What are the electric change-over valves? Several need to be replaced on my car.

I assume they control the vacuum in the combustion chamber of the engine. If one isn't performing appropriately, what are the symptoms /problems?

 

deturney posted this on Rennlist:
"My 991S is at a Dealer now for PSE installation and an early first oil and filter change. While there, they are doing the WC-43 campaign too. My coupe was built 1/13/2012.

The Dealer printed out a WC-43 Tech Sheet for me, my take on it: some Electric Change-Over Valves are to be replaced. Porsche is concerned that they might not be sealing properly allowing moisture in, causing the valves to malfunction over time. This affects the PDK and PDK Clutch Cooling system and under extreme conditions (track days for instance) could cause the PDK trans or clutch to overheat.

There are two valves for sure that will be replaced on the PDK, and any other thermal management change over valves of the same design will be changed too, for a total of 5 to 8 valves per affected cars.

If anyone wants a copy of this Tech Sheet, just PM your email address and I will scan and send it."
http://forums.rennlist.com/rennforum...e-991-a-4.html

ChuckJ

 

I had 5 replaced, and I don't have PDK. Standard manual here.

And the dealer definitely referenced that were feeding the engine. And i finally got a look at said engine when the spoiler was off. It is beautiful.

 

Yes it is!

ChuckJ

 

I think they are switches that actuate devices or levers or something or other that reroute air, fluids, or gases.

 

I think they may be the valves that change the many modes of the cooling system (including the PDK). It seems they have changed from pneumatic types which were less expensive, but also less reliable. The exact term "change-over" is not specifically used in the service manual, but it's close and there are like 7 cooling modes that have to redirect the fluid. They seem to be worried about moisture getting in the valves themselves.

ChuckJ