GR8UK

Not sure where you received this diagnosis, but I highly recommend a second opinion. I replaced 5 COVs, as it turned out, none of them needed to be replaced. This is the first place the PIWIS tells you to go. Find a mechanic who has successfully dealt with this issue, otherwise they will continue to throw parts and labor at it. Looks like you're in the Chicago area, try Ron Barnabas' shop in Batavia, ask for Mark.

barrios35

Porsche Dealer. All under warranty

Thanks for the recommendation though. Will need one once it is out of warranty.

barrios35

Mark from Napleton? I have dealt with him before with my Cayenne. We did not go well after they dropped a refurbished NAV and it went bad less than a year of install, draining my battery. Ended up pulling myself and installing aftermarket.

kenny29

With the sheer amount of COVs that appear to have failed with so many cars, you would wonder if Porsche have ever thought of going in another direction and removing these completely with future engines. Surely this has got to be a real pain for them worldwide having to repair/refit, not to mention the sheer grief this has caused so many owners?

911ofborg

Thanks to this thread my PSE is back in action. I had to use some small hands to get to the PSE COV. Ended up cutting off the vacuum lines since they were stuck on there good. I should have changed the rest while I was in there. The PSE COV looked fine visually, but my PSE would not activate. Now it works on demand as it should. The COV that controlled the sound symposer was melted ... I am not sure if I noticed much change on the sound symposer , I need to see if the previous owner blocked it off. Either way the COV was replaced with the F revision. I had C on my car (2014). I see service history for 1 fix for heater at 4K miles with the previous owner, not sure what revision that COV is that they likely replaced.



Fat and split COV. It looked melted.

Jack F

Seems like version F is the most current as of Nov 1, 2020. Holy cow. So many revisions.

asellus

Kinda crazy for a jellybean part.

X51

Apologies in advance for not reading all 171 prior posts, but is this limited to 991.1s, or is it a lingering issue with 991.2s?
Thanks.

menzzer37

I replaced my heater COV today with the new rev F unit. No bulging or swelling on the Rev B I replaced. Still no heat...
I moved the vacuum lines over and used the new adapter harness. I even checked the physical coolant valve canister and sucked on the hose to ensure it would open and close (which it did).

Before I changed it, the heater would work so long as you didn't adjust it... now I've got nothing. Anyone have ideas?

VII7

I'm drinking right now but from your description you might have a problem with the blender Servo in the ac case.

Carl Over

I watched a yt vid about COV issues. The guy said that many issues stem from the PSE COV and replacing that was recommended. Are all COV the same part number? If so, what is the current part number?

menzzer37

Is that something I can get into? That's what my Indy suggested too. Is it up front with the battery?

Another weird thing related is sometimes when driving 60-70 I get a high pitched squeal from the blower fan... It also pressurizes the cabin enough to nearly pop your ears. Very odd...

GMTurbo

Hi there,

Are these also called 'Hydraulic Valves'?

I am looking at a vehicle history and they were replaced for 'Valve Lift' and 'Camshaft Controller' but I do not see them on this diagram.

Thanks in advance!

Greg D.

I don't think so, the COVs are vacuum valves controlling ancillaries mostly, like exhaust, heater, stuff like that. Your stuff "hydraulic" sounds oil operated inside the motor.

flgfish

Agree, anything to do with valve lifters and the camshaft are definitely not related to COVs.