Purekoryo

Do you guys know where the COV is for the coolant?

I have this issue as well but my warning light turned red! Turned the heater and wasn’t blowing hot air either.

I only see the vacuum lines to PSE. After I pulled and installed the PSE vacuum lines again, it seemed to go away but I’m thinking it some how wiggled a vacuum line to the COV somewhat back in place but need to find it to be sure.

The other variable is that this was after I installed sport cats and had to pull my PSE muffler along with their vacuum hose. But I specifically remember making sure to plug them securely in place. Also the test drive right afterwards was fine until this morning. I’m not sure if it matters much but I noticed I didn’t secure the passenger side PSE vacuum hose on one of the small brackets. I then snapped it back in place. Again, not sure how this would affect anything as the hoses seemed to be pretty secure (took a bit of force to pull it back off).

And lastly I checked the coolant and was at max level. Would just taking the reservoir cap off release any air?

Kurtis370gen2

Went to RPM and they did a vacuum test and found the coolant and vacuum is running without any issues so unfortunately not quite sure what the issue is. They are currently in contact with Porsche Technical to gather knowledge on what might be causing the light to come on and will be investigation further when my car is next in. Will post an update asap.

Purekoryo

do you know for sure if they went through the steps to actuate each valve? They cant just test it while car isn’t running. If they have a decent enough diagnostic tool, there is a feature where you can go through this test. My foxwell nt530 had this feature, although my issue was apparent (water pump leak). If you have PSE, also possible the diagram in the valves may be leaking, which you can’t see but should be able to hear it during the test (in vacuum, again using the diagnostic tool).

Kurtis370gen2

I don't know for sure, but they had the car in for a couple of days so I'm sure they did. All eight valves have been replaced too so you'd imagine it's all good. I have seen about the water pump being the cause on other forums but not sure if that's the case for me yet. I also don't have PSE. Thanks for your prompt response and knowledge too.

jskenefick

I had a coolant system fault message. All COV were checked and one was replaced. During the test drive, the fault returned, They ended up replacing the vacuum pump, one of the COV and a Switch Over Valve

titleistaddict87

Question: if you interrogate this with an OBD2 reader will it give you more info on which valve?

koala

Unfortunately not, which is what makes this tricky to diagnose in some cases

AdamSanta85

Yep, pull the wing and hope the detached vacuum line or bad COV is one of the more obvious ones.

Porsche really did a number on the vacuum system. Such a rats nest of loosely attached vacuum lines.

Roswell88

I’ve been following this thread.

Can the vaccum hose be taped to prevent it from popping out again? My exhaust COV hose came loose & I would like to find a permanent fix.

AdamSanta85

Where did it pop off? If by the muffler you can replace the one time use clamps with a fuel injection clamps

If it popped off by the solenoid you could replace the hard plastic slip fitting lines they use with rubber vacuum line and barbed fittings.

Roswell88

Here is the picture I got from the shop, what you think?

titleistaddict87

Small hose clamp that my 964 hoses seem to be littered with??

AdamSanta85

Yea thats the in engine bay lines. You could replace those hard clear stuff that slips inside those rubber fittings with just a rubber line that goes over the barbs which is much more secure.

Roswell88

Thx for the advice 🙏

It’s such a bad design, I was shocked to see this on such high end cars.

titleistaddict87

Well I am very happy to report that the Foxwell tool tests each COV for you. I bought the NT530 and it just arrived today. Under the Active Test section you can select each valve for testing and it returns either 100% or 0% for functioning or not. Haven't had a chance to test the 991 yet but tested another car and it worked flawlessly. You can hear the valve clicking open and shut. Hope this makes it easier for others to also test without having to go down a rabbit hole of replacement / exploration.