Recently I was doing some reading about oil pressure and the purpose of the bypass valves on the "Oil filter Remote relocation mounting bracket". Here's what I understand:
When you start your car on a very cold day, your oil will be quite thick and can't flow through your oil filter media. So then the bypass valve will open up and let the oil by-pass the filter until the engine has warmed up and the oil has thinned out enough to now pass through the filter. Also, if you haven't changed your oil filter for a long time and it is now completely plugged up, the bypass valve will open to let the oil by pass the filter and allow the engine to be lubricated.
I asked a mechanic about this. He said that when he does an oil filter change on a Blazer with this by-pass valve, that he would insert the straw on a can of carburetor cleaner into the by pass valves to clear any obstructions or debris that may become lodged in the by-pass valves
I gave it some thought and decided that I would order two of these by-pass valves (ACDelco 25013767) and replace them the next time I did an oil and filter change. I have a little over a hundred thousand original miles on the engine and like to change out parts when practical as preventive maintenance, which leads me to my question... Has anyone attempted to replace these valves? and if so I'd appreciate info regarding the process of removing them and then installing the new valves. I tried to remove mine with a hooked pick type tool, but had no success and got frustrated with it, gave up and put the filter on before it pissed me off and caused me to break something lol.









Thanks in advance for any suggestions

 

The bypass valve is located in the engine block, not at the remote filter mount. The oil cooler line and the adapter must both be removed to expose the valve. It is staked in 3 places to keep it in place. It can be rather stubborn to remove, but it just pulls straight down. You'll need to replace the gasket, O ring, etc etc Dorman Products - 82560

EDIT: Another little tid bit about the valve: if the spring weakens or breaks, bypass pressure will decrease and cause the oil to bypass the filter at a much lower pressure, and could bypass all the time, resulting in no oil filtration. If you remove the spring and put a flat washer under the spring, then reinstall the spring, it will raise bypass pressure.

 

Does anyone know what pressure a my 1994 s-10 Blazer's oil filter bypass spring (the one imbedded in the block) opens at and if it can be changed to a higher rated spring? It would also be appreciated of anyone might have a part number as well.
Problem: No oil pressure at idle ->ramps way up off idle (re. city driving). Disassembled the engine (has low miles) ->roller cams journals severely gouged. I youtubed the problem and a video pointed out problems with the front mounted oil filter's bypass spring.
Any help is gratefully appreciated.
Thanks,
Frank

 

Does the bypass not always open partially, even with a new filter and hot oil? Something I remember from way back, so it may not be entirely accurate...

 

I wish I had know this two weekends ago! I had the adapter out to replace the gasket on it. With 250K on the clock, I would have gone ahead and changed this while I was there.