Oil filter by-pass valve.

[Boomyal]

Spin on oil filters (oem full flow factory filter) are supposed to have a pressure actuated by-pass valve. If the filter were to become clogged the valve is supposed to open allowing oil(albiet unfiltered) flow thru to the engine. HAS ANYONE EVER HEARD OF THE VALVE STICKING OPEN? This morning, after a days play yesterday, I checked the oil and it was a little over the full mark on the dipstick. I thought that odd as the last time I changed my filters and topped off the oil (very recently) I checked it several times and it was right on the mark.<br /><br />Earlier this week I spun the filter off, to get access to motor mount shims I was playing with, and let it drain, partially, into a clean pan.(filter sits at a 40 deg angle or so) When I was done I screwed the filter back on and poured the oil, from the pan, back into the engine. The engine has been run several times since, including trips out Fri and Sat. Good oil pressure and engine temp the whole time.<br /><br />WELL, today, I spun the filter back off, to play with my shims somemore, and as I unscrewed the filter, with pan in place, no oil came out! Holding the filter upright, it is about 1/5th full of oil. Probably the same amount that was in it when I screwed it back on during the week.<br /><br />Well, I know all you experts are probably still out having fun, this Labor Day Weekend, so until you all return to dispense all of your collective valued knowledge, I'll just spin on a fresh filter, run the engine, feel the filter for hot oil going thru it, then recheck the oil level when I shut it down. Maybe I never will learn the answer but I thought I'd toss out the question just in case.<br /><br />Much Holiday Happiness to All

 

[metwrench]

Re: Oil filter by-pass valve.

Hmmmm, a Full flow Filter with Bypass ? Not that I have ever heard of...But i may be wrong.<br /><br />usually the ENGINE has the Bypass and will open Under High Pressure before the Filter.<br /><br />Strange<br /><br />John

 

[Boomyal]

Re: Oil filter by-pass valve.

John S.- Maybe I'm mixing up my understanding of the systems. I knew there was a by-pass, just thought it was in the filter not the motor. <br /><br />Nothing exotic here, just a 302 ford. All I know for sure is that I probably put 6-8 hours of run time on the motor after I screwed the hardly used oil filter back on. Now you have me worried. Changing the filter would have been an easy fix. By-pass valve in the engine sounds more complicated.

 

[metwrench]

Re: Oil filter by-pass valve.

well, Let me ask yout this, How was Your Oil Pressure ? Was in running Normal ?<br /><br />I am Just not 100% sure I am right about the Filter NOT having a Bypass, But in all my years of Automotive I have never heard of the Bypass in the filter...hey anything is possible.<br /><br />If your oil pressure is good and running Normal, I wouldnt be to concearned with this Condition. Heck, you can always TRY changing the Filter...<br /><br />Sorry for the worry..<br /><br />John

 

[Boomyal]

Re: Oil filter by-pass valve.

Well John, here, apparently is the ying and the yang of the situation:<br /><br />TECHNICAL INFORMATION <br />... Some engines have the by-pass valve mounted in the engine block, while others locate the by-pass valve in the filter. Automotive lube oil filters are ... <br /> http://cpgparts.alliedsignal.com/cpg/catalog/fram/... <br /><br />this from a google search on "automotive oil filter by-pass valves"<br /><br />I haven't read it yet 'cause it probably won't say which is which.<br /><br />My oil pressure was just fine, all as usual. I'll keep lookin for info and if I don't find anything more I'll try a new oil filter tomorrow.<br /><br />John-from just north of the other Salem (Oregon That Is)

 

[Boomyal]

Re: Oil filter by-pass valve.

a link that works:<br /><br /> http://cpgparts.alliedsignal.com/cpg/catalog/fram/legal/DiagnosingFilters.pdf

 

[Dunaruna]

Re: Oil filter by-pass valve.

The 302 has a pressure relief valve but no bypass valve. Filters do have bypass valves & anti-drain back valves, but not all brands. I dont know about fram, but ryco definetly has both (Z9). Aldo

 

[Boatin Bob]

Re: Oil filter by-pass valve.

Here is a link to an oil filter study done and the author included the type of bypass valve and anti-syphon valve used in each filter, looks like all the common popular filters have the bypass valve. Oil Filter Study

 

[Burbago]

Re: Oil filter by-pass valve.

As your engine cooled the oil contracted and sucked oil out of your filter.