Porsche Cayenne 958 S overland

[Katanator]

So with the project standing still, basically complete except for one small, or not so small issue, I am making a thread.

Cayenne 958 S with the 4.8 V8
160 000 odd mileage
Car is one owner and super clean, interior and engin immaculate
Full Porsche history

Idea is to build an overland, enjoy, and then resell.

Being mechanically inclined I always end up digging too deep and then repairing stuff, but hey its the journey that counts.

Overland wise im doing the following:
30mm raise with imported spacers like Eurowise kit
Fulle underbody stainless protection, designed by me
Roofrack and full size spare
Upgraded tyres to Goodrich KO2 265 65 18, roughly from 29" to 31.5"
New replaced rubber floormats

 

[Katanator]

First things first, did an oil change with Motul Excess 5W40 gen 2, upped from 0W40 and best quality to hopefully protect engin and keep bores unscored.

Changed all fluids, especially Transfer case fluid which can be problematic on these. Diffs, gearbox, brakes and power steering fluids changed as well.

Inspected oil filter and found some extremely fine non magnetic silver dust/flakes.

Did borescope as first priority but bores looked good as expected for a car with average 10 000km service intervals by Porsche.

So the hunt is on.

 

[Katanator]

First thing that came to mind is bearings, but hey, oil pressure is good, very cold and decent when hot 1.4bar.

Checked a few for reference and lots of them idle hot at much lower pressures.

The engin did make a strange GRRRRRRR sound from the lower front but only at hot idle, had me pointed towards something losing pressure or tension when the engin is hot and oil pressure is at its lowest. Sound dissapering above 1200 rpm as soon as pressure builds.

So project went on and the hunt continued.

 

[Katanator]

Engin in all her glory, as clean as can be:


Testing wheel sizes:

Fitting roofrack:


Classic cayenne issue, one doorlock not working and the window visor motor plastic gears are broken, imported a repair kit.

 

[Katanator]

Undertray designed and fitted, will fit for a Touareg and 957 Cayenne as well:

 

[Katanator]

After all the work here she is in all her glory after adding an Avery decal for the finishing touch:

Forgot to mention had the drivers side right bottom part of seat replaced, the typical area that shows you if quoted km's are genuine, more than half the Cayennes I viewed had tampered mileage.

Roofliner was replaced.

And added custom rubber floormats for the muddy days.

 

[Katanator]

New remote rubbers from TEMU, yes some parts may be replaced with TEMU junk, they look beautiful.

 

[Katanator]

Back to the GRRRRRRRRR issue, driving and diagnosing. After the first month or so I got my first check engin light.

Code P1373

VVT and cam adpation related.

I imported a Foxwell NT530 Porsche specific to diagnose.

Found the camshaft adaption values to be on the upper edge of comfortable on bank 2. Indication of timing chain stretch. But still seemed reasonable.

 

[Katanator]

Having some hope that it is the VVT solenoid at the lower back of the block I ordered an OEM one on Frugo. Replaced this past weekend but cam adaptions stayd elevated.

Clueless searching on youtube for videos showing engin internals to try and figure out what could make the noise, oil pump and chain drive was suspect but oil pressure was good.

Timing chain does not rattle with stethoscope on the timing cover.

 

[Katanator]

Alas I found a video with a guy stating that timing chain plastic guides on these are destined to fail.

I have been back and forth on chatgpt with every possible iteration of the symptoms, pointing towards resonance, torque converter, even went to webuycars and had them fire up 2 similar cars to hear if the sound is not maybe normal.

Nonetheless the guy on youtube ran a borescope down the oil filler cap, so did I, low and behold timing chain guide plastic broke, off the rail and about 1cm shifted to the side, and that is on bank 1, not even the one with excessive cam adaption. Can bee seen as the red/brown plastic piece on the photos, it also needs to cover the top shiny end of the rail, that piece is completely gone.

This also explains the light silver shimmer in oil filter as guide and casing rub against the chain when it is slack at hot idle.

Sigh of relief that the engin is as healty and clean as should be expected of one with its history and its but a mere timing chain guide
I will be importing a IWIS chain set and have it replaced, too much work for my garage that needs clean floors.