The oil filter bypass valve is not this part?

 

I wouldn't call it "rare", probably several million of them were built. It might be a rare request due to techs being unaware of it and what it does. The 4.3L has been around since 1985 and it's a V6 version of the V8 350. Same bore and stroke, and I wouldn't be surprised if the 350 uses the same valve.

 

So this valve is part of the engine not, the remote cooling system? if so this may be what killed my engine earlier this year.

 

The valve is pressed into the engine block. Pressurized oil leaves the oil pump, and if the valve is stuck open, a certain percentage of oil is directed, (bypassed) right back into the oil pan. This causes oil pressure, (and volume) to the engine bearings, to decrease. If the valve sticks closed, oil pressure will rise and explode the oil filter and/or cooler lines. Think of the valve as an oil pressure regulator, it keeps oil pressure from getting too high

 

Been looking at RockAuto and is the part you're referring to the opil filter bypass valve? From the pix, it looks like it has to pressed in.

 

If the oil filter is remote mounted, (under the radiator) there is a normally closed bypass valve in the remote mount. If/when the oil filter becomes clogged, the valve opens. Oil is then circulated through the engine without filtration. When this valve opens, oil pressure is not affected to the point where you'd notice a drop. GM part #25013767.

The other bypass valve is pressed into the engine block, (requires oil filter adapter removal). Its purpose is to prevent the oil from over pressurizing and blowing the oil filter apart. The valve is normally closed, but if it sticks open due to a weak or broken spring, sludge build up, etc, pressurized oil is directed back into the oil pan so the oil filter will not blow apart. As a result, oil pressure drops and oil starvation to the engine bearings will occur. GM part #25014006.

 

Damn...if I didn't know any better, I think you know what you're talking about...lol

 

Been there a time or two The one on the remote mount is simple to replace, but the one in the block... not so much... a real PITA is more like it, unless the engine is out of the vehicle.

 

Is the one in the remote the same as the one in the engine block? Is it just the one?

 

Same basic physical appearance and size, but different spring pressures.