Ongoing change over valve issues on 991
#136
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My cooling system fault code comes & goes, so I lived with it for a bit, and finally decided to use the winter break to replace the other 5 COVs with F parts. I have the car apart (bumper off, spoiler off, airbox out, undertray off) and I can say positively that the three valves they changed are the three easiest ones to change... the two on the airbox, and the one for the heater right in back on top. The five buried ones, nope, I get to do those.
#137
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OK, what kind of sorcery did you use to get the hoses off? The easy to access ones I can manage, but the others - the hose on the vacuum input side absolutely refuses to come off. I've tried everything I can think of, short of cutting them out. Any tips?
#139
#141
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Well, the "cooling system failure" has won. I guess I'm taking it to the dealer, or a local indy.
I've had three COVs changed to the -F part in the past, so I bought 5 more to change myself (under the impression that my car has 8 total). I only was able to change three. I could only find 7 total on the car (a 2015 C2 with PDK and PSE). I had two on the airbox, one on the right side wheel well for the heater, two under the car (one by the transmission, one up above the driver's transaxle) and then two to the right of the engine. The stuff I've seen (Plenum's blog for instance) says my car should have 8, and that there should be three COVs on the right side of the engine. I can see a third COV mount behind the front two, but there's no COV there. I traced the vacuum line as well as I could and didn't find another. The mystery remains. So, obviously I didn't change that one. I also could not get to the one above the transaxle to change - I could see how to do it on a lift, but on jack stands, I couldn't work out how to do it.
So I buttoned the car back up with the three new valves, started it up, and the codes remain. My PORII says the codes (P1432 and P1433) are current (both listed as vacuum leaks) and clearing them does nothing as you'd expect.
Pulling the bumper, spoiler, air box and bottom covering is pretty easy, and putting it back together is easier than taking it apart. Getting the vaccum line connection off the COVs is a huge pain. Where I could get two hands in, I was able to work it off with a small screwdriver. In two cases, I just cut them off. The other two connectors are easy to get off, as is the electrical connection.
FWIW, my car had -C COVs from the factory. It was built on 7/30/14, or so a sticker under the bumper says.
Here are some pics that I happened to snap during the process.
Car up on jack stands & unbuttoned:
![Name: pSaK9djh.jpg
Views: 1682
Size: 174.3 KB](https://rennlist.com/forums/attachments/991/1343849d1683254620-ongoing-change-over-valve-issues-on-991-psak9djh.jpg)
Two COVs on the airbox:
![Name: eFvrX85h.jpg
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Size: 108.9 KB](https://rennlist.com/forums/attachments/991/1344216d1683254620-ongoing-change-over-valve-issues-on-991-efvrx85h.jpg)
COV on the underside of the car by the heat exchanger:
![Name: P4P1Z37h.jpg
Views: 1802
Size: 133.5 KB](https://rennlist.com/forums/attachments/991/1344217d1683254620-ongoing-change-over-valve-issues-on-991-p4p1z37h.jpg)
COV under the transaxle (the one I couldn't get out - you can't see it in the pic, but the blue line is the atmosperic air line from the air box):
![Name: iVLOHn5h.jpg
Views: 1909
Size: 128.8 KB](https://rennlist.com/forums/attachments/991/1344218d1683254620-ongoing-change-over-valve-issues-on-991-ivlohn5h.jpg)
Heater COV, right side wheel well.
![Name: fCM9QShh.jpg
Views: 1901
Size: 148.6 KB](https://rennlist.com/forums/attachments/991/1344219d1683254620-ongoing-change-over-valve-issues-on-991-fcm9qshh.jpg)
Two COVs to the right of the engine. Pic blurry, but directly behind the right-side COV, there's another COV mount that's empty.
![Name: NatHF3mh.jpg
Views: 1710
Size: 152.6 KB](https://rennlist.com/forums/attachments/991/1344220d1683254620-ongoing-change-over-valve-issues-on-991-nathf3mh.jpg)
A more zoomed out pic of the same COVs, before I swapped them (they're black in this picture).
