Oil filter leak (massive)

[billytan]

Car is a 1972 911 2.4E which ran the previous 3 years without any problems. A 2.7RS Spec engine was installed about a year ago. For the third time in a row since, the oil filter developed a leak at the rubber seal. The first leak occurred after about 4000km, the second after about 1000km, and the most recent after only about 500 km. The first two oil filters were from the same batch purchased from a vendor in the USA. Thinking that that batch of oil filters were defective, the third was obtained from the workshop that I used. The oil filters all have the markings "LS128/Porsche/930.107.764.01/Made in USA". The oil filter housing was the same /unchanged with both engines. The last two leaks were massive leaks that I could hear while driving the car, with complete loss of oil pressure. Stopping and inspection showed massive leakage of oil from the filter mounting site. The rubber seal is buckled outwards and can be seen protruding from the rim of the oil filter. Has anyone experienced this before? Any ideas as to why this is happening? MAny thanks, Billy, SIngapore

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[cmcfaul]

There’s some kind of foam ring that goes around the filter hole when installing. I have had that get in the way of a proper seal (I think I removed it eventually). Also, if you don't lube the rubber ring on the filter when installing, it will bind and not seal correctly. Never used the Porsche filters, always the Molly as they have a pressure relief valve in them specifically designed for these cars.

My c Cents.

Chris
73 911 E

[T77911S]

what is your oil pressure? carefull when it is cold, if the bypass is not working, oil P can get over 100psi. does it look like the botom of the filter itself is distorted, like from too much pressure?

what does the surface look like where the filter screws on to. is there some old gasket left behind? my dad kept having problems with one of his cars. he found an old filter gasket stuck to the flange where the filter sealed.

fresh oil on the seal to lube it

[rfuerst911sc]

Just for the heck of it I would try a OC54 filter # 930-107-764-01M67 maybe you'll have better results. And make sure that an old oil filter gasket isn't stuck to the filter console. And last make sure you put clean oil on the new filter gasket before installing. Good luck.

[Eagledriver]

Your oil filter is experiencing very high oil pressures. I've only seen this at the track on a cold day, the driver reved the motor to high before the oil had warmed up. I doubt this is your problem if you live in Singapore.

Your indicated oil pressure in the car will not tell you anything about the oil pressure in the filter. They are on separate oil circuits. The filter consol in your car has a pressure relief valve in it that is supposed to prevent this. There is also a thermostat there if you have a front oil cooler. Is you oil cooler system stock for your car? If you have an aftermarket system or a malfunction in relief valve you might have a pinched oil line to your front cooler. Somewhere there is a restriction between the oil filter and the oil tank.

-Andy

[john walker's workshop]

the end of the filter is all rounded out. too high rpm on a freezing day maybe? the cooler pops from the same thing.

[billytan]

Dear All, Many thanks for the replies and the leads.
1. Am in SIngapore so environmental temperatures are about 28-32 degrees Celcius.
2.The mounting surface on the vehicle side is clean, aluminium I think.
3.The cars runs an external oil cooler mounted beneath the front right fender. The fan to this cooler is manually activated.
4.The last 2 occassions of a massive leak both developed at start-up with revs maybe reaching 2500 rpm?
5.Where is the "By Pass" and how do I check it? (T77911S)
6. How do I check the relief valve in the Filter Console? (EagleDriver)
7. What is the "Molly" filter. Have heard of the OC54.

All 3 times the filters and oil change were professionally done at a workshop very familiar with servicing and repairs of Porsches.

Many thanks again. I must sort this out or I would not dare go on long breakfast drives into neighbouring Malaysia again.
Wishing all a good weekend ahead. I know how mine will be spent . Billy, SIngapore

[Formerly Steve Wilkinson]

The only part I can answer is that the "Molly filter"--why can't people spell???--is the Mahle filter, a standard 911 fitment.

Oh, and don't go into Malaysia. You might meet someone who'd been arrested in Singapore for chewing gum.

[Eagledriver]

There is a blockage somewhere between the filter and the oil tank. You might inspect the line leading from the filter console to the oil tank. It is in the right rear wheel well and is routed along the top of the wheel well and into the oil tank at the top of the tank. Perhaps this line is very old and has swollen inside to the point where it won't flow the oil anymore.

I don't know how to inspect the pressure relief in the filter console. There is a plug on the console that can be removed but I think that is for the thermostat.

