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IF YOU'RE THINKING OF BUYING A 958 - READ THIS FIRST!
More or less like the 955 thread with a similar subject - but I'm hoping this one will actually be useful. Think of it as a place to list common failings - things people should check or look out for if they're considering buying one of these marvelous machines. I hope the moderators will consider making this a sticky in the 958 forum.
Please feel free to comment/add info!
UPDATE: Thanks to the MODERATORS! They made this thread a sticky. Now lets make it useful!
Last edited by deilenberger; 12-17-2018 at 09:29 PM.
For MY 2011 (some 2012s?), make sure the camshaft bolts have been replaced on the V8 motors (S, TT, GTS) per the Campaign or get it done ASAP.
Not really a problem, but surprises some peopl: For a diesel, know that the oil change interval is 5000 miles rather than 10k like the others (and the VW/Audi uses of the 3.0 TDI).
RANGE: If considering the purchase of a 2011 /S or CTT - one should be aware of a problem that people have experienced with the engines on these models. (This also may effect a very limited number of 2012 V8 models - ones made at the end of 2011.)
PROBLEM: For a limited range of time - production of the V8 engines included "Variocam" adjusters using an aluminum bolt. This bolt has been known to fail in service. When it fails it can range from a fairly benign failure to total engine destruction.
Porsche issued a "Workshop Campaign" (something they use when they'd rather not list it as a warranty) covering a limited range of VIN#'s in the USA. In China and Japan they also issued actual recalls - for a greatly expanded range of VIN#'s compared to the USA.
The campaign (WC-22) consisted of having the service department replace the Variocam adjusters with ones having a different bolt holding them together.
The problem is - there are quite a few reported bolt failures outside the VIN range that Porsche covered under WC-22. They have been extensively reported on in threads on this forum and others:
The last is probably the most extensive source of information on the issue.
WHAT TO DO: I would suggest several things
Check if the V8 engine you are considering buying has the bolts that are questionable, or if they have already been changed.
If they have been changed - this is a non-issue for that vehicle.
If they haven't been changed - get an estimate from a local Porsche dealer on the cost to you to have WC-22 performed on the vehicle. They will likely tell you the vehicle doesn't need it since it isn't covered under the VIN# range - but I'd assume caution on that subject. Enough have failed outside the VIN# range that it IS a concern.
Cost to do the job - out of pocket for the owner - has ranged from $2,600 to around $4,000. It probably is not a DIY since special tools are required to time the engine correctly.
Failure of the bolts at best - all the bits are easily found, and no valves have been bent or pistons damaged - is the same as the cost of replacing them before they break. At worst - things like bent valves, damaged cam sprockets/chains, damaged camshafts, damaged pistons - have all occurred, making engine replacement necessary. A new engine will cost around $35,000 installed. In most cases this makes the vehicle worth very little. A used engine may range from $5,000 and up installed. And the used engine may need to have WC-22 performed on it too.
CHECKING THE BOLTS: There is a simple visual test for the questionable bolts. It should be done on any V8 engine 2011 (and early 2012) Cayenne you're considering. Using a dental mirror and a mag-lite, look at the bolts on the back of the camshaft sprokets. If the bolt head has a center pin in the Torx recess - it is one of the questionable bolts. "Good" bolts do not have that center pin.
BAD BOLT - Center Pin
GOOD BOLT - NO Center Pin
Dental mirrors can be found at your local chain pharmacy.
UPDATE: Porsche has issued a recall in the USA, Campaign AH08. As of 9/01/17 - no parts are available yet. More details will be added as more is known.
UPDATE: The recall has "3 scopes" - ie - the amount of work done. #1 simply replaces the defective bolts, leaving the Variocam adjusters installed and not disturbing the timing. A one day job if it all goes OK. #2 is - replace the Variocam adjusters - if any loose (but not headless) bolts are found. This requires more disassembly and retiming of the camshafts when done. Expect it to take 1-2 days. #3 is if the bolts have sheered off and the heads are missing. The work here depends on what they find. If they can find all the bits of the sheered off heads - and the cams didn't lose timing, then they can replace the adjusters and be done with the job. If any bits of the heads are missing - then disassembly of the engine will be done until they're found. If the cams lost timing, and the bolt heads are missing - depending on what Porsche decides - the vehicle may get a new engine. Time estimate on #3 - unknown since the actual work done isn't known. Dealers have started getting the parts (1/2/18) and are I've seen reports of them doing #1 and #2. I have not heard of a #3 scope job yet - but I'm sure there will be some.