![Name: BsfmwlKh.jpg
Views: 1729
Size: 130.6 KB](https://rennlist.com/forums/attachments/991/1344221d1683254620-ongoing-change-over-valve-issues-on-991-bsfmwlkh.jpg)
I've had three COVs changed to the -F part in the past, so I bought 5 more to change myself (under the impression that my car has 8 total). I only was able to change three. I could only find 7 total on the car (a 2015 C2 with PDK and PSE). I had two on the airbox, one on the right side wheel well for the heater, two under the car (one by the transmission, one up above the driver's transaxle) and then two to the right of the engine. The stuff I've seen (Plenum's blog for instance) says my car should have 8, and that there should be three COVs on the right side of the engine. I can see a third COV mount behind the front two, but there's no COV there. I traced the vacuum line as well as I could and didn't find another. The mystery remains. So, obviously I didn't change that one. I also could not get to the one above the transaxle to change - I could see how to do it on a lift, but on jack stands, I couldn't work out how to do it.
So I buttoned the car back up with the three new valves, started it up, and the codes remain. My PORII says the codes (P1432 and P1433) are current (both listed as vacuum leaks) and clearing them does nothing as you'd expect.
Pulling the bumper, spoiler, air box and bottom covering is pretty easy, and putting it back together is easier than taking it apart. Getting the vaccum line connection off the COVs is a huge pain. Where I could get two hands in, I was able to work it off with a small screwdriver. In two cases, I just cut them off. The other two connectors are easy to get off, as is the electrical connection.
FWIW, my car had -C COVs from the factory. It was built on 7/30/14, or so a sticker under the bumper says.
Here are some pics that I happened to snap during the process.
Car up on jack stands & unbuttoned:
![Name: pSaK9djh.jpg
Views: 1682
Size: 174.3 KB](https://rennlist.com/forums/attachments/991/1343849d1683254620-ongoing-change-over-valve-issues-on-991-psak9djh.jpg)
Two COVs on the airbox:
![Name: eFvrX85h.jpg
Views: 1757
Size: 108.9 KB](https://rennlist.com/forums/attachments/991/1344216d1683254620-ongoing-change-over-valve-issues-on-991-efvrx85h.jpg)
COV on the underside of the car by the heat exchanger:
![Name: P4P1Z37h.jpg
Views: 1802
Size: 133.5 KB](https://rennlist.com/forums/attachments/991/1344217d1683254620-ongoing-change-over-valve-issues-on-991-p4p1z37h.jpg)
COV under the transaxle (the one I couldn't get out - you can't see it in the pic, but the blue line is the atmosperic air line from the air box):
![Name: iVLOHn5h.jpg
Views: 1909
Size: 128.8 KB](https://rennlist.com/forums/attachments/991/1344218d1683254620-ongoing-change-over-valve-issues-on-991-ivlohn5h.jpg)
Heater COV, right side wheel well.
![Name: fCM9QShh.jpg
Views: 1901
Size: 148.6 KB](https://rennlist.com/forums/attachments/991/1344219d1683254620-ongoing-change-over-valve-issues-on-991-fcm9qshh.jpg)
Two COVs to the right of the engine. Pic blurry, but directly behind the right-side COV, there's another COV mount that's empty.
![Name: NatHF3mh.jpg
Views: 1710
Size: 152.6 KB](https://rennlist.com/forums/attachments/991/1344220d1683254620-ongoing-change-over-valve-issues-on-991-nathf3mh.jpg)
A more zoomed out pic of the same COVs, before I swapped them (they're black in this picture).
![Name: BsfmwlKh.jpg
Views: 1729
Size: 130.6 KB](https://rennlist.com/forums/attachments/991/1344221d1683254620-ongoing-change-over-valve-issues-on-991-bsfmwlkh.jpg)
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ZL1 (07-31-2021)
#142
Drifting
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Are there certain years the 991.1's were effected or the entire range of them?
