looney2n

Saw this post in another area of the forum and am waiting on a reply for Steve at Rennsport.

"Could this be in our future?"

Thought it might be something you would want to follow...............

https://rennlist.com/forums/993-turbo-forum/446224-thrust-bearing-failure.html

Alan Smithee

The 993TT motor has almost nothing in common with the 997 motors...

looney2n

That may be true, but what may be common is the issue of clutch depression required for starting.

A reliable source indicates that this issue can be present in all 911's 1987 and later..............

Sure would like to hear from other "reliable" sources as well.

abe

Not only is this a 993TT, but they are in Australia! okay, its a joke...this may apply to us to. On a more serious note, it makes me wonder if using Mobil 1 0-40 is that great of an idea since all engine parts may not be lubricated when you first start the engine. Wonder if in the future we will be hearing about other engine part failure as a result of too thin oil.
just a thought...
abe

1999Porsche911

Many of us already made the leap to avoid Mobil 0W40 many years ago. The risk, as described above, was even specifically mentioned as a potential problem using the Mobil Water as was the risk to valve guides, intermediate shaft and other critical componants.

IMO, only the uninformed, stubborn or outright mindless would use Mobil 0W40 oil in their Porsche, especially when forums like this have drawn attention to its weaknesses for the past several years. There are plenty of other oils both on and off the approved list that are far superior. It is, however, very good to use for lubricating door hinges and engine flush.

ADias

1 - Can you even start a 997 without pushing the clutch? Isn't there a microswitch at the end of the travel that has to be engaged?

2 - M96 and newer engines may need 0W oils, as they have very small oil passages which require light oils.

abe

I hate to be "uninformed" but they keep telling us at Porsche and 997 site that mobil one 0-? is the only way to go....what am I missing here?
abe

1999Porsche911

Who is "they"? Mobil 0W40 is only one of dozens of oils Porsche says you can use and there are even more oils you can use that are not on their list.

ADias

On a new car which is not a garage queen I would use 0W40. I think that the avoid 0W school is a bit paranoid.

abe

...I better run along to the air cooled 911 site.
Thanks,
abe

Edgy01

Here goes our "oil expert" from chicago who refuses to share his credentials.

997, esq

Doesn't the clutch have to be depressed to start? If so, I don't see what can be done about this. Not sure using different weight oil is the right solution. And also not sure if I am "uninformed, stubborn or outright mindless," but perhaps a bit of all three.

sandwedge

Not being facetious......just curious. Why would car manufacturers (BMW likes it too) that sell $100K cars with $20K engines warrantied to 50,000 or 100,000 miles recommend motor oil that in your opinion could be substituded with WD40 or cooking oil?

I don't know that either BMW or Porsche has a reputation for being exceedingly generous so why would they NOT go to great length testing every oil available and recommend or demand use of the one that in their opinion offers the best protection = least warranty issues? What do they gain by recommending substandard oil for their warrantied engines?

looney2n

This is one professional's opinion:

"The Federal DOT mandated a clutch pedal interlock that requires clutch disengagement to start the car and thats why the thrust bearings wear out prematurely. Its exacerbated by the thin oils needed to operate the VarioCam hydraulics."

1999Porsche911

Porsche does not state that Mobil 0W40 is the best oil for your engine. 0W40 is just one of the “approved” oils and is the factory fill as a direct result of the substantial financial contribution Mobil marketing makes each year to Porsche.

There are dozens of oils on the approved list, including 5W50. Even 15W50 was on the approved list and for some reason, Porsche decides to remove it, even though it used to be factory fill and has been used in Porsche engines for more than 25 years.

Much of the push in the use of cooking oil grade oils is to deliver better fuel efficiency as companies jump on the GREEN bandwagon. As with all choices in life, it comes with a compromise. This might include less shear protection, less consistency in lifter performance, leaks, idle protection and oil consumption.

The myth that you need 0W40 for proper variocam operation has been argued here many times. No matter how many “experts” or websites claim that the variocam operates better with 0W40 over other oils, it will remain a myth.

Unfortunately, the negative effects caused by using improper oil are often not evident in the short run. However, there are some symptoms that can help you determine if your oil is protecting your engine properly. They include oil leaks, oil usages, rough or inconsistent idle, engine rattles/noises and low oil pressure. Assuming that all oils provide adequate lubrications, cooling and cleaning, these symptoms may be telling you to find better oil.

Oil leaks can be caused by a physical weakness in a seal and are often aggravated by the use of oil that has inadequate conditioners for keeping seals soft or additives that actually cause seals to shrink. Mobil 1 has long had the reputation for harming engine seals, going back 30+ years. Once oil gets between the casing and seal, it is only a matter of time before the leak increases.

Oil burning has always been a characteristic of some Mobil synthetic oils. Just as their 0W40 does not cling to parts for very long due to its thin properties, it often passes through mechanical barriers such as seals and rings when other, better oils will not. In modern engines, this oil burning directly and substantially decreases your engines performance.

Many engines that use 0W40 experience rough idles due to the inability of the oil to maintain proper pressure in the lifters. This is evident in engines that have a valve tick at idle when warm. Lifters are designed to main 100% contact with the cam and any noise indicates that they are not. You may also notice a slight loss of pull at high engine rpm’s due to reduce lift.

Many on this forum have stated that their warm engines have and idling oil pressure as low as 7 psi. This is potentially catastrophic for an engine. Pressure (regardless of what oil is used) is required to keep parts separated from each other. Too little pressure may allow parts to bang together, especially during low rpm loads.
Many also argue that thicker oil will not get to the moving parts of an engine as quickly as thinner oil will. They argue that engine oil pressure is proof of this. The fact is, an increase in resistance, which causes an increase in pressure, does not automatically translate into less flow. Your oil pump moves the same amount of 15W50 as is does 0W40 under any temperature above 25F. In addition, a 15W50 leaves more oil on engine components after shut down, for a longer period of time than does 0W40.

My point is, if you experience any of the problems I mentioned above, why wouldn’t you try a different oil? Any oil other than Mobil 0W40 would be an improvement. Try a 5W40 or 5W50 if you need to use oil approved by Porsche. For those looking for the best all around oil in warmer climates, move to a 15W50.

Marketing is a powerful tool and, unfortunately, many accept marketing hype as fact. SELDOM is this true in any industry or for any product.