Last edited by deilenberger; 04-16-2018 at 03:25 PM.
RANGE: ALL gasoline engine Cayennes. Not an issue so far on hybrid or diesel Cayennes (different transfer cases.)
PROBLEM: Unfortunately - it appears that failure of the "transfer-case" on the 958 is not uncommon. The transfer case is a mechanical device that splits power between the front and rear axles on a 4 wheel-drive vehicle. In the case of the Cayenne, it does this using a multi-plate stepper-motor controlled friction clutch.
For some reason(s)* - some of the transfer-cases start to experience slippage of the clutch mixed with grabbing of the clutch - causing a lurching sensation on acceleration. It is most commonly felt in 2nd and 3rd gear, but as it becomes worse it can be felt in other gears.
This has been recorded as happening as soon as 15,000 miles, and there are vehicles with over 100,000 miles that have not experienced it.
Cost of replacing the transfer case seems to be around $4,000 - being done by a Porsche dealer. Currently there is no aftermarket source of rebuilt cases. Many Porsche dealers are now stocking the cases - which is telling in itself.
Can it be avoided? Perhaps. There are a number of people (myself included) who have changed the "lifetime" transfer case fluid - and had improved transfer case behavior. People have used the Porsche specified fluid (recently changed in part #) and some aftermarket fluids listed by their manufacturers as meeting the Porsche specifications. The fluid change is actually quite easy, and inexpensive. Many of us are considering adding it to our 10,000 mile oil change intervals.
When test driving the vehicle - do some light acceleration in full automatic mode - accelerating through 2nd and 3rd gear. Be aware of any "unsmooth" feeling to the acceleration. Listen for any noises that appear to come from the driveline. Driving next to a center-divider with the drivers window down may be helpful. Listen for any odd noises (cracking walnuts has been a sound used to describe the clutch noises.) In a parking lot do some tight U turns, left and right - listen for noises, feel for unsmoothness.
If anything is observed - consider the possibility that there may be a problem. If the vehicle is a CPO vehicle - request that the dealer service department check the operation. If the non-smooth feeling goes away if they disconnect the stepper-motor on the transfer case - it's 100% a transfer case issue (pretty much the acid test for it.) If the vehicle is not a CPO car and has no warranty, factor a possible $4,000 repair into your bargaining. It may not need the repair - but it may very well need it.
If nothing is observed - and you decide to purchase the vehicle - if at a dealer - ask to have all the driveline "lifetime" fluids changed before delivery. Don't take "no" for an answer. This is a case where prevention can save you a lot of money.
* = POSSIBLE REASONS FOR FAILURES: Porsche recently (03/17) redesigned the vent for the transfer-case. The case has an air-scoop mounted under it that directs cooling air up around the case. In going through puddles (or rivers) where the water level may reach this air scoop - the scoop is going to scoop up water, directing it toward the front output shaft of the transfer case, which will spin it up toward the top of the case where the transfer case air vent is located. That vent is not particularly well sealed. Porsche added a "slinger" to the output shaft to redirect the water, and moved the transfer case vent up into the engine compartment. Unfortunately - it appears difficult to impossible to install the new vent kit without removing or dropping the transfer case. So far no one has reported doing this job.
There is also reason to believe (see the threads) that the oil may break down in time and become less effective at lubricating and cooling the mutli-plate clutch assembly. This breakdown appears to be temperature related - as a distinct burned smell is often observed when the oil is changed. So far - on cases where the oil has been changed - improved behavior is commonly the result. In some instances multiple changes may be suggested. Luckily - changing the TC oil looks to be about the easiest job you can do underneath a Cayenne. Drain and fill plugs are right in the open staring at you.
And finally - the reason for the heating of the fluid may be related to use of different diameter tires - or even badly worn tires on the axles of the car. Changing just the tires on one axle is not recommended. That results in different rolling diameters which may cause more required slippage in the clutch assembly than normal. The slipping will cause additional wear and heating of the oil that cools the clutch.
