Cabin air management bad (Cayman)

[zcacogp]

Guys, 

 

This is one mainly for the Cayman owners on here but I'd be very happy to have input from you Box chaps as well (who are greater in number). 

My 987.1 Cayman has the most awful cabin air flow management. It's hard to get the interior to the right temperature and particularly hard to control cabin moisture. I was reminded of the latter again when I drove it in pouring rain last night. It doesn't have climate control - just the basic air conditioning panel. 

I don't think it has a water leak into the cabin; it's a Cayman so hard-top and no folding roof seals to worry about. I have no damp carpets anywhere and it doesn't steam up if left out in the rain. However if you get into it with wet clothing (having walked to the car in the rain for instance) or even have a cup of coffee in the car then the cabin will fog up very quickly indeed and it's very hard to get rid of the condensation; I usually end up opening the window a little, which isn't great when it's raining. Turning on either of the demist buttons (windscreen fan one for the front, heater rear window for the back) reluctantly removes the moisture from the windows but if you turn the demist buttons off then it all reappears very quickly; it almost feels as if the damp air isn't allowed out of the car so the water settles back on the glass as soon as it can. 

I changed the cabin air filter when I bought the car (last summer). 

Do any other Cayman owners have this problem? (Or indeed any Boxster owners?) Does anyone know anything about how the air flows out of the cabin; it comes in under the front scuttle panel but I am not sure how it is meant to get out? A blocked air exit vent may explain my problem but I don't know where these are (and Porsche surely can't have designed the thing without any exit vents, surely?) 

An aside, but the cabin air flow management on my old 944 was utterly brilliant. I can't believe that Porsche have gone backwards in the intervening 20 years between the cars. Something must be wrong somewhere with my car. 

Thanks for your help. 

[Menoporsche]

I would always use aircon to get rid of condensation.  Either a filter or an airflow problem I guess.  Interested to see answers.

[Nobbie]

Is the air con working? Maybe it needs regassing, or front rads have perished. If it’s recirculating air and air con is bust then there’s now way for the moisture to escape.

[zcacogp]

@Menoporsche - what do you mean by "use aircon to get rid of condensation"? I've never had a car with air con before. I always have it on (the 'aircon off' button isn't pressed). Is this what you mean? 

@Nobbie - I changed the air con radiators in the nose about 3 months ago and had it re-gassed then. It blows cold when you ask it to so I think it's working. The condensation problem happened both before and after the radiator change. 

Thanks for your help chaps. 

[Menoporsche]

To my knowledge, aircon intentionally or otherwise includes an aspect of dehumidifying (this is why you'll see little trails of water under a car that has had its aircon running).  Knowing this I would put aircon on to dehumidify.  I don't know the details of the system and whether it would dehumidify when cooling and when heating or only when cooling.

[zcacogp]

Thanks, that's interesting. I'm not aware of there being a 'dehumidify' setting on the cabin heater controls anywhere. 

To only have dehumidify capability when cooling would seem odd; the biggest problems with cabin humidity are in the winter when you need the heating on. Working on this basis then there must be some dehumidify capability when the heating is on, which suggests that something is broken (or blocked.) 

[Lennym1984]

Don't all 987s have climate control? I just leave mine on "Auto" permanently and set the temperature I want. Make sure that you don't have the "Eco" mode on - this is basically AC off and so it won't dehumidify.

 

[zcacogp]

Nope, some have air conditioning but no climate control. I can set an adjuster to make things hotter or colder but there is no ability to set a desired temperature and for the system to maintain it, which is what the 'Climate Control' option gave you. 

No 'Eco' button on mine, although I do have an 'Air con off' button. 

You have this (i.e. climate control): 

I have this (i.e. no climate control): 

[Menoporsche]

Mine is also manual aircon, with fan and temp up/down but no temp input.

@zcacogp have a look around, google "aircon dehumidify in car" or similar and read around about how it works. I did but couldn't find one single article to link to, just various parts. It's not a setting, it's actually how the aircon works.

[Paul P]

A/C systems have a “dryer”. Does just that.  Takes moisture out of the air.  It’s a separate part to the a/c rads and can apparently “die” in an a/c system that’s for no gas/oil in it.  As meno says that’s why you get water puddles underneath. 
 

as to original question.  Are the flaps worki ok. That is when you press the various buttons for the air direction can you airflow where you expect it ?

also. Does the fan blow hard on full power ? 
 

my 1st 987 boxster had manual air con. If Found it hard to get a temp in the cabin that stayed constant.  Always found myself fiddling it.  
 

Latest 987 has climate.  Set temp press auto and forget it.  No fiddling.  
 

but both were able to keep a cabin clear although I have found that most cars (that are a/c equipped) need it on in very wet conditions to keep internal misting away

[Lennym1984]

4 minutes ago, zcacogp said:

Nope, some have air conditioning but no climate control. I can set an adjuster to make things hotter or colder but there is no ability to set a desired temperature and for the system to maintain it, which is what the 'Climate Control' option gave you. 

No 'Eco' button on mine, although I do have an 'Air con off' button. 

You have this (i.e. climate control): 

<img src=https://www.climaterepair.co.uk/wp-content/uploads/2017/03/Climate-960-338.png>

I have this (i.e. no climate control): 

<img src=https://rennlist.com/forums/attachments/parts-marketplace-old/1174027d1496968791-997-987-climate-control-assembly-like-new-img_9955.jpg>

Every day is a school day! They look so similar - I don't think I ever even noticed that they were different when looking at cars.