-Andy

[billytan]

UPDATE:
FILTER CONSOLE
The filter console was removed and cleaned. Mounting surface for the oil filter is nice, flat and clean. No thermostat (blanked off) which means that oil flows to the front oil cooler all the time, so that will not cause a build up of pressure when starting from cold. The relieve valve piston and spring present and not stuck.
OIL LINES TO FRONT COOLER replaced by brand new ones, fabricated according to the oild lines. No valves found in the line, so they are open and through flow all the time.
FRONT OIL COOLER removed, cleaned, flushed through, good flow noted.
OIL TANK- Cleaned and replaced.
PORSCHE Brand filter replaced - became bloated after a few days use.
MAHLE Brand filter replaced - became bloated after a few days use (less than 100 km)
With ALL the components beyond the oil filter either being new or completely cleaned with no blockage ensured, my mechanic and I reasoned that the block MUST be at the filter console, and most likely at the RELIEF VALVE. Possibly at some time a different rated spring was installed so that the relief valve does not open/open enough when the pressure builds up at high revs to bypass the filter.
1. Any information as to the correct spring specification to be used for the relief valve?
2. Any vendor that still sells it?
3. Is it the same for a 911E (my car originally) and a 2.7RS Spec engine as is now in the car?

Whats perplexing is that for 3 years when the car was running with the 2.4E Engine, this problem did not occur. The fuel filter console and the front oil cooler set up was the same (unchanged) for both engines.

Any other possibilities? Many thanks and HAppy New Year to everyone. Regards, Billy, SIngapore

[T77911S]

cold high pressure oil to the front oil cooler can blow it. i would put the Tstat back in, plus it will help with warm up. mine barely gets to temp by the time i get to work if it is cold out, and that os a 20-25 minute drive.

the oil filter is on the scavenge side. i have no idea what kind of pressures are there. if there is a blockage, it would have to be after the filter to cause pressure in the filter, if so, i would be concerned about oil starvation.
if the pressure relief opens, would the pressure feed back to the filter? with heavy weight oil and a cold morning will it send that high pressure back to the filter?
the pressure relief is in the engine, also, maybe the new, or different engine has much higher OP, especially cold.

[Turboo934]

Not having the "THERMOSTAT" on the front oil cooler lines will cause this, can also rupture oil cooler. Porsche puts them there for a reason.

[billytan]

1. Early morning temperature in SIngapore never gets lower than 26-28 degrees C.
2. The oil used is fully synthetic 10-50W
3.The oil is pumped through the primary oil cooler, into the oil filter console, into the oil filter, onto the tube that brings it to the front oil cooler, and then back to the oil tank (where in a 1972 car the oil filler cap and dipstick are located, and then back into the engine crankcase.
4. The themostat (as I understood it) is to close the flow to the front oil cooler until the engine is warm enough to need more cooling, whereby the valve opens to allow flow of oil to the secondary oil cooler in front. When opened ALL the time (being without a thermostat to close/open the valve) pressure within the oil filter system should be lower.
5. The relief valve in the filter housing actually opens when the pressure within the oil filter is too high, and it allows some oil to BYPASS the filter and proceed straight to the front oil cooler

WHich is why I suspect this relieve valve is not opening or not opening enough when the pressure builds up, so all the oil pumped by the oil pump in the engine is forced INTO the oil filter and causing it to expand and subsequently pop.

Thanks again for the help. Billy

[GeorgeK]

That filter is swollen, badly. It has seen HUGE pressure, and not the kind you'd see under any rpm/temperature conditions. There is an anomaly in your setup that causes this. Engine, lines, thermostat, filter.
I would look for a blockage in *all* th oil lines, before something gets damaged.

[Grady Clay]

billytan,

First, the oil filter WILL see way too high pressure if all the cold oil is forced to the front cooler. Anything colder than 220F is too cold.

Are there three 25 mm hoses on the back (outboard) side of the oil filter console? If not, the pressure relief valve in the console is non-functioning. Even with the thermostat and 3rd hose, the relief valve has to operate under some driving conditions at operating temperature.

Compare what you have to the below diagrams and report back any omissions or discrepancies.

Is there any sign of ‘swelling’ of the front cooler? What type is it? There were some Factory defective Carrera cooler where the oil could pass from one side of the ‘top tank’ to the other side and little through the cooler tubes to and from the ‘bottom tank’. If you have one of these, it may be saving the cooler from failure but not cooling the oil properly.



backdate oil system to '72...

Originally Posted by Grady Clay

Keith,

As I said last week, I think I have some good illustrations
somewhere. Of course they might be in the stuff I gave away
almost 20 years ago and it only seems like yesterday.

The biggest issue is you are now committed to a ’72 only system.
Do it right.
IMAGE OilCircuit72Sa
"
"
© 9/1972 Dr. Ing. h.c. F. Porsche A.G.

IMAGE OilCircuit72Sb
"
"
© 9/1972 Dr. Ing. h.c. F. Porsche A.G.
I have these images as big (7.0M) files if you want. Just e-mail
me at gradyclay@hotmail.com

In the two illustrations they show two different oil tanks, #19
and #51 but they are actually the same tank 911.207.010.00.
The only other tank is for the Sportomatic 911.207.021.00. I
wonder if the Sportomatic tank was larger in addition to having
the two fittings for the torque converter hoses. Anyone know?

