Uh Oh... snapped thermostat housing bolts.

[ultrarunner]

Shouldn't complain after 35 years of faithful service...

Only two bolts... right?... should be simple fix to R and R thermostat.

After three and half decades the bolts didn't give and both broke off.

Not being able to take in the 1985 Chevrolet Van for Smog Check is a problem... can't pay the $240 tag fees without a smog and be done... so paid the $22 fee to say the vehicle is off the road so penalties wouldn't kick in.

Access is a problem and heat is out...

Trying penetrating fluid like PB Blaster and need to figure out a way to drill out and tap...

Hate to part with the old girl after so many years and having it set up the way I need for work.

Still parked in the same spot as always... paint a little faded now.

 

[shovelmike]

The best penetrating oil I have encountered is Kroil, I get it in aerosol cans labeled Aerokroil. The first trial I gave it was on some very rusty brake line fittings, the came right off after soaking and allowing to sit a day or two.
Last time I had a situation like yours I drilled for easy out, and was still unable to remove the broken bolt. I bought a set of left hand rotation (ccw) drill bits, as soon as the bit took hold it spun the bolt out of there. A spray of Kroil and the CCW bit is my suggestion.

 

[dodge man]

If you can’t get them out look at a Helicoil to fix the bolt holes.

 

[snout]

Photos?

PB Blaster or Break-Free for 1-2 days otherwise apply heat. Lots of heat.
Use the drill-type extraction set where you drill into the fastener and tap in a rod that you extract with.

Ridgid makes the best setup, in my humble opinion. Snap-On re-brands them.
Screw Extractors | RIDGID Tools

 

[Rebeldad1]

Might be easier to help knowing what engine and what manifold. guessing 350 4bbl cast? Green coolant and again assuming the coolant wasnt serviced every couple years.
are the bolts broken above the manifold or below?
Since both broke they are probably rotted.
access really doesnt give you any control of drilling them out.
pull the manifold, replace or send to a machine shop.
Bet I'm not wrong.

 

[CoyPatton]

Old old old mechanic trick, apply heat—not ridiculously hot and melt candle wax into threads. If bolt shank is exposed and not rusted to pieces, vice grips may bring them out. If at or below surface level, you will have to drill and easy out or left hand drill bit.

 

[ultrarunner]

Driving down the freeway and blew a Gates heater hose... Changed hoses and coolant with water pump 4 years back... 75k miles is what I get on a new water pump.

Made a bypass repair and happened to have water so after waiting slowly topped off. Got about three miles with temp maxing...

Shut it down and called auto club... have the Premium 150 mile tow and then learned they would not be able to help... 5.1 miles from home... 40 years and not there when needed... hum???

Called my brother to come with my PJ trailer and loaded up for home.

PJ is 18' and for the Deere 110 TLB... at 18' is always just fits whatever I need with the operative words "Just fits" PJ is 12k downrated to 9980 pounds for CA... the Ford super duty diesel towed no problem even up 28% grade home.

My best guess is stuck thermostat as truck always runs cool and I put in a 4 row heavy duty radiator years ago...

305 V-8 with 4 barrel carb and Automatic G20 van.

Been soaking with PB for more than a week... when bolts snapped I called it a day. Outlet casting is still in place like it is welded on...

I can see where studs would be better in this application and will most will replace with studs.

 

[4570Man]

If you can’t get them out look at a Helicoil to fix the bolt holes.

A Helicoil is for stripped holes. They can’t fix broke bolts.

 

[Cat_Driver]

[video]https://www.google.com/search?client=safari&rls=en&q=penetrating+oil+transmisson+fluid&ie=UTF-8&oe=UTF-8#kpvalbx=_N8gkX8-UHZHL0PEP4Yy_8Ag33[/video]

 

[ericm979]

Left hand drill bits are great.

Before drilling you need to centerpunch the bolt. Especially since it probably did not break off nice and level. Since it's uneven, it'll need to be larger and deeper than a centerpunch on a flat surface. A carbide bit in a dremel tool works well.