Oil filter mounting & anti drain back valve

[froggy47]

Most oil filters for the past 50 years or so mount in a vertical position hanging next to the oil pan.

I have seen a few cars where they screw in on a horizontal plane or even "upside down".

Here's the question. Does an anti drain back valve "do anything important" in a filter that is hanging down vertical next to the pan?

Isn't it going to stay pretty full of oil no matter what?

Thanks.

 

[Spitty]

quote:

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Originally posted by froggy47:
Most oil filters for the past 50 years or so mount in a vertical position hanging next to the oil pan

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Off hand I can only think of Domestic V8's that DO NOT have the filter Horizontal.

 

[Winston]

It is possible that the oil still could siphon out of the filter.

 

[T-Keith]

Nearly all of GM's products have vertical or near vertical filters. Most 4 cylinder's (except some Toyotas and VWs) have the filter at some angle.

Most FWD V6's are at a downward angle.


This has been discussed many times. Yes, there is a good amount of oil above the filter in the oil passages. Without an ADBV the oil can drain back out through the filter.

-T

 

[Triple_Se7en]

Quote:
Without an ADBV the oil can drain back out through the filter.


According to a nearby GM dealer, no filter oil loss occurs with any GM vertical-mounted filter that comes standard from the factory without an ADBV... ie... my Colorado 3.5L with AC PF-61. What's in the passages above the filter does not evacuate. I'm a witness to that - last time I changed the oil.... passages were full ... so was the used non-ADBV filter.

For the 4th time I will say this....

If you have a recent GM model with vertical filtering system that came factory-filled without an ADBV system.... you don't need any stinkin' ADBV. No need to buy the AC Delco PF-59... use the factory-installed non ADBV PF-61.

[ May 11, 2005, 03:07 PM: Message edited by: Triple_Se7en ]

 

[froggy47]

Thanks guys,

Spitty, ck my sig. I guess I need to "broaden" my taste in vehicles

All I've got is filters hanging straight down

Does oil run uphill?

I guess it could siphon out but I wonder if that's just a theory or has it been proven?

I'm just trying for a reality check here on whether an anti siphon valve makes any dif at all to my cars?

I don't think so but I'm open to a logical reason/argument.

 

[Winston]

To really know you would have to look at where the oil passages are in an engine compared to where the filter is. If there are passages above the filter the ADBV would help keep them full. One thing for sure. Just because the filter is verticle does not mean the ADBV valve is not necessary.

Even Triple's dealer qualified his statement with "GM cars that come from the factory without an ADBV." Not just all GM cars with verticle filters.

 

[y_p_w]

I've seen GM filters that were equivalent in every way except for the ADBV. The AC PF51 didn't have one while the nearly identical AC PF52 did.

I have heard that sometimes ADBVs aren't all that effective at keeping oil primed in the filter (overnight or longer) in the first place. What I have heard is that they can serve as a "check valve" to keep the occasional operational backflow from shooting massive amounts of crud trapped in the filter back to the oil pump. I've even heard of references to the valve as an "anti-backflow valve".

I'm pretty sure you'll get a certain amount of backflow when the pump shuts off.