Removing a stuck temperature switch

toyota
pickup

#1

The temperature switch screws directly into the outside of the engine. It’s made of brass. I broke mine. I have a replacement but I can’t get the old one off.



It’s 17 mm. I tried first a 17 mm box wrench (12 point) which didn’t budge it

but scraped off metal.



I bought a 6-point socket and used my 18"

breaker bar: still couldn’t move it.



I assume it’s the original part, which means it has been there for 23 years.



What do you good people suggest?



It is regular threads: I haven’t been

trying to screw it off the wrong way.


#2

First, try TIGHTENING it a little, then back it out… Next try an impact wrench…This may twist it off flush…Not a good thing. Maybe try heating it to near incandescent heat with a torch. That almost always works…


#3

This is a perfect example of what can happen when two disimular metals are threaded together. Such as steel drain plugs screwed into aluminum oil pans. I run into this when trying to remove stainless steel sensor fittings out of steel bungs. You can get the brass sending unit out of the block but it’s going to take heat.

Take a propane torch and heat up what’s left of the sending unit as hot as possible. Let it cool back down and try removing it. If it doesn’t budge, spray a penetrating lubricant around the threads. Reheat and let cool down and try again. Repeat again. Eventually the sending unit will come out.

Tester


#4
 Quoth Caddyman:  'First, try TIGHTENING it a little, then back it out.'
 Did. 

 Quoth Caddyman: 'Next try an impact wrench.'
 No room to maneuver, unless I lift the engine

 Quoth Caddyman: 'try heating it to near incandescent heat with a torch.'
 Heat my engine with a torch.  You're a fan of excitement at the expense

of others.

 It's brass: I could dig in with something that would grip it hard - but

not too many times: what’s the best way to try?


#5

Sometimes the factory uses a sealer or thread locker on these fittings. High heat will break this bond. ANYTHING threaded into aluminum will tend to seize in place. Bringing the brass up to high heat can loosen this bond also…

Maybe step up to 1/2" drive tools to get more leverage.


#6
 Quoth Tester:  'Take a propane torch and heat up what's left of the sending unit as hot as possible.'
 I've learned to respect Mr Tester from the experience and judgment of his posts, but I

can’t imagine taking a torch to my engine. Would I have to drain it of oil first? and
gasoline (how? I have already disconnected the fuel pump to get at the temperature switch.)

 Quoth Caddyman:  'ANYTHING threaded into aluminum will tend to seize in place'
 The engine is iron.

 Quoth Caddyman:  'Maybe step up to 1/2" drive tools to get more leverage.'
 I've been using 1/2" drive all along.  That's not the problem: the wrench

and socket have ground metal off instead of moving the part.

  I'd prefer something that gripped the part as hard as possible but not so

hard as to bust it off.
There seems to be something between the nut and the engine, like a washer
or gasket, but these aren’t mentioned in the manual and the replacement came
with nothing.