Re: That's a very typical oil leak ....

Hi guys, I did a lot of research on this before I recently purchased a 2002 C4S tiptronic. While I never planned on purchasing a tiptronic 911, once I weighed up the chances of getting a manual which may have worn syncro's and the fact that quite a lot of people seem to point to a lower IMS failure rate on a tiptronic cars I decided to go for a tiptronic car.

Not disapointed at all, the perfomance is great and as I only drive short journeys during the week I am happy with my purchase.

This weekend the car had it's annual MOT (UK road worthy check) and as I know the guys well I took the opertunity to take a look underneith while the car was in the air. Oh dear! There appears to be some oil where the engine meets the gearbox. Dare it be the RMS and should I be panicking?

I have attached some pictures for peoples opinions. I am not going to panic, the car hasn't lost much oil and doesn't appear to be leaking on the ground.

Look forward to your opinions.

Sorry pictures here [s1148.photobucket.com]

... most likely from the RMS.
If you don't have a puddle of oil on your garage floor and can live with it, it's nothing to panic about.
If it gets too bad you may want to consider getting it fixed because oil on the dual mass flywheel will eventually damage it.
Happy Porscheing,
Pedro

BTW , Welcome to the board, Sel

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Pedro,

The car has a Tiptronic transmission. In a 996, can the Tiptronic transmission be pulled separately? Or, does the entire engine/transmission package have to be pulled?

Bill

.... sometimes it's easier to drop the whole package on a 996 and then work with it on the ground.
The equivalent of the front engine mount is at the front of the tranny and the two motor mounts are at the back on the 996.
Happy Porscheing
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

that appears to have been washed clean by oil running down. For this to happen means the source of the oil is above the RMS.

You or someone needs to get car in the air (safely) and with the engine/exhaust cold and the engine off feel about looking for where the oil is coming from.

It you find I'm right and the oil is coming from above the RMS, then the oil can be from a leaking spark plug tube, a camshaft cover, or an AOS.

Sincerely,

MarcW.

Thanks for the replies guys.

Pedro, if I do go ahead and get it looked at would you recommend fitting the retrofit IMS bearing at the same time or just to inspect it and possibly change the IMS seal? I don't think it's leaking too bad at the minute but I will be monitoring like a Hawk from now.

Marc it's interesting where you say it may be oil from above the RMS and that's got me thinking. When the RMS seal leaks would oil come out from the bottom of the join where the gearbox and engine meet or could it come out from above?

And just thinking out loud here, but as this is the centre of the engine wouldn't spark plug leaks be on the outside edges of the engine as opposed to the centre of the engine? Not sure what the AOS looks like. In fact before just Goggling it I didn't even know what an AOS it was

I was thinking about cleaning the area and then looking to see if I can see where the oil comes from after that. Does that sound like a good idea or do you think that may wash away the evidence and if I look properly as it is currently it should be more obvious?

Thx
Sel

Quote
porca911
Thanks for the replies guys.

Pedro, if I do go ahead and get it looked at would you recommend fitting the retrofit IMS bearing at the same time or just to inspect it and possibly change the IMS seal? I don't think it's leaking too bad at the minute but I will be monitoring like a Hawk from now.

Marc it's interesting where you say it may be oil from above the RMS and that's got me thinking. When the RMS seal leaks would oil come out from the bottom of the join where the gearbox and engine meet or could it come out from above?

And just thinking out loud here, but as this is the centre of the engine wouldn't spark plug leaks be on the outside edges of the engine as opposed to the centre of the engine? Not sure what the AOS looks like. In fact before just Goggling it I didn't even know what an AOS it was

I was thinking about cleaning the area and then looking to see if I can see where the oil comes from after that. Does that sound like a good idea or do you think that may wash away the evidence and if I look properly as it is currently it should be more obvious?

Thx
Sel

bottom of the transmission (manual) where the bellhousing and the engine joined. From the outside there was no other sign of any oil leak or traces of an oil leak. Once the transmission/bellhousing was removed it was clear the RMS (or the IMS end plate) was leaking.

To me the pic wasn't clear but if you can tell me there is no oil wetness other than at the very bottom of the transmission/bellhousing area then this is pretty good indication the RMS and only the RMS (or IMS end plate) is the oil source.