Last edited by deilenberger; 04-19-2017 at 12:32 PM.
I'm glad that you had mentioned that both the Diesel and Hybrid's are largely exempt due to the different x-fer cases.
Hi Ben,
That's based on anecdotal evidence - so far I've seen no reported failures on the diesel or hybrid. The cases are different - but how isn't clear to me yet, aside from a different power distribution. I believe the cases used on the non-gas engine vehicles are basically the same as the latest VW Tourag case.
At least from all that I have seen on ClubTouareg, I have also not come across one failure of either the x-fer case or the differentials and these are 2011+ TDI's.
I don't know if the Touareg and the Cayenne diesels share the x-fer case and diff's. I do know that the oil, cabin and fuel filters are the exact same as are the windshield wipers both F and R. Same with the floormats as the floorpan is the exact same.
At least from all that I have seen on ClubTouareg, I have also not come across one failure of either the x-fer case or the differentials and these are 2011+ TDI's.
I don't know if the Touareg and the Cayenne diesels share the x-fer case and diff's. I do know that the oil, cabin and fuel filters are the exact same as are the windshield wipers both F and R. Same with the floormats as the floorpan is the exact same.
Everything I've heard is that the diesel driveline is identical on the Touareg and the Cayenne diesels. Same everything.
More or less like the 955 thread with a similar subject - but I'm hoping this one will actually be useful. Think of it as a place to list common failings - things people should check or look out for if they're considering buying one of these marvelous machines. I hope the moderators will consider making this a sticky in the 958 forum.
Please feel free to comment/add info!
UPDATE: Thanks to the MODERATORS! They made this thread a sticky. Now lets make it useful!
When I saw your initiative for a 958 sub forum granted, I was specifically going to nominate you to make this sort of thread. I've seen you posting quite actively in the main cayenne forum and trust you've got your thumb on the pulse of what is being discussed.
I was a 955 owner until recently and am very strongly considering moving to a 958 this summer. I miss the CTT terribly. Beyond variocam bolts, I'd like to know what I should be expecting and at which intervals. (I believe I had every single last one of the documented 'known' issues happen to my 04. It got to be too much.)
Can I request that you continually edit the top post here to make this sticky-worthy thread even more useful to those clicking on it to get the scoop on 958 before purchasing?
Can I request that you continually edit the top post here to make this sticky-worthy thread even more useful to those clicking on it to get the scoop on 958 before purchasing?
Thanks for the kind words.
Sure. Not a problem. Something I did on another (BMW) website where I was a moderator - was make a sticky thread that pointed to the DIY's from around the web relating to the model E46-M3) the forum was for. People would regularly contribute entries to it - and I'd add them in the correct area.
If there is any management encouragement here, I might consider doing it for the 958.
could the transfer case issue be limited to Turbos? The case is not sturdy enough to handle 500hp?
This could be a simple issue if they're using the same transfer case on the V6 and V8 - and the turbo. You design it for 400hp - 500 just tears it up - even though you technically over-engineer a little.
could the transfer case issue be limited to Turbos? The case is not sturdy enough to handle 500hp?
This could be a simple issue if they're using the same transfer case on the V6 and V8 - and the turbo. You design it for 400hp - 500 just tears it up - even though you technically over-engineer a little.
The answer is - no - it's not limited to turbos. It is perhaps seen a bit more often on the turbo vehicles. It happens to any of the gasoline engine 958 vehicles. I have seen nor received any reports of it happening to the diesel or hybrid.
It's not quite as simple as it being under-designed for the power. IMHO - there are several issues going on - one of which is very simple to avoid. Don't believe Porsche when they say it's lifetime fluid. It's only lifetime fluid if you dispose of it when the life of the transfer-case is up - due to failed fluid.
The links for transfer-case issues are given above - I'd REALLY suggest reading them before asking questions. You'll find most of your questions have been answered and you'll avoid pissing off the people who can best answer them for you.
Update!
As it turns out they're saying now that it's not the transfer case, it's the transmission. They first tried replacing the TCU with no improvement. New transmission arrived today and I'm supposed to have it back by early next week.
2014 Cayenne Turbo S with 41k miles.
04-18-2017, 01:36 PM
IF YOU'RE THINKING OF BUYING A 958 - READ THIS FIRST!
