Sonata oil filter

It lets the oil "above" the filter in the engine passages drain back into the filter and crankcase. True, the filter likely don't drain, but it isn't impossible even with a vertical filter. You are familiar with the principle called siphoning, right?

An anti-drainback valve is an essential part of a filter and I wouldn't use a filter that lacked one or had an ineffective one (Fram).

Matt

Yep, Matt, I thought about the siphoning action but doubt that it would be a problem. For years, as I said, the valve is a bypass valve, not an anti-siphon valve. I can see that, in cold weather when the oil is more viscous, the oil flow to the valve gallery would be reduced allowing the lifters to not pump up fast enough and cause some clacking. That would be more reasonable. The fact that the OEM Bosch filter doesn't have the valve (at least in a visible location) is puzzling. I will be writing to Bosch to let them know and get their input.

Tom

I just went on the Bosch site and they say that their Premium Filters have a silicone anti-drain back valve, so it must be in there somewhere. I just can't see it.

Tom

The mystery is solved! The key was 'silicone' valve. In my years working for packaging companies, we had silicone vacuum or pressure release silicone valves, which were nothing more than a little silicone flap that covered a hole. Well, I looked at my spare Bosch filters and, there it was, a silicone gasket that was just below the holes around the periphery of the filter. The oil is forced through these holes and, in the process, push the silicone gasket away from the hole. The oil goes through the filter and out the center hole back to the engine. When the oil tries to come back through the filter down the center hole when you shut off the engine, it pushes the silicone gasket against the holes and prevents reverse flow.

Thanks for pushing me to a solution, Matt. I guess it's never too late to learn. :o)

Tom

I'm not sure I follow you. A good filter has both a bypass valve and an anti-drainback valve. They are different animals that serve different functions.

Matt

Need a fuel pump, starter solinoid and a good master cylinder for my 1931 a ford also could use a radiator for my 1966 V.W. bug.

A radiator for a '66 Bug? That must be a customized 1300 machine, 'cause all of mine were air cooled...the '59, 66, and 71SB...

Can't help you with the Ford, but then again, it's a Ford.

Just Kidding!

Taters, I have a BRAND NEW in the BOX radiator for your bug, also have BRAND heater core also, make me a DECENT offer for both.

']['unes

I knew that. If I thought you were serious, I would have tried to sell you some!

Crap - it looks like ']['unez beat me to it...