What's it do? I put the intake back on my engine, and one of the two bolts on this valve got a little stripped. It's tight, but I hit a point where it just started to spin and not get tighter. Obviously it should be snug, but I'm just making sure it's not something carrying fluid, or is completely essential to having the truck run right. I'm just trying to get away with not buying helicoil or some kind of tap just yet.. It's on my 22R

 

Do you mean the thermostat?

If so ... coolant runs through there ... under pressure. If it's not tight, you're gonna have a major coolant leak.

 

No....there's something that attaches to the intake side of the head, that you can get to once the intake manifold is off. It's got a couple vacuum looking hoses coming off the top, and a long hose that goes down off the bottom. It attaches to the head, using part of the intake manifold gasket. I've got an '85 FSM I'm working off, and it calls it the thermostatic valve..I think. It's got two drawings on that page, says to take the egr off off, then the intake manifold, then the thermostatic valve. I'm just guessing the first drawing is the egr, and second is what they're calling the thermostatic valve.

 

How about BVSV? I'm seeing a diagram calling it that...