10 captured repliesPartial discussion capture · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH991 Cooling System Fault - Page 1 - 911/Carrera GT - PistonHeads UK
Leading reported evidence
Replace burst coolant pipe at the back of the car
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
Burst coolant pipe at the back of the car which was replaced under warranty plus coolant pump.
991 Cooling System Fault - Page 1 - 911/Carrera GT - PistonHeads UK
Read full discussion summary
Leading evidence: 'Replace burst coolant pipe at the back of the car' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'changeover valve' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Repair get the warranty company' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
I thought it was probably the changeover valve but turned out to be a failed thermostat.
991 Cooling System Fault - Page 1 - 911/Carrera GT - PistonHeads UK
failed thermostat
Suggestion or failed attempt
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
I thought it was probably the changeover valve but turned out to be a failed thermostat.
991 Cooling System Fault - Page 1 - 911/Carrera GT - PistonHeads UK
Outcome qualification: Negation, uncertainty or missing explicit repair resolution overrides the raw extraction signal.
Repair get the warranty company
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
If it’s under warranty don’t worry about the cost of repair, get the warranty company to investigate the fault.
991 Cooling System Fault - Page 1 - 911/Carrera GT - PistonHeads UK
Replace valve
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
991 Cooling System Fault - Page 1 - 911/Carrera GT - PistonHeads UK
Outcome qualification: Negation, uncertainty or missing explicit repair resolution overrides the raw extraction signal.
Coverage and how to read this overview
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
10 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
PistonHeads: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 1 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T155324Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Rats. My nice new (to me) 991.1 manual has developed an amber warning:
It’s under warranty but curious if anyone else has had this, what it was and what the cost was of repair.
Thanks!
If it’s under warranty don’t worry about the cost of repair, get the warranty company to investigate the fault. If the cost of repair exceeds the warranty and you’ve just bought the car reject it.
Edited by Huskyman on Thursday 13th January 21:03
Edited by Huskyman on Thursday 13th January 21:04
67Dino said:
Rats. My nice new (to me) 991.1 manual has developed an amber warning:
It’s under warranty but curious if anyone else has had this, what it was and what the cost was of repair.
Thanks!
yes, happened to me. it was a change over valve. most of the time is that.
the problem is that there are 12 of them. so few months after changing the one for the cooling system i lost the heating , in december of course
anyway, the most important thing is that you keep an eye to the cooling refrigerant temperature, which should stay at 90. not the oil.
and get porsche to change the valve
Just updating the thread in case anyone searches.
I watched my temp gauges and oil and water stayed politely at 105c and 90c on my journey to the dealer so no problems there.
Had it looked at and turns out it was a change over valve and transmission cooler control valve diaphram leaking. These need replacing which in turn requires the cooling system to be drained. The cost is less than £100 of parts but 3.5 hours of labour. At a Porsche dealer this totals about £650+Vat, but no doubt would be considerably less at an Indy.
As previous posters have said, the dealer said there are about a dozen of these valves in a 991, a complexity in part due to the radiators being at the front and the engine at the back. He said it’s highly likely one or more of them will fail on any car, a weak point in the model.
Just one those things, and thankfully in my case, largely covered under warrantee.
Edited by 67Dino on Saturday 5th February 22:59
Had the same message on my 991c2s
Burst coolant pipe at the back of the car which was replaced under warranty plus coolant pump. Which i had no warning for but saw dripping from rear of car so got Porsche mid-Sussex to replace. And then 24 hours after getting the car back, vacuum valve went and it had to be roadside assisted back to Porsche again. Porsche charged warranty £2500 in all for a pipe, pump and valve.
Ouch, that’s a bit painful. Can see these bills could easily put people off getting a 991. Shame as I’m absolutely loving mine, and think it’s the best 911 I’ve had (having previously owned a 964, 996 C2, 996 C4 and 997).
Funny my car’s booked in for the same thing. It’s at least one change over valve too. I also had an engine fault on the left cylinder bank due to one of these a few years ago.
Seems to be the only real weak point of the 991.