#143
Rennlist Member
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Originally Posted by C7toM2toGT4?
Are there certain years the 991.1's were effected or the entire range of them?
#144
Drifting
#145
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So I have confirmed that my '15 C2 with PDK and PSE has 7 COVs. I could only find 7, my service advisor claims there's 7 on my car, and the 991 STI (service technical intro) says my car has 7. There's a "tuning flap" in the 3.8L that the 3.4L doesn't have.
"The 3.8-liter engine also has a tuning flap in the intake manifold for improved charging, high torque at low to medium rpm and an even torque curve."
FWIW you can get the 911 STI document here (it's pretty useful): https://rennlist.com/forums/991/1050...s-997-too.html
"The 3.8-liter engine also has a tuning flap in the intake manifold for improved charging, high torque at low to medium rpm and an even torque curve."
FWIW you can get the 911 STI document here (it's pretty useful): https://rennlist.com/forums/991/1050...s-997-too.html
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vanlieremead (01-31-2021)
#146
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And a final update. Got the car back today after 10 days at the dealer. The bad part wasn't a COV. One of the valves for the PSE had failed. I also had them change the last COV above the transaxle. So now I have all -F COVs, which is nice, and I hope the Coolant System Failure saga is behind me for a good long while. It was another $1186 for the one new part, and the labor to replace it & replace the last -C COV for the -F that I gave them.
So I guess it is interesting to note that COV failure isn't the only cause of this dash fault - you can also have vacuum hoses come off, or you can have the actual valves that the COV control fail. My DME codes were P1432 and P1433 - "vacuum leak".
So I guess it is interesting to note that COV failure isn't the only cause of this dash fault - you can also have vacuum hoses come off, or you can have the actual valves that the COV control fail. My DME codes were P1432 and P1433 - "vacuum leak".
#147
Rennlist Member
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And a final update. Got the car back today after 10 days at the dealer. The bad part wasn't a COV. One of the valves for the PSE had failed. I also had them change the last COV above the transaxle. So now I have all -F COVs, which is nice, and I hope the Coolant System Failure saga is behind me for a good long while. It was another $1186 for the one new part, and the labor to replace it & replace the last -C COV for the -F that I gave them.
So I guess it is interesting to note that COV failure isn't the only cause of this dash fault - you can also have vacuum hoses come off, or you can have the actual valves that the COV control fail. My DME codes were P1432 and P1433 - "vacuum leak".
So I guess it is interesting to note that COV failure isn't the only cause of this dash fault - you can also have vacuum hoses come off, or you can have the actual valves that the COV control fail. My DME codes were P1432 and P1433 - "vacuum leak".
#148
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Well, the "cooling system failure" has won. I guess I'm taking it to the dealer, or a local indy.
I've had three COVs changed to the -F part in the past, so I bought 5 more to change myself (under the impression that my car has 8 total). I only was able to change three. I could only find 7 total on the car (a 2015 C2 with PDK and PSE). I had two on the airbox, one on the right side wheel well for the heater, two under the car (one by the transmission, one up above the driver's transaxle) and then two to the right of the engine. The stuff I've seen (Plenum's blog for instance) says my car should have 8, and that there should be three COVs on the right side of the engine. I can see a third COV mount behind the front two, but there's no COV there. I traced the vacuum line as well as I could and didn't find another. The mystery remains. So, obviously I didn't change that one. I also could not get to the one above the transaxle to change - I could see how to do it on a lift, but on jack stands, I couldn't work out how to do it.
So I buttoned the car back up with the three new valves, started it up, and the codes remain. My PORII says the codes (P1432 and P1433) are current (both listed as vacuum leaks) and clearing them does nothing as you'd expect.
Pulling the bumper, spoiler, air box and bottom covering is pretty easy, and putting it back together is easier than taking it apart. Getting the vaccum line connection off the COVs is a huge pain. Where I could get two hands in, I was able to work it off with a small screwdriver. In two cases, I just cut them off. The other two connectors are easy to get off, as is the electrical connection.
