threads to move.

Here's what I do, arranged in order of potential for destruction....

In this list, you may note the absence of drilling holes in the bolt and 
using an extractor.  In my opinion, it is less destructive to use a 
welder than to try to use a horribly mis-named tool called an "easy-out" 
   There is nothing easy about an easy out...
It would go last in my list, but since I have never had need to go past 
the last procedure, they stay in my tool cabinet where they belong. 
Nice shiny pieces of crap to sell to someone else at my estate sale.
Don't agree? Try getting a broken easy out out of a blind hole in an 
expensive part without an EDM.  BTDT, and won't do it again. fooey.

So anyway...

Line up a good flat punch on the bolt and give it a couple stout whacks 
with a heavy hammer.  Not destructive, just not some little love tap 
that barely moves dust. You should have no trouble seeing the punch mark 
on the bolt.  THEN grab it with the brand new special shiny brand name 
"Vice Grips" that you keep stashed away in your tool chest just for such 
an occasion.  The jaws should be clean and sharp to do this.  Old worn 
jaws covered in weld boogers will not grab enough to be effective.

If this fails, out comes the torch.  Propane is good enough.  Home 
handyman type you would use for plumbing- but the hot ones that make a 
bunch of noise when they burn and have a peizo igniter on them, not the 
old style units that are comparatively cool.   Heat the end of the bolt, 
get it as hot as possible- you are trying to get the bolt to expand as 
much as possible, and squoosh the aluminum oxide in the thread spaces to 
make room for the threads to move.  Try not to burn the car down doing this.
When it's hot, smoking, and about to melt, stop.  give it another coupla 
whacks with the afforementioned punch and hammer. the shock is important 
to the loosening process.
Now, LET IT COOL.  Completely.
Go for coffee, or support your favorite beverage company.
When it's cool, try the vice grips again. You could put some oily stuff 
miracle loosener, but by and large, they are mostly ineffective on stuff 
that is oxidixed into place by dissimilar metals.

it should come out.

IF NOT, then out comes the mig welder.
Weld a nut to the broken stub, even it is flush with the surface, or 
even a little below surface.  Plug weld the nut on completely, the weld 
will not stick to the aluminum, but will stick to the broken bolt... but 
you have to actually weld, not just squeeze geese onto it. Get someone 
competent to do it if you are unsure. The bolt and nut need to be as one.
This accomplishes two things.  It heats up the bolt better than you did 
with the torch, and provides a place to use a wrench on.
Give the nut a whack when hot, and let cool again. It will now come out 
and you will wonder why it was so tough.  Welding on a nut has NEVER 
failed me in everything from bolts in aluminum, to D8 cats, to heavy 
trucks, and steam engines, in steel, cast iron, aluminum, stainless, pot 
metal, brass, and others.

On reassembly, use antiseize, and you will never have to fight with it 
again.

Hope this helps :-)

-James

Pam & Doug Boes wrote:
> I think my thermostat was stuck closed. I pulled off the lower hose and only
> a dribble of coolant came out. I tried to remove the thermostat housing but
> snapped off one of the screws. Plenty of coolant came out of the radiator.
> Does anyone know any tricks for removing screw stubs from the water pump
> housing w/o removing the housing from the engine of the Caddy? I've doused
> it with PB Blaster and plan to grab the stub with vice grips and try tapping
> it loose. 
> 
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