Re: Clacking Noise.....

[zm@mhcnet.att.com (Zafer Mehmood [209])]

> 
> A question about filters with drainback valves. What does this do to
> the oil level reading? I remember hearing someone say that it holds
> about 1/2 quart of oil in the passages. Wouldn't this make the level
> in the pan read low? Or would a non-valved filter make it read high?
> 

I think the drainback valve will and does have an effect (although
minor) on the oil level measured by the dipstick. I was the one who
estimated about a 1/3 to 1/2 quart of oil remaining in the passageways
above the filter. I think it may be closer to 1/3 rather than 1/2 quart
(I just did an oil change recently, so newer data:-)
In any event, the filter also holds another third of a quart or so.

Audi probably takes all this into account when they specify the filter,
fluid capacity and designed their diptick. I find that Audi's specs for oil
capacity are correct. In my car ('87 5KTQ), the capacity specified is
4.5 quarts with filter change if I remember correctly. If I add the
4.5 quarts and check the oil level, its usually high. But if I start
the car up and let the passageways fill up and shut the engine off
and let sit for a while and check, its just right (I fill the oil
filter with oil before installing it).

But if someone is using a turbo filter (with the valve) in a non-turbo
car, I don't think an extra 1/3 quart in the passageways is anything
to worry about. Its only if the crankcase level is so high that the
cranks hit the oil and foams it, do you need to worry.

So, here's my oft-repeated (by me) prescription for keeping the noisy
lifters at bay: Use the turbo filter (Audi, Mahle, Knecht, Mann, whatever)
and Mobil 1 synthetic oil, change it every 5K miles and hum along in
your Audi.


Zafer