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New 997 owner. AC works, then cuts out? Gas topped up.

C11BRA

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30 Mar 2015
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Hello 997 guys. I've been kicked out of the 996 forum after selling my 98 C2.
I had it for 7 years and many 996 forum guys will have seen many of my modifications (some not universally liked).

Anyway. I've treated myself to a 2006 997 C2. Ooooh. I like it.

It's had quite a nice amount of upgrades but one of these was an AC compressor bypass. Basically, a non AC belt was fitted at the same time as an IPD plenum & the larger throttle housing. I'm guessing to save half a horse power.

My first job was to fit the AC sized belt. I added some DIY gas to check for immediate leaks from the usual suspects, condensers, pipes & joints. The gas held & the AC blew cold. Great.....I'll just keep an eye on it and in a week or so I'll get it all vacced out & re-gassed properly.

We jumped in the car and went to the BH Monday Ace cafe meet. About half way there (approx 10 miles) we hit a bump in the road & the AC started blowing warm. Could have been coincidence. After about 5 minutes, it started blowing cold again. Hmmmmm.

After a lovely Ace meet, we drove home with AC......initially. About half way, it blew warm again. No bump this time. And this time, it didn't come back on.

I plan to get the proper re-gas done on Thursday but just wondered if there is a common fault that might fit my symptoms.

Any ideas will be appreciated.
 
Sounds like it was on the verge of making up its mind over whether it was holding pressure, if it's leaking out which it probably is then it's probably hit the minimum before shutting itself off for safety reasons.

It's either that or Bore Scoring, and I know very little about that as well !
 
I'll report back on Thursday. Tbh. I can't wait to just drive it again.

New V5 should arrive this week so I'm taxed, reg transferred, insured and legal to drive.

Big welsh mountain road drive planned foe November. Must get the AC working for then.
 
The AC pump clutch could be disengaging intermittently when running. If this is the case either the clutch is faulty or there's a dodgy connection in the harness somewhere.
 
Good luck, come November in Wales you'll not be needing air con....


I'm supposed to be going Next weekend and doing the Triangle, Brecon and a few other Routes.
 
Sorry to not see you in the 996 forum any more .


Welcome to the 997 forum where i will see you :D


Gas will slowly leak out over a period of time .. a bump in the road won't make it stop working and then work again due to the amount of gas in the system .

these are the same as all porsches .. as the gas starts to get low you will get noises in the cabin which go when you turn off the a/c ... easy check to see if the system is low on gas basically .

Whilst i don't have an answer im leaning towards a temp sensor messing around .. electrics do respond to bumps and will stop / start in their operation ... so compressor , sensors control unit etc etc ..

A tester on these and you can soon see if an interior temp sensor is reading incorrect... you can also check fault codes .. 997 is a wee bit more advanced than a 996 .. which is good .. and not so good as there's more things that can go wrong .

Curious the system had been bypassed through .. there's a reason for that and i dont feel its horsepower .
 
Sounds to me like it could be an intermittent electric fault. Next time it goes warm run round the back and see that the electro-magnetic clutch is engaged.
 
I had a similar problem with my a/c blowing cold then warm ,had it re- gassed blew cold for about a week then warm again..............anyway the problem was the a/c pipes. where they are fixed to the body the pipes run through fixing clamps which are quite big and they rust ,so by removing the clamp you can see the problem (a small pin hole) so metal fix and a jubilee clip done the job

Just out of interest to renew the pipes is an engine out job

Hope that helps
 
C4Silver said:
Good luck, come November in Wales you'll not be needing air con....


I'm supposed to be going Next weekend and doing the Triangle, Brecon and a few other Routes.

Let me know if you find any must do roads. I'm still researching my route.

BTW. My wife needs AC. Even when it's snowing!!??
 
Thanks for all your replies. I'll be ready in my next trip to jump out with a meter to check compressor supply feed.
 
deMort said:
Sorry to not see you in the 996 forum any more .


Welcome to the 997 forum where i will see you :D


Gas will slowly leak out over a period of time .. a bump in the road won't make it stop working and then work again due to the amount of gas in the system .

these are the same as all porsches .. as the gas starts to get low you will get noises in the cabin which go when you turn off the a/c ... easy check to see if the system is low on gas basically .

Whilst i don't have an answer im leaning towards a temp sensor messing around .. electrics do respond to bumps and will stop / start in their operation ... so compressor , sensors control unit etc etc ..

A tester on these and you can soon see if an interior temp sensor is reading incorrect... you can also check fault codes .. 997 is a wee bit more advanced than a 996 .. which is good .. and not so good as there's more things that can go wrong .

Curious the system had been bypassed through .. there's a reason for that and i dont feel its horsepower .

Yeah. I'm slightly suspicious about the compressor bypass. But it was done in conjunction with engine upgrades so I'm hoping it was just a badly advised performance move.

I have an Autel diag tool. Do you think I'll be able to see sensor values? After the re-gas, I'll road test & monitor.

Is there a wiring diagram of the 2006 997 AC system available anywhere? I quite like understanding where all the sensors are & relays etc.

I MUST GET THE A/C RELIABLE!!!
 
Could also be your expansion valve playing up. Might be a bit sticky if the system hasn't been used for some time. Had a similar problem with my Dad's Saab years ago.

I suggest you leave the system on full time when using the car to get everything well lubricated and operational.
 
Just had a quick look around the AC pipes etc to see if there was any sweating etc. Thought I'd check the AC clutch connection. With hardly any force, the connector came apart. And inside (the male spade) was pretty grubby looking. Hmm. Why would Porsche still use this same 1980's style connector when pretty much all the others are submarine spec!!!




So. I've cleaned the male spade, given the female a slight nip with a pair of long noses and fitted back together with a coating of special connector grease.
Thursdays road test will reveal any improvement or not.
 

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