(Side note: At the time I took the car in the SM told me that sometimes the leak is not the RMS but the IMS end plate and the standard operating procedure was to replace the RMS and upgrade the IMS end plate (not the same thing as the IMS *bearing*) with an improved IMS end plate with a much better seal (3-ribbed rubber ring vs. the single small o-ring of the original) and 3 new micro-encapsulated bolts. These new bolts were to prevent oil from seeping past the bolts.)

When I dropped the car off the SM told me that before the transmission would be removed other possible sources of an oil leak would be eliminated. The car was on the lift and together we looked at the camshafte covers, spark plug tubes, he even shined a bright light on the AOS bellows. There may have been other areas we looked too but I can't remember them. But each area we checked none showed any signs of an oil leak, so the diagnosis was the RMS/IMS end plate. Basically the SM said the trick was to look for any signs of any oil leak *above* the RMS area that could masquerade as a RMS oil leak.

All I'm saying is you want to be sure where the leak is coming from. The RMS is quick to be blamed and it is to blame often enough this is understandable but before one wants to go to the expense of having an RMS replaced he wants to be, or should be anyhow, darned sure that's the source of the leak.

Cleaning the area, then driving the car some and reinspecting the area is a good idea. The leak is not severe enough that there's any risk from driving the car. (I drove my 02 Boxster around 8K miles with a leaking RMS before I took it in. I had a vacation/road trip scheduled and the dealer had no parts in stock and I would have had to postpone my vacation and that would have thrown a big monkey wrench in my plans. The SM said it was ok to drive the car, that he had never seen an RMS leak escalate into something serious.)

'course you still want to be on your toes and if there's any signs of something more amiss than a bit of oil leaking take the proper precautions.

Anyhow, when I look for a leak source I touch the areas that I suspect or that could be a leak candidate. The engine should be cold, and off of course. What I want to see, what I look for is, are any signs of oil on my hand. And just because a particular spot has the hand coming back a bit oily, the test must continue until all possible sources are checked eliminated. It is possible for there to be two or more leaks. For instance if one spark tube is leaking there are 5 more to concern yourself with.

Or if you want to have a professional look at the car that's ok too. In some cases, when the leak source is proving difficult to pin down, a professional mechanic can add some kind of dye to the oil and run the engine then shine a black light at the engine and the oil leak, even if it just starting to seep out past a gasket, will show up.

Sincerely,

MarcW.

... a man's prostate.
Give it enough time and it will develop cancer.
So, if you have over 50,000 miles or more on the original, I would retrofit the new ceramic bearing.
YMMV.
Happy Porscheing,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

... there's a guarantee per se, but LNE recommends replacing it at 50K.
It's a wear item.
Might as well change it when you're there.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Can you believe this, one Porsche specialist I spoke with in the UK today said that they can change the seals (RMS & IMS seal) but if the IMS bearing has play in it they will tell you that you have had it and recommend a rebuild. They don't fit the retro kit! And they have been running for many years. I was shocked and didn't know what to say to them.

Others recommend living with the oil leak until it gets bad. I wonder if fitting a magnetic sump plug and changing the oil every 3/6 months (and seriously checking the oil filter at changes) is a sane option? Thoughts anyone... This does feel like Russian roulette though.

And one specialist say that they use 5w/40 or 10w/60 oil as it leaks less. This doesn't make much sense to me. Does anyone know if this is the case?

Quote
porca911
Can you believe this, one Porsche specialist I spoke with in the UK today said that they can change the seals (RMS & IMS seal) but if the IMS bearing has play in it they will tell you that you have had it and recommend a rebuild. They don't fit the retro kit! And they have been running for many years. I was shocked and didn't know what to say to them.

Others recommend living with the oil leak until it gets bad. I wonder if fitting a magnetic sump plug and changing the oil every 3/6 months (and seriously checking the oil filter at changes) is a sane option? Thoughts anyone... This does feel like Russian roulette though.

And one specialist say that they use 5w/40 or 10w/60 oil as it leaks less. This doesn't make much sense to me. Does anyone know if this is the case?

I'm sure, well pretty sure, there are UK shops that do this. Two I would check with right now are Autofarm and Hartech. If one or both can't help you ask if it can recommend a shop that does the bearing retrofit.

