Where does the Oil Filter Bypass Valve (GM-25014006) go that is only usedwith the 4x4 with the remote oil filter and oil cooling system. The exploded view of the remote oil filter system in the 1991 Shop manual is inconclusive and unclear. What is it's function? Why is is only used on the 4x4 with remote oil filtration system?

 

I believe it is located where the oil filter normally is on the engine. the oil filter itself is located in the front driver side corner under the hood and my valve is where the oil filter usaully is. mine is A 94. it should be the same

 

Thanks..That is where I suspected the little by-pass valve was located.

My conclusion about the reason for the auxillaryby-passand anti-drain back valve is this: Since the 4x4 Blazers do not have a oil filter with a built-in by-pass/anti-drain back valveon the engine,the purpose of the auxillary by-pass/anti-drain back valve that is located in theoil line to engine adapteris to prevent over pressurizing the oil pumpdue to the more restrictive flow through the remote oil filter and oil cooler system. It is also used to prevent oil from draining back into the engine from the remote oil filter-oil cooler system after the engine is shut off.