I think we all need to do some testing ! Our engines are being damaged at startup. This is a little long, but worth reading ( I hope :-)

After starting up the Max the other day and hearing way too much clatter, I decided to change the oil and filter as I thought the drainback valve (in the filter) was defective. The current synthetic oil and filter had about 3.5K miles and was due for a change in just a bit anyway.

I decided to test the (Wix) filter after pulling it out. So, I stood it on it's back and poured a little oil into the drainback valve area, enough to fill it. Then I waited. Within 3 minutes, all of the oil had drained into the filter ie., the drainback valve was almost free-flow. Since I was changing the oil in another two cars, I tested theirs also. All had about 3K miles on the oil/filter. One had synthetic with an AC/Delco filter. It was twice as slow as the Wix filter, but it still drained within five minutes. I tried the other Wix which had been in dino, it drained as fast as the first Wix.

Then I tested a new (Wix) filter. The oil did not go through the drain valve, even after 1/2 hour. It was nice and tight. I mounted it on a car, started it up to fill it with oil, and ran it a little. Then I removed it - still nice and tight, despite being primed.

So, conclusions: Since they say that most engine wear is at startup due to lack of oil, and since the drainback valves don't seem to do much after reasonable miles, I think we are all getting much more wear than we should. I am going to retest when my Nissan factory filter is at 3K miles and see how it does but I have my doubts that it will be any better than the others I tested. If I have time, I will try to test them all at 2K miles and see how much they are worn.

If you'd like to test, we all could benefit by your results. Next time you change your oil, just put the filter on its back and pour some oil into the drainback holes around the perimeter. Fill the rim area with oil, then watch to see how long it takes for the oil to drain. Report your results along with the brand of filter and miles driven.

Thanks,
Bob

 

Thank you for taking the initiative to test the anti-drainback valve in your oil filters. However... and I want to say this tactfully... I think you did the test backward and therefore your findings are meaningless.

According to a diagram in the '99 Maxima factory service manual the filtered oil flows out of the large center hole in the filter base plate. From there it goes upward, filling oil galleries in the engine block and cylinder heads. The ADV is a check valve, a one-way valve. It is supposed to permit free flow of pumped oil in the "uphill" direction and block gravity-driven return flow when the engine is off.

A more useful test would be this...
- Fill the filter with oil (used oil is fine for this test).
- Seal the center hole with a bolt or rubber plug of appropriate size.
- Lay the full filter on its side in a catch pan.
- No oil should escape from the filter.

 

Where's sinewave?

 

hmm...i think i did something similar to this every time i do oil change. After taking off the old filter I'd try to drain all the oil out of it before throwing it away. Each time I turn the filter so the holes would face downward, only a small amount of oil drain out, and i think it's draining out the middle hole, then i'd flip it up again to let the oil settle to bottom of the filter. I'd have to repeat this process a couple of times before most of the oil are out of the filter. So it sounds like the anti-drainback feature is working on the OEM filter.

 

Great info on this guys.

Now do all filter have drain anti-back valves? I would assume majority if not all filters have them right? If they do, then what is the sense in going to the dealer to use OEM filter?

 

All filters of all brands which are intended for use in the inverted or horizontal position have an anti-drainback valve.

 

Hmmm, Daniel, I see your theory. Some more research is obviously required on this :-)

I hope you are correct, I'd feel much better about my filter(s) and engine.

Bob