I haven't had manual AC in a car for many years but I remember it being a bit of a faff to find a temperature that worked.

In terms of your problems...

1. Try replacing the cabin filter - perhaps it is dirty/wet/loose

2. Was your AC drier replaced when you did the condensers? It's an easy job to do but the system will need to be evacuated first.

 

[zcacogp]

Menoporsche, thanks, I'll do some research. 

PaulP, that's interesting, thanks. So air-con dryers can die? I knew that such things existed and assumed that my car had one but didn't consider that it could either be changed or die. The previous owner ran it for some time without the air con working (the radiator was holed and he didn't change it) so your explanation sounds sensible. How hard is it to change the dryer? How expensive is the part? 

The controls all work as I'd expect; when you change the air direction on the buttons then you can hear the air flow changing in the cabin. You can get a fair breeze out of the fan if you turn it up but it's not spectacular (certainly not compared to the old 944 where the fan would have been enough to get a fairly large sailing yacht underway ... ) 

[zcacogp]

1 minute ago, Lennym1984 said:

Every day is a school day! They look so similar - I don't think I ever even noticed that they were different when looking at cars.

I haven't had manual AC in a car for many years but I remember it being a bit of a faff to find a temperature that worked.

In terms of your problems...

1. Try replacing the cabin filter - perhaps it is dirty/wet/loose

2. Was your AC drier replaced when you did the condensers? It's an easy job to do but the system will need to be evacuated first.

 

Cabin filter was changed and is (as far as I am aware) OK. 

Tell me more about changing the dryer ... no it wasn't changed when I did the condensers. 

[Lennym1984]

It's a metal cylinder up near the battery (passenger side I think). They are *supposed* to be changed whenever you open up the system (ie. changing condensers) but I have skipped this step before (on my wife's car) and it was fine. I'm not convinced that is your problem but it is good practice to replace them when changing components.

My only other thought is that you should check all of the carpets to make sure there isn't a leak (front drain holes for example). A damp car would create condensation issues obviously.

All of that said, I do find the Cayman cabin to be pretty airtight so that probably doesn't help.

[zcacogp]

Lenny, 

Thanks. A bit of googling suggests that they cost around £15, which is affordable .... the annoying thing is that I will need to have the gas taken out of my system to change the dryer and then have it re-gassed. 

A question however; what does it do? Does it dry out the air conditioning fluid itself? Surely not; the air conditioning system is sealed so how would water get into it (unless a seal somewhere has been compromised, in which case a little bit of moisture may have got in). I certainly can't see how moisture from the cabin could get into the air conditioning fluid itself, but I may be misunderstanding the function of the dryer.  

I don't think there is a cabin leak; there is no sign of one. The carpets are dry, the car doesn't steam up when left outside in the rain, it doesn't feel damp inside. It's just that the airflow in the cabin is generally poor and condensation is a big problem when you introduce something damp to the cabin. This will be exacerbated by the fact that the cabin air volume in a 987 will be quite small but it's a proper nuisance. 

[Lennym1984]

If you google how an AC system works (I'm not being lazy, I just think it'll provide a clearer explanation) you will see what the purpose of the dryer is. They can look a bit manky inside over time...

 

[Nobbie]

I think the dryer is a red herring here, it is part of a closed system holding the refrigerant and filters and removes moisture from it. It won’t affect the humidity in the cabin and if the air con is pumping out cold air then it’s not blocked. I wonder if the air con water vent is blocked. This is what takes the excess water from inside the cabin via the AC system and drops it on the ground beneath the car. If you leave the car running with moisture in the cabin it should drip onto the floor beneath the car.

[zcacogp]

Nobbie, 

Thanks. Where is the air con water vent? 

[Happy Days]

35 minutes ago, zcacogp said:

Nobbie, 

Thanks. Where is the air con water vent? 

About level with the rear of the front axle you often see a puddle - the vent will be visible if you scoot underneath or (if you're a bit lazy) use a mirror.

[zcacogp]

HD - thanks. I'll be under the car this weekend as I'm meant to be changing the tie rods and front brakes. I'll have a squiz then. Is it central to the car? Is it fairly easy to see? 

[Happy Days]

11 minutes ago, zcacogp said:

HD - thanks. I'll be under the car this weekend as I'm meant to be changing the tie rods and front brakes. I'll have a squiz then. Is it central to the car? Is it fairly easy to see? 

No idea as I am totally lazy... 🙂

FWIW, my car steams up badly as well (718) but the boost demister does clear it. I get paranoid about leaking drains but at this time of year, your feet are wet and will transfer the dampness to the cabin, your coat is wet etc etc. Some people chatting a few days on here about silica gel bags that they use to contain moisture - maybe dig that thread up. I would do it for you, but as I said earlier, I'm lazy 😉

[zcacogp]

Ah - a fellow idle hound. Let's be friends! 

[Menoporsche]

...ooh look, more dog jokes...

[bandit_287]

My 981 steams up really badly too, a lot worse than my previous 987.2. 

[zcacogp]

@bandit_287 - interesting. Any idea why? 

FWIW, I was under my 987 today and looked for the air conditioning drain point and couldn't see anything in the relevant area. Undertray was off: fuel tank, coolant pipes, ARB's and everything else was there but I couldn't see any sign of an air con drain. I presume it would be in line with the dashboard as the cooling matrix would be in the HVAC somewhere in the dash (i.e. in line with the back of the front axle as Happy Days said.)