Now just to warn you. IIRC both of these shops do engine rebuilds and one or both might see that as the only solution and turn you down for a bearing retrofit and even be unable (or unwilling) to recommend a shop that does the bearing retrofit. Be prepared to get the polite "bugger off" response, though I doubt you'll get this from either shop. Both as best I can tell are well respected shops and even if neither does the upgrade would be willing to suggest a shop that can help you.

Also, you might check with the company that offers the IMS bearing upgrade/retrofit kit and see if it can suggest any shops in the UK.

If the leak is just an RMS leak then you can live with it.

The trouble is that in some cases the leak can be from the IMS. Now from what I understand and have seen in at least a few pics that the 'leak' from the RMS/IMS area is not that bad. The leak is evident by a bit of oil under the tranny or even a spot on the ground once the transmission is removed and that area of the engine is exposed.

And just because there might be some signs of an IMS leak is not proof positive the IMS bearing is going bad. As I have covered before when my 02 had its RMS replaced (back in '02) the standard operating procedure was to replace the IMS end plate (this is not the bearing!) with a new end plate with an improved oil seal, and use 3 new micro-sealed bolts.

I was told that some leaks blamed on an RMS were in fact due to a leaking IMS end plate/bolts.

I do not know if the leak that is simply an oil leak at the RMS/IMS area differs from that of an oil leak from that same area but due to a going bad IMS bearing.

What does all of the above mean? Well, I do not know if a RMS leak is just a harmless RMS leak, or even a harmless RMS/old IMS end plate/bolts leak, or a leak that signals/is indicative of an IMS bearing.

Switching to a different oil can sometimes affect a mildly seeping oil seal.

Even refilling the engine with fresh engine oil can sometimes diminish a leak. As oil is used it collects water and unburned gas which make the oil more fluid and a bit more prone to making its way past a marginal seal.

If you are running say Mobil 1 0w-40 oil you can switch to an *approved* 5w-40 oil, or even a 5w-50 oil. Mobil 1 makes such an oil (and I just had my 02 Boxster filled with this oil and the Turbo gets the same oil next oil/filter service).

I would not advise you to run a 10w-60 oil. The camshaft/valve lifter bucket contact points are splash lubed from the excess oil that comes from between the valve bucket and its bore in the head assembly. A heavier (10w-60 is 'heavier when cold and when hot) might result in this splash lube characteristic being compromised. (There are other areas of the engine where this oil might interfere with the engine's proper operation, such as in the VarioCam system.) In short the 10w-60 oil probably does nothing for the leak and it could result in wear at the camshaft lobes/bucket contact point.

In a pinch -- and if you are 'desperate' to have the seal oil tight you can select an approved oil that is a group 5 oil. My info is group 5 oils are ester based oils and one characteristic of an ester based oil (besides that they are usually a very good oil), is that ester based oils tend to cause some seals/gaskets to swell slightly and in doing so can fix a mild seal/gasket seep.

The downside is the seal swells, and then if you ever switch away from an ester oil the seal could shrink and the mild leak is something less mild.

Depending upon how you use your car more frequent oil/filter services might be called for. Short trips, cold weather, lots of idling, low speed driving, all work to increase the amount of water/unburned gas content of the oil and these lower its viscosity and this ain't good.

You can check the filter every oil change but the problem is that what often happens is someone finds something in the oil and then goes into a panic thinking the engine is near death when the stuff found is just the engine being an engine, an engine that once in awhile sheds metal and means nothing, unless the metal particles are ferrous. Alum. flakes (tiny flakes) in the old oil from an all alum. engine is like finding sand in the Sahara. Ferrous metal particles in the oil is another matter.

Sincerely,

MarcW.



Edited 1 time(s). Last edit at 03/12/2012 05:24PM by MarcW. (view changes)

What I have done is with the Porsche approved oils list handy searched out some oils and looked into them a bit. Often the info on the web is just some high level sales mumbo jumbo and one is lucky if he knows the SAE viscosity numbers after reading the junk, but sometimes that the oil is a Group IV or Group V oil is mentioned. Sometimes a link is provided that takes you to more details on the oil, its performance data, and sometimes you can even find a link for the oil's MSDS (material safety data sheet).