FWIW, my car had -C COVs from the factory. It was built on 7/30/14, or so a sticker under the bumper says.
Here are some pics that I happened to snap during the process.
Car up on jack stands & unbuttoned:
![](https://i.imgur.com/pSaK9djh.jpg)
Two COVs on the airbox:
![](https://i.imgur.com/eFvrX85h.jpg)
COV on the underside of the car by the heat exchanger:
![](https://i.imgur.com/P4P1Z37h.jpg)
COV under the transaxle (the one I couldn't get out - you can't see it in the pic, but the blue line is the atmosperic air line from the air box):
![](https://i.imgur.com/iVLOHn5h.jpg)
Heater COV, right side wheel well.
![](https://i.imgur.com/fCM9QShh.jpg)
Two COVs to the right of the engine. Pic blurry, but directly behind the right-side COV, there's another COV mount that's empty.
![](https://i.imgur.com/NatHF3mh.jpg)
A more zoomed out pic of the same COVs, before I swapped them (they're black in this picture).
![](https://i.imgur.com/BsfmwlKh.jpg)
I've had three COVs changed to the -F part in the past, so I bought 5 more to change myself (under the impression that my car has 8 total). I only was able to change three. I could only find 7 total on the car (a 2015 C2 with PDK and PSE). I had two on the airbox, one on the right side wheel well for the heater, two under the car (one by the transmission, one up above the driver's transaxle) and then two to the right of the engine. The stuff I've seen (Plenum's blog for instance) says my car should have 8, and that there should be three COVs on the right side of the engine. I can see a third COV mount behind the front two, but there's no COV there. I traced the vacuum line as well as I could and didn't find another. The mystery remains. So, obviously I didn't change that one. I also could not get to the one above the transaxle to change - I could see how to do it on a lift, but on jack stands, I couldn't work out how to do it.
So I buttoned the car back up with the three new valves, started it up, and the codes remain. My PORII says the codes (P1432 and P1433) are current (both listed as vacuum leaks) and clearing them does nothing as you'd expect.
Pulling the bumper, spoiler, air box and bottom covering is pretty easy, and putting it back together is easier than taking it apart. Getting the vaccum line connection off the COVs is a huge pain. Where I could get two hands in, I was able to work it off with a small screwdriver. In two cases, I just cut them off. The other two connectors are easy to get off, as is the electrical connection.
FWIW, my car had -C COVs from the factory. It was built on 7/30/14, or so a sticker under the bumper says.
Here are some pics that I happened to snap during the process.
Car up on jack stands & unbuttoned:
![](https://i.imgur.com/pSaK9djh.jpg)
Two COVs on the airbox:
![](https://i.imgur.com/eFvrX85h.jpg)
COV on the underside of the car by the heat exchanger:
![](https://i.imgur.com/P4P1Z37h.jpg)
COV under the transaxle (the one I couldn't get out - you can't see it in the pic, but the blue line is the atmosperic air line from the air box):
![](https://i.imgur.com/iVLOHn5h.jpg)
Heater COV, right side wheel well.
![](https://i.imgur.com/fCM9QShh.jpg)
Two COVs to the right of the engine. Pic blurry, but directly behind the right-side COV, there's another COV mount that's empty.
![](https://i.imgur.com/NatHF3mh.jpg)
A more zoomed out pic of the same COVs, before I swapped them (they're black in this picture).
![](https://i.imgur.com/BsfmwlKh.jpg)
I’m thinking this might be one of those rainy weekend projects.
#149
Rennlist Member
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Though, now a new question. Which of the pics above correlates to the Item 7 from Plenum’s blog; 7. Shut-Off Valve on Heat Exchanger for Gear Wheel Set Oil.
#150
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That one is on the bottom, but I don't remember if it's the easy to get to one, or the one buried under the transaxle...