thermostat housing

[jag7720]

my thermostat was stuck open thus I could not get above 150 degrees today..

So I am changing it out and the bolts broke off. I have about 1/2 inch sticking out... my question is... how do I go about getting the rest of the bolt out?

I tried heat/wd-40 and vise-grips.... no good
Thanks

 

[m38inmaine]

Drill them out and re-tap. Be sure to use the correct drill size for the tap, use a piece of tape on the bit to gauge the depth if the hole is blind, be sure to center the drill as well. Start with a pilot drill such as 1/8" and use cutting fluid. Be sure to keep the drill straight and just take it slow. I am note sure if the bolts are metric or inch. Good luck.

 

[CUCVFAN]

They're tough to drill straight. I would try some more heat and some penetrating lube like Kroil or Gibbs or even PB Blaster. Dissimilar metals don't get along, especially there...

 

[mangus580]

I have one someplace.... I wonder if its covered in snow right now...

 

[jag7720]

ok... once I get it all back together does the black puck side of the thermostat go in the engine side of the housing or the radiator side?

 

[corelokt]

It's always possible to drill out as much of the bolt as possible, and using a pointed punch, actually tap the remaing bolt out of the threads. Another way is to drill a small hole down the side of the bolt, right at the threads and bolt. Fill with penetrating oil, ie. kerosene, and then cut a screwdriver slot into the protruding part. Use heat until it's getting red hot, and turn it out. I've done both at times. If the bolt is going into aluminum, I'd try the first one.

 

[mangus580]

If you have 1/2" sticking out, I would not go to the drilling game.

Get some really good penetrating oil, heat/soak many times. I have even heard of people heating it very hot, and dripping melted candle wax into the threads...

You still have plenty of bolt to grab on to... I wouldnt try to drill it out until that changes.

 

[ralbelt]

I've pulled steel bolts out of aluminum blocks by soaking with penetrating oil then mig welding on a nut then and backing it out. If I have to drill I make sure to drill completly thru the broken bolt that way I can get the lube to the other end of the bolt.

Also used the same procedures on cast iron and steel.

 

[jag7720]

Well, I ended up having to drill thru the old bolts and and putting a nut and bolt on it to hold the housing in place until the earth thaws... I spent 5 hours outside in 7 degree weather working on this... it is my daily and my the cold killed my wife's van so I had to complete it.

Anyone have a spare thermostat housing that does not have bolts broke off in it? The piece that mounts to both heads.

Thanks

 

[corelokt]

You've got me worried. Mine needs a thermostat too.

 

[jag7720]

At this point, had I know what was going to happen, I would have gotten some really good penetrating oil and did a cycle of

penetrating oil
heat
penetrating oil
heat
penetrating oil
heat

repeat many many times

then slowly back out the bolt then

penetrating oil
heat

then back in with the bolt ... then

penetrating oil
heat

then back out a bit further

and repeat.