Porsche Cayenne S DFI Coolant Leak

Many people thought the leaking coolant pipe issue of the early 955 Cayennes was a thing of the past and that the newer DFI motors did not have this failure. Well, yes and no. While the pipe design has greatly changed, there is still one plastic pipe under the intake, in addition to a plastic coupler for the coolant distribution housing. Unfortunately, this coupler is known to leak due to the plastic/oring setup.

Same presentation. Coolant leaks in the valley of the V8 engine, drains down the back side, through the torque converter area and out the bottom of the bellhousing. Left un repaired for too long, and the coolant will ruin the torque converter seal.

The DFI motors are quite a bit easier to work on for simple maintenance.

Intake removed to check the valley.

And pooling as expected. The one remaining long plastic pipe is shown in the picture. This too will eventually fail.

Between the waterpump housing and the coolant distribution housing is the plastic coupler with the o-rings. You can see the coolant crust around it where it was leaking.

So off comes the waterpump, then you must pull the thermostat and plastic coupler.

And the housing out. The updated housing comes with new orings.

And since we are in there, the thermostat will be replaced as well. With 75k miles on the clock, no point using the old one or an old waterpump.

Thermostat assembly.

And an empty cavity. Tomorrow I will reassemble with new parts.

And since we have it apart, might as well throw in new spark plugs since we are right there.