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Subject:Re: knocking noise
From:Ben McCafferty
Date:Wed, 6 Mar 2002 14:04:05 -0800

> A more likely cause is your oil filter, but it could certainly be sticky
> lifters.  With cheapo filters like the ones you get at your FLAPS, the oil
> can drain out of the filter and back into your pan.  When the engine first
> starts after sitting for a longish period of time, the oil filter has to
> fill up first, then your lifters get pressurized.  (This is at least how I
> understand it)

While the oil filter bit is certainly valid for oil pressure, I have never
understood how oil could drain out of a filter that's not laying on its
side.  Are the older WBX filters horizontal?  On my old 89 and my current
90, they sit at a 45 degree angle, and you'd have to turn the van almost
onto its right side to get the oil to drain out of it.  Incidentally, I
don't believe the Mann has a flap that keeps oil in it either, and it will
drain if it's laying on its side.  Try it with an old one some time.

Even with oil in the filter, the lifters make noise from time to time.  I
don't know for sure, but my theory is that it depends on how the engine
stops, i.e. if there's contact between lifter and pushrod, to keep the oil
in there, or if the hole is covered.  But I can say with certainty that with
a Mann filter full of oil, I get lifter noise as well.  Every Vanagon garage
I have ever asked about this has said it's a very common thing with WBXs and
nothing to be overly concerned about unless it doesn't go away after a bit
of driving.
>
> I'll bet the car does this after sitting for a few days, right?  Try
> switching to a Mahle or Mann filter and 20-50w oil in the summer and I'll
> bet the problem gets better/goes away.
>

I use the Mann filter, Castro 20W50, and I still get an oil pressure
light/buzzer from time to time.  Some WBX engines have marginally low oil
pressure, and the filter doesn't solve that, though it *may* help.

bmc  :)