Anti drainback valves

[D-Roc]

I notice some filters have anti drainback valves. I was changing my oil not long ago (was using Donaldson ELF7349) and noticed it was not full to the top when I spun it off. The level was not low, but not right at the top either... I have noticed this in the past as well, but uoa has not shown any significant wear with the Donaldson or any other filter I have ever used. I emailed Fleetguard (which I use as well) and they mentioned that none of the filters used for my particular year have the anit drainaback valve.
So what is the consensus? Do anti drainback valves make any difference in the performance of an oil or filter? Why don't all oil filters have them?

 

[Mike_dup1]

Wix says it helps keep oil in the filter to help prevent dry starts. Its a anti-reverse flow device.

The engine manf. figures its not needed I suppose.

 

[Gary Allan]

You must have a vertical mount. Once the air gets to the center tube, the siphon is broken. No more back flow. For all you know, it drains "forward" and bubbles eventually make their way back to the filter and evacuate the small amount that you see missing. I'd tend to lean toward the very limited back siphon explanation.

 

[D-Roc]

Yeah, it is a vertical mount...how do you mean by the "limited back siphon explanation"? If I'm reading you right, Gary, once the engine is shut off, there might be a bit of flow going forward and that is why I end up with a bit of the top of the filter drained out when I do an oil change. I guess the pump can only do what it is designed to do when the engine is running, then gravity takes over, and it cannot be brought back.
So, in my case, would an oil filter with an antidrainback valve be of any benefit? If it was, I guess the Fleetguards would have said valve, it is after all, a Cummins.

 

[Gary Allan]

The oil can go in either direction depending on how the plumbing is configured, but if it was going to be a substantial flow, they would have a ADBV. There can't be a lot of oil cached in the engine above the filter ..or so I reason. If you had some massive oil column above the filter that couldn't drain any other way but through the filter, without an ADBV, you would be back flushing the media every shut down. ADBV's don't typically have to hold indefinitely, the OEM spec's (unless silicon ADBV's are part of the OEM spec) typically just require them to hold for so long ..as in controlled/slow backflow.