[Racefox]

Hi all - first time owner of a 718 Cayman S here, which I bought 3 weeks ago. Absolutely thrilled so far, already added 1,500 miles to it since purchase.

Question to the forum: went for a ride yesterday in upstate NY, Harriman State Park and then north on 9W, which is basically a long uphill drive. Very curvy, was operating in manual PDK throughout, pushing the engine quite hard (average 4-5k rpm, with occasional acceleration beyond that) - so definitely sporty drive but honestly not anywhere near the performance a more experienced driver would command from a car.

Temperature yesterday was around 90 Fahrenheit. After around 10 mins of heavy load the A/C climate suddenly turned off and wouldn't turn out any more cold air, up to the point where I would start sweating. Tried to fiddle around with the buttons, turning A/C on manually, auto sync, etc - to no avail. Only after I stopped for about a minute would the A/C come on again. Is this "normal behavior"?

The manual states that "the cooling function can switch off briefly to ensure sufficient engine cooling when the engine is operating under extreme load" - but again, I'm not an experienced / race driver and would think that I've operated the car well below its max capabilities.

Any thoughts on this / has this happened to you guys before? Or should I take it to the dealer to check? (2017 model, 11.5k miles, all services done).

PS: on the same drive I noticed that the oil pressure would regularly hit 70psi under acceleration - hitting the red area on the right. Hadn't noticed that before, but might be entirely normal. Is this something to monitor?

Thanks all, have a great Sunday!

 

[DriveInHouston]

Were you on Normal, or Sport mode?

 

[Racefox]

Sport mode throughout

 

[DriveInHouston]

Well, I have a Cayman S and have been pushing it, to the extend of my ability, in similar (even the same 9W on the way to Lake Placid, last fall). Even here in Texas, I never had a problem.

Did you see any abnormal coolant/oil temperatures?

 

[Racefox]

Interesting - oil and coolant temperatures all looked fine. It was really just the oil pressure that looked pretty high at times, but all other indicators well within the normal range of operations. Like I said, took about a minute of standing and then turning the A/C on / off manually to get it back working. This occurred twice over the course of an hour. No issues at all once I hit the highway back to NYC and driving at moderate pace.

 

[718 CS]

Interesting - oil and coolant temperatures all looked fine. It was really just the oil pressure that looked pretty high at times, but all other indicators well within the normal range of operations. Like I said, took about a minute of standing and then turning the A/C on / off manually to get it back working. This occurred twice over the course of an hour. No issues at all once I hit the highway back to NYC and driving at moderate pace.

Possible ice buildup from humidity? Sensor turns off A/C until it melts to protect against physical damage.

 

[Barryng]

Possible ice buildup from humidity? Sensor turns off A/C until it melts to protect against physical damage.

Ice buildup almost always mean the system is low on refrigerant as, no matter how high the humidity, the expansion valve, or equivalent, is designed to keep the evaporator surface temperature above freezing. At least in my experience, any response to ice buildup only disengages the compressor, it does not turn off the evaporator fan. Ice buildup is not normal and means something needs fixing (most likely a refrigerant leak or possibly a bad expansion valve).

 

[MikePhDPE]

every vehicle disengages the clutch to the a/c compressor when either the RPMs pass a certain point or when it detects a full throttle situation.

 

[Barryng]

every vehicle disengages the clutch to the a/c compressor when either the RPMs pass a certain point or when it detects a full throttle situation.

Very true! However, I interpreted the original post as saying the entire system just shut down, not just the compressor being disengaged. I dont know for sure but I would not expect only "average 4-5k rpm, with occasional acceleration beyond that" to cause the compressor to disengage and any brief full throttle applications would probably not be very noticeable.

 

[MikePhDPE]

@Barryng on all my previous cars whenever i'd get on it hard the A/C would stop blowing cold air because the compressor shuts down.

 

[Racefox]

Super helpful, thanks guys - will continue to monitor and see if I can replicate. To clarify, only the cold air shut down. There was still some (warm) air coming out of the vents (albeit at very low fan speed despite setting on A/C Max).

 

[GregW]

A/C Max is a 'special' setting, that I rarely use—even in +42°C, and never when pushing it.
I don't ever remember a cooling shut down. I don't have my manual to hand but I'd be checking that.

 

[Barryng]

A/C Max is a 'special' setting, that I rarely use—even in +42°C, and never when pushing it.
I don't ever remember a cooling shut down. I don't have my manual to hand but I'd be checking that.

I am curious why you rarely use it. A/C max sets evaporator fan on max speed, full recirc of cabin air with no hot humid exterior air sucked in, and mixes no intentionally heated air in with the cooled/dehumidified air, all to achieve maximum cooling. I do not think the max setting does anything more nor can I think of what it could do more. On hot days I regularly use this setting and have done so since the first air conditioned car in my family, a new 1964 Buick Electra. Back in 1980 I spent time in the southern Omani desert where temps regularly hit 42C/107F and always had the A/C on max. Here in south Florida I also frequently use this setting. It made no sense to me not to use this design feature of the machinery and it did establish cooler/drier cabin temps. For racing the compressor load (primarily) plus the fan electrical load does rob energy from the engine but I cant think of any reason if not racing, other than fuel economy, not to use the A/C in any mode so curious why you do not use max.