You are going to need to replace your oil filter console #8
(916.107.028.01) with #57 (916.107.028.00) that has three oil
fittings on the outboard side. It is possible to machine the #8 to
accept the thermostat (#58) and 3rd fitting (no number). Some
even came with block-off plates (#13) and plugs (no number).

I used to have some kits “for subsequent installation” that
included all the pipes, hoses and hardware but they are long
gone.

Elephant should be able to help you with the pieces to and from
the front cooler. I would use the ’87 Carrera cooler because it is
very robust, has metric fittings and accepts the Porsche fan.
There are good aftermarket coolers with AN fittings also. You
could use the pipes and front hoses from an SC or Carrera but
you will need to modify them at the rear to adapt to the ’72
configuration. One needs to be like #63 & #64 and the other to
be like #59 & #60.

Don’t use an original ’72 only cooler (#65). It is way too fragile
and any few should be for serious show cars.


Chuck, have you ever investigated Argus as a source? They were
the original manufacturer of much of the oil hoses, particularly for
the race cars. I used to have a supply of bulk metal braded
hose, aluminum fittings and the installation tools. They are now
a division of some large conglomerate – in the Netherlands I think.

Best,
Grady

Originally Posted by Grady Clay

Here is another diagram.
I know I have some with the internal plumbing of the oil filter console.

IMAGE OilCircuit72Sc.jpg
"
"
(C) Dr. Ing. h.c. F. Porsche A.G.

Best,
Grady

I hope this helps solve the problem.



As an aside, in ’73 Porsche went to the ‘trombone’ cooler and deleted the pressure relief valve without announcing the change. In order to improve the oil cooling at our altitude, we replaced the trombone with the ‘72S cooler on all the new cars and ones we serviced. All the coolers failed or swelled when the weather cooled in September.

We immediately changed to the ’74 and later thermostat and relief valve common through 911SC and 911 Carrera.

Best,
Grady

[billytan]

Thanks to all for the help. I emailed Grady with a few more questions and am very thankful for a very detailed reply, appended below:

GRADY CLAY:

"The problem is that you don’t have the 3rd hose on the oil filter console assembly.

That hose is probably the one re-routed to the front cooler and it should take oil from the low-pressure side of the pressure relief valve and return it to the oil tank. Additionally all the cold oil should be returned directly to the oil tank via this hose.

In your case, all the oil is passed through the front cooler before returning to the oil tank. Not good and the cause of this problem. I think the way it is plumbed, the oil pressure relief valve only sees the pressure differential across the oil filter and does not protect the filter and cooler from overpressure.

Did you install the front cooler with the 2.7RS? If so, your system had the original hose from the oil filter console to the top of the oil tank. Whoever did the conversion directed that hose to the front cooler causing this problem.

The thermostat is the same part as the engine thermostat – you end up with two: one on the engine and one in the oil filter console.

Your oil filter console should have two openings blocked off: one with a cover plate where the thermostat goes and a plug where a fitting for the 3rd oil hose goes. The plug is replaced with a threaded fitting, same as the other two. That fitting is not listed with a part number. However, it is the same as the fitting where the oil is pumped out of the crankcase on 3.0 and later engines.

Your oil tank should have another opening (threaded fitting for a 25 mm hose) blocked off. I suspect it is the one on the bottom of the tank that should be the return from the front cooler.

The correct plumbing is a hose from the oil filter console to the top of the oil tank. This is a common hose for both use without a front cooler and with the front cooler. I suspect this hose was re-routed to the front cooler but this is the correct port to go to the top of the oil tank.

The new ‘3rd hose’ from the oil filter console goes directly to the front cooler. This hose assembly is unique to systems with the front cooler.

The return from the front cooler goes to the threaded fitting (now blocked off) on the bottom of the oil tank.

The oil circuit diagram that Harry posted is for 1974 and later and not indicative of your 1972-only system.

While you have your front cooler out, take a light on the end of a wand down one port and see if you can see light in the other port. There is a flaw there the two sides of the top of the cooler were not totally sealed from each other. A bore scope is even better. "

I have found the opening at the bottom of the oil tank,the third opening on the filter console that is regulated by the thermostat and the opening for the thermostat itself. So will be setting the circuit right. This front oil cooler was installed by a previous owner. It is just weird that it is giving this trouble only now. Thanks again to everyone and Happy New Year.

PS: When all is done and the oil filter remains in correct shape, I will post the good news.

[dshepp806]

Are we fortunate or what?

......good stuff, Grady.

[HarryD]

Billy,

I hope you get your problem solved. I deleted my post with the incorrect flow diagram to prevent confusion to others.

[billytan]

Many thanks to all for advice given on this matter. A big thank you especially to Grady Clay for the detailed instructions on what to do. IT'S DONE AND IT WORKED. The filter remained in nice original shape despite the hard driving I have subjected the car to. Much appreciated. This is a great forum, great help. Warm regards, Billy.