Low oil pressure solved! Don't use Mann & Mahle oil filters

[reluctantartist]

After a long period of time trying to determine if my oil pressure gauge was really way off (it isn't super accurate but it is close enough). Cleaning the relief valve up and making a tool to resurface to face in it. And finally coming to the conclusion the oil pump must be on its way out since my engine didn't need oil between changes. I came across talk of the quality of mann and mahle oil filters in a Porsche site. Mann and Mahle oil filters are all I have ever used since everyone said you can't go wrong with them. Well they were wrong, these filters were causing my problems. When I changed the oil, I installed a Wix oil filter (make sure you get the more expensive one at the flaps if there is a choice) and my oil pressure problems were solved and my oil pump is working quite well. I hope that using quality oil limited the extra wear caused by the lower oil pressure. My running pressure when it is warm 180+ is now 35-40 at 3100 - 3200 rpms (this is an estimation since my gauge can be off when it is going up it seems to be 5+ psi off), with a mann or mahle filter my pressure would be 25-28 psi and if it was over 180 it would drop to 20-25. My idle when hot is now over 15psi verses 7-10psi. I would tell anyone to use a Wix filter instead of a mann or mahle there maybe a few others but I only have experience with Wix.

[dtrumbo]

I'll second that emotion. I only use Wix and are very happy with them. NAPA sells them as their NAPA 'Gold' filter. Wix 51521 or NAPA Gold 1521 for your Type 4 buses.

[Amskeptic]

I'll second that emotion. I only use Wix and are very happy with them. NAPA sells them as their NAPA 'Gold' filter. Wix 51521 or NAPA Gold 1521 for your Type 4 buses.

NAPA Gold 1521 . . . don't leave home without one.
Colin
(about halfway down the first page)
viewtopic.php?f=46&t=394

[vdubyah73]

any body have an opinion about a bosch 3402?

been using them for about 6 years now. no complaints. no gauge. i can't swear by it, but i can't remember my oil light flickering after hours of freeway flying. we're talking going 70-75 mph with some 80 mph when traffic is moving that fast. have made many 500 mile day trips to nyc. usually just pick up or drop off, turn around and drive back, have 2 single daughters down there.

[poptop tom]

I used the NAPA Gold when I first fired the rebuild up, and have since been using the Mahle.

I have noticed the same thing with my oil pressure. When I change to my summer oil, I will
be switching back to the NAPA Gold.

[reluctantartist]

My only concern now is how much damage to the engine occurred from using the Mann/Mahle oil filters? Another thought, if I did not have a pressure gauge I would still be using them. since the factory oil light would never alerted me to the oil pressure situation.

[Amskeptic]

My only concern now is how much damage to the engine occurred from using the Mann/Mahle oil filters? Another thought, if I did not have a pressure gauge I would still be using them. since the factory oil light would never alerted me to the oil pressure situation.

Don't even worry about it. If your engine is holding pressure right now it is because everything is in spec.
Colin
( is Hippie here? ever heard of an oil filter damming back oil pressure? if a pump can put out, it is going to put out. a "clogged" or "restricted filter" with a good pump is merely going to open the bypass valve)

[Hippie]

( is Hippie here? ever heard of an oil filter damming back oil pressure? if a pump can put out, it is going to put out. a "clogged" or "restricted filter" with a good pump is merely going to open the bypass valve)

The bypass will drop whatever it's spring pressure dictates like a regulator, and if it's sludged up, it will drop even more.
Still it's odd. Maybe the Mann-Mahle filters are cheapening out on the media surface area. I've never heard of problems with them on a stock T4 until now. The Wix has its own bypass in most models, so then you have two in parallel, the filter's and the bus'. That can't be a bad thing.

@dubya73, that particular Bosch filter is a PureOne painted black, and my only gripe is that its bypass valve is at the wrong end...the domed end. When you drive it cold, or rev it up hot, the bypass opens right next to the bits of sh!t that have collected at the bottom after having been strained out by the paper. They can get sucked back into the oil going to the bearings.


-Rob

[reluctantartist]

poptop tom please let us know what happens for you when you change out the oil filter to a Wix.

Also in my searches the 20-25 lbs oil pressure when hot seemed to happen enough to not be unique. Everyone blamed it on the oil pump, gauge, or bearings and never seemed to solve it or never reported back after they planned on doing a chnge. Some even replaced the pump with a high-flow pump but then had high oil temp problems. Also I do not know how common it is for people to have an oil pressure gauge so maybe this is occurring more often than not. It sure is a joy to drive now when I look down at the gauge and see it showing more pressure than before. My oil temps have not changed much, maybe they are a little cooler than before but I can't really verify that yet.