The MSDS for an oil often gives a list of the oil's ingredients, sometimes.

Sometimes the base stock is clearly named other times a list of CAS numbers is given and then you have to google the CAS # and read the info at the search hits to determine what the chemical actually is.

Be aware of the percentage numbers, too. Sometimes a good ingredient is listed, but its percentage shows that this ingredient makes up less than half, sometimes less than one quarter of the oil's weight. The rest can be mineral oil and a truck load of additives.

Off hand, the only Group V oil that I know of is Motul and IIRC not all of its oils are Group V...

While an ester based oil might help dry up a mildly seeping RMS I would be reluctant to run an ester based oil simply because an ester based oil is harder to come by and probably cost more money than a comparable Group IV. One possible source would be a well stocked motorcycle parts/accessories shop or a large motorcycle dealership.

Sincerely,

MarcW.

Marc, you said something I've never heard before and maybe I've over-analyzed this but here goes. You said, "My info is group 5 oils are ester based oils and one characteristic of an ester based oil (besides that they are usually a very good oil), is that ester based oils tend to cause some seals/gaskets to swell slightly and in doing so can fix a mild seal/gasket seep." My understanding is that the OEM Porsche-sealed IMS tends to fail (if at all) by oil and unburned gas penetrating the seal and diluting the grease inside the bearing and eventually the bearing lacks sufficient lubrication and fails. If so, use of an ester-based oil would also tend to swell the seal slightly on the OEM IMS. Would this not therefore help preserve the IMS seal and therefore the integrity of the bearing, at least as long as one never switched from the Group 5 oil?

BTW, how would I identify a Group 5 oil to use in my car?

Quote
paulwdenton
Marc, you said something I've never heard before and maybe I've over-analyzed this but here goes. You said, "My info is group 5 oils are ester based oils and one characteristic of an ester based oil (besides that they are usually a very good oil), is that ester based oils tend to cause some seals/gaskets to swell slightly and in doing so can fix a mild seal/gasket seep." My understanding is that the OEM Porsche-sealed IMS tends to fail (if at all) by oil and unburned gas penetrating the seal and diluting the grease inside the bearing and eventually the bearing lacks sufficient lubrication and fails. If so, use of an ester-based oil would also tend to swell the seal slightly on the OEM IMS. Would this not therefore help preserve the IMS seal and therefore the integrity of the bearing, at least as long as one never switched from the Group 5 oil?

BTW, how would I identify a Group 5 oil to use in my car?

that if one wanted to prevent IMS bearing (seal) failure he switch to running an ester/Group V oil in his Boxster.

All I'm willing to say is what I've already said that ester based oils can cause some seals to swell slightly and well, you know the rest...

Sincerely,

MarcW.

IMS bearing would be a universal side effect from running an ester based oil.

Many IMS bearings and one assumes then their seals appear to be just fine.

My theory that kind of argues against your theory is if ester based oils were more widely used -- with the intent of helping the IMS bearing seal remain oil/grease tight -- more IMS bearing seals and eventually more IMS bearings would fail. To expand on this a bit if the seal's fit is "just right" any swelling could increase heat and wear at the seal and shorten its life and thus the bearing's life.

I prefer to fix seal leaks the old fashioned way: replace the seal. Now I understand a leaking RMS repair represents a bit of money so there's living with it, which doesn't mean one just has to sit back and watch the stain appear. Were I faced with a leaking RMS I'd consider shortening oil change intervals (due to the driving conditions the oil may thin out and increase its propensity to leak past a marginal seal) but I would not get carried away. My thinking is that if the seal leaked with even 5K mile oil/filter services, I'd either let it leak or take the plunge and have it fixed.

Along with a more frequent oil/filter service schedule, again talking about what I'd do, I'd consider switching to a different oil. If the temps in my area were not too cold I'd switch to a 5w-40 oil or even a 5w-50 oil, approved of course. (Porsche recommends 0w-40 oil for areas where temps are below -25C.) Now if none of the above didn't help, then I might, might, consider switching to an ester based oil, depending upon how easy it was to come by and how much it cost.

Sincerely,

MarcW.

... driving
Cars that are driven have better sealing seals.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna