Redd

I'm new to Rennlist.... I've tried to search the forums for this issue, but no luck.
I recently had an oil change done on my 1998 993 (manual)
The used filters coming off the car were Porsche brand name filters.
The new replacement filters my mechanic used were Mahle brand name filters.


Once the old filters were off the car, I examined them visually to see if there were differences between the two brand names. I have heard that Mahle makes the filters that are branded Porsche (correct me if I'm wrong).
Obviously all I could do is compare them without disassembling them, so this was only an external comparison and looking inside through the holes.
No obvious difference on the small filter.
However, on the larger filter, there appeared to be a check valve mechanism near the hole on the Mahle filter. The old Prosche brand filter coming off the car did not have this valve mechanism.


The mechanic was a bit apprehensive about installing the filter with this difference in mind, but since no replacement was readily available so we installed it anyway. He said I should carefully monitor the oil guages and oil level on the dip stick for the next few kms.
Now comes the odd behaviour of the gauges:
Dip stick level is good (engine running and warm).
Oil pressure good and high.
Oil temp is normal (about 09:00 position)
Oil level is at the very bottom (empty position) !


Driving around a bit had the oil level gauge move to about half full position for a few minutes, then needle falls back to empty position.
This erratic behaviour of oil level guage still continues after roughly 300 km of driving .
These observations are always with the engine warmed up.
This situation was not happening before the oil change.
Oil level on the dip stick is still within range of twist in the stick.
Could the check valve in the Mahle filter have something to do with the oil level guage reading?
Anyone have this experience before?
Thanks

User 122821

Strange that you mention this. Originally I've always used Mahle oil filters on several 911s (73 911s, 88 Carrera, 930) I've owned. Never a problem with the oil gauge. My gauge on the 993 was always off compared to the dipstick. I figured I would pull the oil tank at some point to see if it was sticking. For the last two oil changes on the 993 I've switched to Porsche brand since my new part source has them for a couple of dollars more than a Mahle. As of switching to Porsche brand filters, the gauge matches the dipstick on the 993.

Not sure why, but there you go.

pp000830

Oil filter brand is a non-issue here. Just make sure you change them and your oil regularly. Some oil filters have a valve useful for installations where the oil filter is installed in such a way that it tends to drain out when the engine is off. Likely not an issue with the filters in a 993 due to their location, orientation and position in the oil path related to the oil tank.

If others have better insight please comment.
Andy

chsu74

Matters on a 993TT. Must stay with Porsche Filters

Quadcammer

he's talking about the large filter...which is unusual.

Mike J

Do a search - the physical difference between the filters was a topic a while ago, and various filters were cut apart and compared. The construction of the Porsche branded filters is different especially with the check valve design, which is essential for TT. I do not have the reference on that thread, but it's around.

I only use Porsche filters on any of the Porsches I work on - period. If someone supplies a non-Porsche filter, that is their call. I ONLY use Porsche filters on my 993TT.

This is not a place to save a few bucks.

As far as impact to the oil level gauge, have no clue since I do not use Mahle.

Cheers,

Mike

Redd

Thanks for your feedback guys.
I will order the Porsche filters for my next oil change and see if there is a change in the gauge behavior.
In the mean time, I will be regularly checking the dip stick!
Bruno

FrannyB

Hi Redd,

Checking the oil on these cars is a bit tricky. I don't know if you are new to these 993s, but it is essentially the same for the 3.2 Carreras - The engine has to be warm as you have noted, but then the car has to be idling (and stationary) on a level surface for a couple-few minutes to get a proper reading from the dash. The oil in and out of the tank has to stabilize first. Always makes it fun at oil changes in that you can really check the level until the car is hot.

Anyway, maybe that is why you are seeing the level move around a bit. I usually check it when I'm back from a run, in the garage (reasonably level; driveway is not) and just let it idle for a few or until the needle stops moving.

Makes me wonder if this wasn't a consideration for the very different 996 engine design...

Franny

Redd

Franny,
The way you described how to check your oil level happens to be exactly how I do it also.
Drive it into the garage after a spin and let it idle while I check the oil.
I guess the dip stick is the only sure way......but still a bit unnerving to see the gauge at empty sometimes.

_snowbird_

My oil gauge is always at empty while driving. Then when warm, level, and idling the gauge raises to just around the top of the solid line on the gauge.

Start driving again, and the gauge drops back to empty.

I think I have Porsche oil filters, but am now curious.

TJ993

The Oil level always bounces around when the car is driven. That is Normal.

When u come to a stop if on level ground, the level indicator will rise, hopefully above the red area on the gauge.
I know it is Un-Nerving.

BUT As u already stated, the safest way to check oil is after a heat cycle - or a good run. Then get the car on Level Ground AND then Use the dipstick.

Oil filters - My Mechanic said due to occasional Porsche Filter failures BUY MAHLE OIL FILTER # OC 229 and OC 213"

He said to ensure the Mahle Filter I buy is "MADE IN AUSTRIA"

Now in my 4 years of ownership I have had Zero issues with the Porsche Filter - So his experience may have been a Decade ago>
I buy Mahle And. I get the mahle on Ebay

KNS

Perhaps an isolated occurrence but my small Porsche branded filter just started leaking after about 2000 miles. I installed it hand tight and it was still quite tight when I went to remove it. No other oil in the area or from above the area. It was leaking from where the seal mates up to the filter console. Replaced it with a Mahle filter and so far so good.

I've always used Mahle filters on 911s before I owned the 993 and never had any issues. I'll monitor this and see what happens but I think after reading the ECS comparison I'll be sticking with Mahle filters.

NoRush993/951

An article on 6Speed in the 993 section had photos of the two filters cut apart and the Porsche branded filter had the check valve to prevent oil backflow and the Mahle filter did not. I switched back to the Porsche branded filters and haven't had any blue smoke on start up since.

myflat6

Very interesting. Thanks for sharing. I wonder if the same is true for filters for earlier cars?

Redd

This is funny.... I just bought Porsche filters from the dealer (made in USA) and they do not have a valve inside.
As soon as I do my next oil change, I will post pictures of the large Mahle filter I remove from my car (which has a valve), to compare with the Porsche branded one.