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Klifex Oil Filter Housing Anti-Drainback Valve

416 Views 16 Replies 4 Participants Last post by  325TI_Compact
I had on-going P0011 issues. At some point, I realized it was the anti-drainback valve allowing the OFH to drain, which in turn led to low oil pressure on startup to the VANOS. Symptoms were the red oil light stayed on for a few seconds on each start (like a normal car would, after an oil change) and freeze frame of the P0011 showed it triggered at or right after startup.

Normally, one would just change to a new housing and change it again, when it fails. I am cheap and decided to try the anti-drainback valve replacement. I bought mine off ebay, from the Ukraine, for $30 shipped. Yes, the same one that is at war with Russia, but it still arrived in 9 days. It comes with a new OFH gasket also.

No instructions come with it in the box, but ebay listing (and the link above) showed a picture of using pliers to pull out the old unit, then installing the new unit, after lapping the plunger to seal surface. You reuse the spring from the original drainback valve. It's a really tight fit, so I ended up drilling sections of the original valve, until the rest of the old valve fell out. Original valve, mangled, but out of the housing:

Here you can see the grooves that the stock plunger eventually grinds into the housing, which is one of several reasons why it was no longer functioning:

The other issue with the stock design is that the plunger is too short. The Klifex design has a longer plunger which goes into a guide hole, keeping the plunger from dropping back in off-axis, when oil pressure is absent. Additionally, the replacement has wider plunger fins to spread the abrasive force of the plunger, as well as a better sealing surface shape.

If I remember. I'll report back on how well it's holding up.
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It's inevitable in the design that I have. Maybe theres a newer design? The plunger is too short. You can see on the non-sealing part of the stock plunger that there's grooves worn from the spring binding on it, while it was off-axis.
Can you clarify if you mean the slots in the housing or the plastic? From my reading, I'd seen various depths of grooves in the housing. I assumed it was from varied amounts of wear.
The plastic fins can only touch the aluminum when the plug falls back, off axis. The new unit does not allow the plug to fall back in off axis. That's why it prevents grooving and leakage.

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One more benefit of the replacement design: the new plug is ABS or reinforced Polypropylene. The stock part is likely Polyamideimide (PAI). PAI is significantly harder and stronger than steel, let alone aluminum. It's used to replace bearings in modern transmissions.

The new plug won't damage the valve metal.
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