On a really hot day running the A/C in any mode makes it harder on the engine cooling system since the condenser usually sits right in front of the radiator. However, I have never seen a well maintained or new vehicle have a problem with engine cooling because the A/C is on although certainly older and poorly maintained cars might have a problem.

 

[jimmuller]

I am curious why you rarely use it. A/C max sets evaporator fan on max speed, full recirc of cabin air with no hot humid exterior air sucked in, and mixes no intentionally heated air in with the cooled/dehumidified air, all to achieve maximum cooling.

Thanks for the description of things A/C Max does. I don't recall seeing that before. It makes sense though.

To provide at least one answer to your question, consider this conversation: "The A/C sure is loud." "What?" "The A/C sure is loud." "I can't hear you, the A/C is so loud."

Of course, we live in a cool clime but we rarely need A/C Max. Just plain ol' A/C can make the car pretty frigid.

 

[Barryng]

To provide at least one answer to your question, consider this conversation: "The A/C sure is loud." "What?" "The A/C sure is loud." "I can't hear you, the A/C is so loud."

I certainly agree with that. I frequently notice in both my Boxster and previous Z4 the fan programs for the auto A/C systems can be too aggressive sometimes and the fan noise becomes annoying. HOWEVER, if I have a choice between fan noise or heat/humidity, I will always wimp out and choose fan noise.

Also, as just a point of trivia, faster air flow (or stated as a geek - higher mass flow rate) will always provide better cooling. But, if I remember correctly, a lower air flow will provide better de-humidification, which to me, is more important than cooling.

 

[jns211]

Hi all - first time owner of a 718 Cayman S here, which I bought 3 weeks ago. Absolutely thrilled so far, already added 1,500 miles to it since purchase.

Question to the forum: went for a ride yesterday in upstate NY, Harriman State Park and then north on 9W, which is basically a long uphill drive. Very curvy, was operating in manual PDK throughout, pushing the engine quite hard (average 4-5k rpm, with occasional acceleration beyond that) - so definitely sporty drive but honestly not anywhere near the performance a more experienced driver would command from a car.

Temperature yesterday was around 90 Fahrenheit. After around 10 mins of heavy load the A/C climate suddenly turned off and wouldn't turn out any more cold air, up to the point where I would start sweating. Tried to fiddle around with the buttons, turning A/C on manually, auto sync, etc - to no avail. Only after I stopped for about a minute would the A/C come on again. Is this "normal behavior"?

The manual states that "the cooling function can switch off briefly to ensure sufficient engine cooling when the engine is operating under extreme load" - but again, I'm not an experienced / race driver and would think that I've operated the car well below its max capabilities.

Any thoughts on this / has this happened to you guys before? Or should I take it to the dealer to check? (2017 model, 11.5k miles, all services done).

PS: on the same drive I noticed that the oil pressure would regularly hit 70psi under acceleration - hitting the red area on the right. Hadn't noticed that before, but might be entirely normal. Is this something to monitor?

Thanks all, have a great Sunday!

Had a similar issue with my Boxster. After about 1.5 years of ownership, the AC started to intermittently blow air or not blow air.

The dealer replaced the blower motor and voltage regulator under warranty without any push-back or cost to me. I'd say this is probably an issue that's already on the radar for service departments.

Sounds like you are under warranty still, so take it to the dealer and get it fixed for free. The AC should always work in your car.

 

[GregW]

<snips>I am curious why you rarely use it.

When I climb into a HOT car that's been sitting in the sun I use it. However once the cabin is at a comfortable temperature I turn it onto "auto" to let that temperature be maintained.
Note—summer here is desert-dry with almost no humidity at all, so dehumidifying and cooling is never an issue.

 

[dkmajm]

Where I live in tropical far North Queensland we have 2 seasons; hot
And bloody hot...


Sent from my iPad using Tapatalk

 

[Viffermike]

@Racefox First: Welcome to the forum!

What you describe is a known issue with early 718s, to the point where there was reportedly a Service Bulletin about it within Porsche. The solution was software/ECU-based, IIRC. Since your car is brand new (right?), however, it shouldn't be exhibiting that behavior -- BUT, to me, that's a clue that it might simply be related to the original issue that was corrected via revised software. We all know that a software 'bug' isn't always squashed the first time you swat at it ...

Bottom line: Take it to the dealer, and do what you can to either record when it happens or provide as detailed a description as possible about when it happens (i.e., under what conditions).

 

[Racefox]

@Racefox First: Welcome to the forum!

What you describe is a known issue with early 718s, to the point where there was reportedly a Service Bulletin about it within Porsche. The solution was software/ECU-based, IIRC. Since your car is brand new (right?), however, it shouldn't be exhibiting that behavior -- BUT, to me, that's a clue that it might simply be related to the original issue that was corrected via revised software. We all know that a software 'bug' isn't always squashed the first time you swat at it ...

Bottom line: Take it to the dealer, and do what you can to either record when it happens or provide as detailed a description as possible about when it happens (i.e., under what conditions).

Thanks, Viffermike. Great to know re: the early model software glitch. I should have mentioned that this is a 2017 model, so could definitely be caused by this. I’ll check with the dealer. Wasn’t able to replicate the issue over the past week.

While this may not fit right in here... I’m curious what other “bugs” early models suffered? Anything I should look out for or get fixed proactively?

Thanks again