Air through oil bypass valve normal?

[PDRig]

I have a motorcycle with a shared engine/trans oil sump and it uses a small paper cartridge filter in the engine case for oil filtration and i just got replacements to change the oil. Never thought to do this before, but since this is a small open type cartridge filter with bypass valve at the top. I put the new filter up to my lips and blew on it. Air blows right through 3 of the 4 new filters. A lot of air like the bypass is cracked open. I have a collection of old filters in 5 gallon can with a screen bottom so the oil can drip out, prior to discarding. So i went and found the last 2 i changed out on this bike. I cant blow air through either of those bypass valves. no matter how hard i try. I am thinking if air can get through on these new filters, oil will most certainly get through and be bypassing the entire time. Now to my question.

Should air be able to get by the seal for the bypass so easy on a new filter?

I called Wix, and the woman I spoke to was perplexed by this question, which was interesting because they specialize in filters. They woman told me that if i think there is something wrong with it to just return it to the store, but could tell me one way or another if it was normal to just be able to blow air through the bypass very easily.

My thoughts are the bypass should be sealed almost completely unable to let major air (or oil) through unless there are 2 conditions. 1. the oil is cold and the oil is having a hard time getting through the media at that time untill the oil warms up. 2. The filter media is clogged causing a pressure differential between inflow and outflow of the filter.

For reference, the 2 old filters i have that the bypass valves are tight as a drum are yamaha branded filters. These new filters that i can blow are through the bypass valves are wix.

 

[ZeeOSix]

Did you try to actuate the bypass valve a few times to see if there was anything hanging it up, and then check it again to see if it would seat better and stop leaking?

 

[PDRig]

Did you try to actuate the bypass valve a few times to see if there was anything hanging it up, and then check it again to see if it would seat better and stop leaking?

Yes sir. The used oem Yamaha filters I still have are tight as a drum. No air able to pass at all. I do not have any new ones to check if the bypass valve allows anything through. No matter how hard you try. 3 out of 4 of the wix filters I can just blow air though. I depressed the center of the bypass vale a few times and attempted to spin it. Didn’t make a difference. And when I called wix they told me that they could answer my question because no one has ever asked before.

My question being. Should oil be bypassing the filter all the time? I would assume that the bypass valve mating surfaces are not going to break in. The differential oil pressure will always be lower on the inside of the filter, so I am thinking these filters will always be bypassing unfiltered oil to some degree which I am not sure is normal.

 

[ZeeOSix]

Yes sir. The used oem Yamaha filters I still have are tight as a drum. No air able to pass at all. I do not have any new ones to check if the bypass valve allows anything through. No matter how hard you try. 3 out of 4 of the wix filters I can just blow air though. I depressed the center of the bypass vale a few times and attempted to spin it. Didn’t make a difference. And when I called wix they told me that they could answer my question because no one has ever asked before.

My question being. Should oil be bypassing the filter all the time? I would assume that the bypass valve mating surfaces are not going to break in. The differential oil pressure will always be lower on the inside of the filter, so I am thinking these filters will always be bypassing unfiltered oil to some degree which I am not sure is normal.

If you actuated the bypass valve and ensured nothing was hanging it up and it still leaked, then I wouldn't use them either. A bypass valve should be able to hold a slight amount of air pressure (like blowing with your mouth pressure) without leaking, and that proves to be the case with the OEM Yamaha filters you also tested which didn't show any signs of leakage.

 

[PDRig]

Suspected as much. The bypass should be opening only in the event that it actually needs to bypass a clogged filter, or bypass Delta across the filter due to thick oil during cold start. Thanks for your interest and reply.

 

[ZeeOSix]

I just did a similar test on 3 cartridge new oil filters I have here for my Kawasaki KLX300. Blowing with my mouth, I couldn't detect any real air leakage. And they are just a metal-on-metal seal on the bypass valve.

 

[PDRig]

Yes sir. Wix filter 57933. Small cylinder shaped open paper element. Metal to metal seal on the bypass valve at 1 end. Air blows straight through 3 of the 4. The fourth filter has moderate resistance when I blow on it, but air still gets by. Which in my mind if air is getting by. Oil is getting by. Mostly filtering is better than no filtering, i suppose. Tech support said they have never had anyone ask this question before. Said they are not sure if it is supposed to do that, and that if I think something is wrong with the filters to just return them. Pretty much dismissed it. Odd that a filtration company, didn't know how their product should work, nor did it care that its filter apparently is not filtering very well. Their quality control on this specific filter does not appear to be good. 3/4 of the filters are bad on the bypass. 1/4 is not as bad as the other 3, but still has an open bypass. For what its worth. 2 filters were produced in Indonesia. The other two are a product of China. Made in is printed directly on each filter.

Did you go with Kawasaki branded filter for the KLX?

 

[ZeeOSix]

Yes sir. Wix filter 57933. Small cylinder shaped open paper element. Metal to metal seal on the bypass valve at 1 end. Air blows straight through 3 of the 4. The fourth filter has moderate resistance when I blow on it, but air still gets by. Which in my mind if air is getting by. Oil is getting by. Mostly filtering is better than no filtering, i suppose. Tech support said they have never had anyone ask this question before. Said they are not sure if it is supposed to do that, and that if I think something is wrong with the filters to just return them. Pretty much dismissed it. Odd that a filtration company, didn't know how their product should work, nor did it care that its filter apparently is not filtering very well. Their quality control on this specific filter does not appear to be good. 3/4 of the filters are bad on the bypass. 1/4 is not as bad as the other 3, but still has an open bypass. For what its worth. 2 filters were produced in Indonesia. The other two are a product of China. Made in is printed directly on each filter.

Did you go with Kawasaki branded filter for the KLX?

The oil filter I got from the Kawasaki dealer is a "Fire Power" brand, so probably made by a larger maker under that brand name. It's made in China, but it looks well made.

The other two are HiFlo brand, which I got on Amazon. HiFlo is a well known filter brand in the motorcycle world. It's made in Thailand, and very nice looking filter. K&N brand filters for my KLX look similar to the HiFlo with the red colored media.

I would suggest trying the HiFlo brand for your bike if they are available.

 

[PDRig]

I decided to bring it back to basics, and go with the Yamaha oil filters just to make things easy as the dealer is right down the street from me. All the filters i just picked up, you can blow as hard as you can on the bypass valves. No air gets through what so ever.

The Wix equivalent 57933. A large amount of air can be blown through without much effort. Be advised if you like for your engine to received filtered oil, Beware of the wix powersports 57933. Either I got a bad batch, or they are manufactured in a facility that has a worn mold and quality control that does not check the bypass valves......

This Wix filter 57933 fits pretty much all the 4 stroke Yamaha YZ engines from 2002 to present I believe. Cheers.