Oil filter, drain back issue.
 

Have been having some oil filter issues which I will try and explain below.

I had a Black Subaru oil filter which I had no problems with but needed an oil change.

I fitted a Blue Subaru oil filter and did my normal oil change.

All was well initially until after a few miles under the belt. It started as taking a bit longer for the oil light to go off.
Usually with the black oil filter would take 1-2 seconds if that, and after not being used for a week would take 2-3 seconds with the cam sensor off to go off.
The Blue filter after an hours driving and stop it would take 3-4 seconds to go off, and after a week (same as above) would take 7-8 seconds to go out. And was getting a bit worse, as time was going by.

This made me a bit concerned, as I thought it could be the oil pump on its way.

And then I saw the thread on here from the NASIOC, which got me thinking it could be just the filter.

So went to my local motor and they didn`t have a Blueprint filter and I had already looked for a black one with no luck, so bought a MANN filter as a short term measure.

Anyways fitted the Mann filter, and its back to how it was with the Black Subaru filter.


So I decided to open the filters to have look at whats what.

The blue filter is utter crap, the rubber "seal" wasn`t sealing and the filter was rattling inside, it was if the spring wasn`t working. But even if it was the rubber seal inside didn`t fit the cardboard. The Black sprang apart when opened, and the seal was a LOT better, and weighs a lot.

Anyways heres some pics.

Attachment 67408

Attachment 67409

Attachment 67410

Attachment 67411

Attachment 67412

Attachment 67413

Attachment 67414

Filter on the left is the Blue Subaru filter and has been in few hundred miles.
Filter on the right is the Black Subaru Filter an has been in for 6 months ad a few thousand miles.


Your thoughts.

OK I conceed the Blue filters are crap (well compared to black ones).

However, that looks a dark blue, I swear there were blue ones that were a lighter blue colour than that and had less holes in the top? The genuine blue ones I had before never said Honeywell on them - thats for certain, so maybe there are different types of blue filter out there?

Just as well I usually used Crossland and Unipart filters in my scoob. :D

I don`t know about colour, but it seems to match the filter in the NASIOC thread about Honeywell (FRAM) filters.

In the Subaru application the drain back seal is superfluous. As the unit hangs vertically down, the oil cannot drain from the filter.

JohnD

No but the oil above the oil pump can flow down as there is no seal to stop it. Just because it faces down doesn`t mean it cannot drain above. Also due to no seal the pick up pipe can drain also, where if the seal was working it would remain full as long as the pick up remained in the oil, only draining very slowly after a while.

If its superfluous, why did I have the issue with the filter that had a rubbish drain back seal??

I use UFI filters from Opie Oils and Purolator prior to that and neither have the drain back diaphram. Oil pressure is instantaneous even after sitting for a week or more.
The filters, like many others , are not exclusive to Subaru, in other applications they may well require an anti-drain back facility.


JohnD

Have you taken one apart to see? As the oil above the level of the filter without some form of seal will flow to the lowest collection point, so into the filter and then into the sump. The filter will retain some oil inside.

If you have a one way valve inbetween (seal) then the oil above the filter won`t be able to flow, also the oil in the pick up pipe will remain also.


The easy way to demonstrate it is to suck water into a straw, then pinch the top so sealing it, the water/coke/liquid stays up in the straw, if you remove the seal the fluid drains. This is what the seal in the filter does afaik.

I see what you are saying but in the case of a filter without the seal, would the mass of oil above the filter in the outlet side (centre of filter) overcome the mass above the filter on the inlet side (pump to filter) A bit like the water trap under the sink!
It would be interesting to hear the thoughts of the engine builders who frequent these forums?
I certainly don't use these filters because of their lack of rubber valve it's just that is how they're supplied.

JohnD

Yeah I agree.
I didn`t think it mattered until I had this blue filter, its strange. Its only when I had it on the oil light took longer to go off and was taking longer and longer. To the point I thought something was up mechanically, when I swapped the filter to a different one it stopped, and I did the same procedure in filling the filter and priming both times.
It was only when I took apart the filters did I find the "difference", I don`t know why they made a difference, all I can do is try and explain what I think happened from the bits infront of me.

I've started another thread calling for engine builder comments on the anti drain-back valve question.

JohnD

Maybe just a dodgy filter?? . As you say , the oil will flow to the lowest point (filter/sump) But that is normal for any car , as when it sits for a while the oil will naturally drain from the top end to the bottom , but that is why a certain amount of oil is in the car to start with , e.g filter and sump at proper level which is enough for the pump to push through the rest of the engine.

This has me interested now as to what filters are good and bad, I have never gave it much thought.

My car has a Blueprint filter on it as the last owner changed the oil and filter just before I bought it last month.

Is the pink STI one better than the Black subaru one then ???

I believe the Blueprint items are quite favoured? I'm about to pop out and get a couple (plus a new fuel filter) from a supplier here in Romford.

JohnD

That's good to here John thank's.

My car had a full engine rebuild done not long ago and for the price of a oil filter you want the best to keep the engine as good as can be..

Blueprint oil filter (ADM52106) £4.03 fuel filter(ADM72305) £19.32

JohnD

My main issue with the blue filter pictured above is the quality of the filter media itself.

The endcaps are nasty - I've used non OEM cartridge filters in BMWS with paper/fabirc end caps as opposed to OEM quality plastic and found they had a nasty habit of tearing where it glued to the filter media. There appears to be more holes in the inner tubing insert which will allow for oil to be evenly distributed through more surface area of the filter media, the pleats of the filter media also appear to be deeper which equates to more filtration surface area too.

I suspect the start-up issues is not the drain back, but actually the flow rate through the filter media itself. OR the bypass valve (not pictured) is faulty or insuffient. This would allow thick (cold/cool) oil to bypass the filter and prime the engine faster.

A weak/sticky PRV in the oil pump (or loose/leaky back cover) or large bearing clearances could exasperate the issue making the engine more sensitive to suffering issues such as this.

I must agree the blue filters look crap, when compared to the black ones, so much so that at my last oil change i was going to fit the blue one, i had purchased as a spare, but ended up fitting a black one i had in my garage.

The blue one i bought from a subaru dealer, did not come in a box just shrink wrap, made in canada, would be nice to get some feedback from some engine builders.

Have you gone off UFI Filters then :confused:

Ha,ha - No not really, it's just that I'd used my last one at an oil change so I thought I'd give the Blueprint a try as there's a stockist in town.
I usually get a couple of filters at the same time as getting oil from Opie but at the mo. I have enough oil but ran out of filters!

JohnD