Thermostat bolts are 3.2. Break one for a helluva mess. Remove intake manifiold to replace thermostat housing for about $60 parts cost.

Or drill out and easy out the broken bolt. Oh yeah! I've done more than a few broken bolts. This was not possible. Can't get any heat to it.

Solution: Drilled out the top left bolt and formed nut that would fit behind the flange on the thermo housing. REplaced the other two with 8.8 stainless.

Net: If you have a chance get the stainless in early.