I have justacquired a'91 S10 Blazer 4D 4X4 w/4.3L V-6 engine and it is in mint condition. The Blazerhasthe unique remote oil filter system.

My question is ...Where is that oil filter bypass valve located and how often does it need to be replaced? It is GM part number 25014006 and it appearsto have a small filter disc with it according to a photograph. I cannot find anything about the bypass valvein the 1991 S10 Blazer shop manual.

I also assume the remote oil filter should be the AC-Delco UPF52 Ultraguard Gold or equal.I installed a a NAPA (Wix) 1036 filter at the last oil change until I can obtain aAC-Delco UPF52 Ultraguard Gold oil filter from the dealership. A large Chevrolet dealership parts department had to order that oil filter because it is seldom used. The parts department counterman at the Chevrolet dealership never heard of it until I came in as wanted one. The local independent parts stores that sell AC Delco productsalso never heard of it. A NAPA (Wix) 1036 filteris cross-referenced to the AC Delco UPF52 Ultraguard Gold oil filter.

The AC Delco UPF52 Ultraguard Gold oil filter is about double the cost of the regular AC Delco PF52 Duraguard oil filter so it must be quite different.

Thanks in advance.

 

If it were me, I'd stick with the Napa (wix) or regular AC Delco filter. Spend the extra money if it gives you peace of mind, but...

Anyway... About the bypass. I cannot find any information on its location, but it should either be in the remote filter housing or in the adapter on the engine block. If you were rebuilding the motor, I would probably replace it. If you are just looking for things to replace, then that is your choice.

 

Thanks! That is a BIG help! That is exactly what thecounterman said at the Chevy dealership. He did not know anything about those parts either.

How can you make a recomendation about the oil bypass if you don't even know where it is?

I will definately use the expensive AC Delco UPF52 Ultraguard filteruntil I can someone to give me a ligicalreason why I should not use it. Besides, I have plenty of money to waste.

 

I can make a recommendation on the bypass without knowing where it is because I know what it does. The only time I have ever changed a bypass was when I was rebuilding a motor and this was only before oil filters came with internal bypass valves. It isn't something that is just replaced because you found a part number and decided to change it out. But hey, it's your money. Waste it as you will. And what part of "it should either be in the remote filter housing or in the adapter on the engine block" didn't you understand? Kinda narrows it down just a tad.

Give me a logical reason to spend twice as much money on the Ultraguard. If you follow the "It costs twice as much so it must be twice as good" theory, well... I guess I won't go there. LMAO! I'll just stop trying to help you out. I just wish I had as much money as you seem to have so I could be equally as frivolous with it.

That's a nice touch with berating me though. Good luck.

*EDIT* - This is it, I promise. I would just like to add that the PF52 & the UPF52 have a bypass built in...

 

Jerry, I don't have a diagram of the '91 engine, but on the '02 take off the filter adapter on the engine and there is the bypass valve. Pry it out, use a brass drift the same diameter as the new valve and seat it just slightly below flush with the block. Stake it at 3 equidistant points on the block and install the filter adapter. Good luck.