CriticalCommonCooling

Porsche Cayenne: V8 plastic coolant pipe failure (955/957 4.5/4.8)

V8 plastic coolant pipe failure (955/957 4.5/4.8) is a common cooling fault on the Porsche Cayenne on the 2003–2010 cars, and we rate it critical. Putting it right costs $2,000 to $6,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 23 documented faults on the Porsche Cayenne.

Vehicle: Porsche Cayenne
Engine: 4.5L / 4.8L
Years: 2003–2010
Fuel: petrol
System: Cooling

This page covers the Porsche Cayenne as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Porsche Cayenne faults23 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Torque converter or Turbocharger yet. We would rather show none than show a picture of a different part.

What goes wrong

The first-generation V8 Cayenne S and Turbo have coolant pipes made of composite plastic running through the engine valley, and they become brittle and crack, dumping coolant and overheating the engine, sometimes stranding the car. The problem was so widespread Porsche faced a class action. Coolant leaking at the bell-housing can also ruin the transmission's torque-converter seal. The proper fix is an aluminium pipe upgrade so it never fails again.

What you would notice

Sudden coolant loss and overheating
Sweet coolant smell and steam
Coolant pooling around the transmission bell-housing
Low coolant warning

How to check it

Where to look. Coolant pipes in the engine valley under the intake, running to the rear bell-housing

Ask directly whether the coolant pipes have been upgraded to the aluminium kit; on a V8 this is the single most important question.
Look for coolant residue in the engine valley and around the bell-housing at the back of the engine.
Check the coolant level and history for top-ups.
A V8 without the pipe upgrade should be priced to include the job.

Parts involved: Torque converter, Turbocharger.

What it costs to put right

$2,000 to $6,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Have the coolant pipes been upgraded to aluminium?”
“Any overheating or coolant loss history?”
“Is there coolant residue around the transmission?”

Now check the Porsche Cayenne you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

FCP Euro first-gen Cayenne engine guide (955/957)
Rennlist 'Coolant pipes A-Z' thread
911uk.com 'Cayenne S overheated due to coolant pipe' thread

Porsche Cayenne buyer questions

Is v8 plastic coolant pipe failure (955/957 4.5/4.8) serious on a Porsche Cayenne?

We rate it critical and common on the Porsche Cayenne. The first-generation V8 Cayenne S and Turbo have coolant pipes made of composite plastic running through the engine valley, and they become brittle and crack, dumping coolant and overheating the engine, sometimes stranding the car. The problem was so widespread Porsche faced a class action. Coolant leaking at the bell-housing can also ruin the transmission's torque-converter seal. The proper fix is an aluminium pipe upgrade so it never fails again.

How much does it cost to fix on a Porsche Cayenne?

$2,000 to $6,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Porsche Cayenne years are affected?

Our research records this fault on the 2003–2010 Porsche Cayenne. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Ask directly whether the coolant pipes have been upgraded to the aluminium kit; on a V8 this is the single most important question. Look for coolant residue in the engine valley and around the bell-housing at the back of the engine. Check the coolant level and history for top-ups. A V8 without the pipe upgrade should be priced to include the job. Look here: Coolant pipes in the engine valley under the intake, running to the rear bell-housing