BobMax

Does the 4th Gen have an anti-drainback valve ? Is it in the filter itself ?

My wife started the '99 (19K miles) this afternoon and it sounded like there was no oil in it. I had her shut if off immediately. I checked the oil, there's plenty, last changed about 3500 miles ago with mobil 1 5w-30 & new filter. Once I was sure there was oil, I had her restart... the clatter was less , then it went away after 20 or 30 seconds. Seems like a drainback problem.

thoughts ?
Bob

Daniel B. Martin

Yes.

Yes.

When the engine is running the oil pump draws oil from the sump and sends it upward through passages called oil galleries to clean, cool, and lubricate all the internal moving parts of the engine. When the engine is turned off, gravity will cause the oil in the galleries to flow "backward" through the oil filter and return to the sump unless something prevents that. The anti-drainback valve is a one-way valve (a "check valve") which prevents this from happening.

If the filter has a leaky anti-drainback valve the galleries become empty when the engine is not running. When the engine is started it takes a few seconds for the oil pump to refill the galleries. During that refill time
the engine parts, especially the valves, make an unpleasant knocking, clicking, or clattering sound. This symptom is more noticeable after a long period of rest, 24 hours or more.

Oil filters made for use in an inverted or horizontal position have an anti-drainback valve. This is true for all brands of oil filters. The difference (if any) from one brand to another is the material used and the quality of manufacturer. Any individual filter might have a bad anti-drainback valve.

The filter media, bypass valve, and anti-drainback valve are all internal parts of the oil filter. Therefore an oil filter is a "blind item" because the user cannot judge the condition or quality by sight, sound, smell, taste, or touch. When buying a blind item we make purchase decisions based on "image" factors such as the influence of advertising and brand loyalties. Choosing a good filter is further complicated by the fact that the same product may be sold under several brand names. Filter brands A, B, and C may be identical except for the brand name and exterior color. Industry insiders will know about this but most consumers will not.

If your engine exhibits the symptoms of a bad anti-drainback valve you should replace the filter. You might try a different brand of filter but (as explained above) it might turn out to be an identical product. I personally do not believe in the inherent superiority of the factory part but respect the opinion of those who do.

BobMax

I'll change the filter... and the oil too. I'm not usually a "stick to the factory filter" kind of guy unless I'm under warranty. This time I made an exception and it looks like it was a mistake. Back to the factory for now - if I have to bring it to the dealer, I'd like to eliminate one possible source of discussion. I'll try to get the filter cut apart after removal to see if I can tell what went wrong before I post negative things about the manufacturer.

Thanks again,
Bob

NickStam

iTrader: (3)

I always use the factory filter and I get that clatter. I hate that sound.

BobMax

I'm used to a bit of clatter here in the cold weather or if the car has sat for a couple of days. This is really out of the ordinary.

This was the first run with synthetic and it looks pretty dirty afte ronly 3.5K miles. I wonder if it dislodged a lot of goo that got stuck in the filter and the valve.

Bob

Daniel B. Martin

Please do, and post the results on this forum. That will be instructive for all of us.

Russell W. Knize investigated the construction and filter media size of many brands of oil filters by cutting them open. You may read his findings at http://members.nbci.com/_XMCM/minimo...study-faq.html

Knize has a low opinion of Fram filters.

CandiMan

iTrader: (1)

Here's a independent testing of several different filter, most if not all filters have this anti-drain back valve. Just like any other type of equipment, a valve can fail also

http://www.mr2.com/TEXT/oil_filter_test.html