Join Date: Jul 2006
Location: Northfield, Illinois
You need to be careful with stuck thermostat removal. Many good manifolds have been cracked by too much force. I repaired one that had the threaded end snapped off! If it does crack perpendicular to the threads, it can be repaired by welding, but there is NO tap to recut the threads. I used a mill to cut the penetrating weld out of the inside, and then a jig on my lathe to lathe re- cut the threads. And a fun job it was not! The snapped off end was easier. I machined an aluminum tube to look like the outside of the manifold end on my lathe, then without a fixture and the whole manifold flailing about, cut threads only deep enough for the new thermostat. I then tack welded it to the, now cut smooth manifold, and ran a penetrating bead around. Then with a die grinder I refinished only the outside. After a course carbide media blast, followed by a finer glass bead clean up, it could not be told from new.
If you have rounded off the brass, drill out the guts until you have just a brass liner in the aluminum. You may have to use a carbide bit in a die grinder to get this nice enough to work on. Then use a sawsall CAREFULLY. You will cut through the brass into the aluminum, and you will need THREE cuts. Then you can knock the pie shaped pieces out with a punch. That done, clean the damaged threads with a sharpened right angle steel pick, LUBRICATE the threads with silver anti-seize, and screw in and out a new thermostat, until it fits flush. As mentioned above DO NOT tighten it! The anti seize will fill the cuts in the threads, and it will seal just fine for normal use.
I got tricky once, and after getting the new thermostat to go in and out easily, I cleaned everything with solvent, painted the thermostat threads with Epoxy Release Compound, filled my saw cuts with JB Weld, and screwed the thermostat in. Next day it actually came out easily, and the threads were restored. I smeared silver anti-seize on and reassembled the final time. This last trick is not really necessary, it's just nicer than saw cut damage in threads.
From my experience.
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