Paul Hawkins

looks like either the water pump or the thermostat housing is leaking from the spray pattern?

The pulley attached to the pump is solid with no play.

deilenberger

One or the other. Might as well do both, and replace the serpentine belt. Your belt looks like a good illustration of one that "should be replaced now.."

Paul Hawkins

Right, a have a new belt ready to go.
It was going to be today's single project on the Cayenne, until the coolant leak

Petza914

Until you remove the serpentine belt and spin the pulley by hand and wiggle it, it's very difficult to ascertain that it has "no play" because it's always under a pretty high load from the belt tensioner, which keeps you from being able to wiggle it.

Paul Hawkins

Thanks for the tip, didn't think of that initially.
With the belt off, the pulley still has no play.

Wonder if I just swap out the pump and gasket, then put the system under pressure with my AIRLIFT -
will that be enough to test if the gaskets at the thermostat are bad/good

Petza914

Yes, creating vacuum with the Airlift will test the integrity of the system just like creating pressure would. The vacuum needle on the Airlift gauge should hold rock steady for many minutes. If it starts dropping, first see if you have a leak where it's expanded into the reservoir tank. If that's solid and you're still dropping pressure, an ultrasonic leak detector will actually hear the "hissing" of the air being sucked in to pinpoint your leak.

This is a great way to do it as you can troubleshoot without the system being full of coolant and having to drain it all again in the event of a leak.

Just did exactly this with my airlift and leak detector on my 928 and found a defect at the passenger side water bridge.

If the airlift holds vacuum for a while, stick the end in the jugs with the 50/50 mix of coolant and distilled water and fill it up.




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Paul Hawkins

Finally had time this past weekend to tackle this job.
I wound up only needing to replace the Water Pump, and did not have to tear into the rest of the engine to do the thermostat.
After I replaced the water pump I used the AirLift and the negative pressure test held !

So after cleaning the throttle body and mass air flow sensor, and putting in a new serpentine belt as well. I put it all back together and she's running strong again.

The most difficult part of the repair was removing the lower radiator hose to drain the fluid.
It did not want to come off

Petza914

Love it when the project goes as predicted, as they only do that about half the time. Glad you're back in business.