Heater noise?!???

Not sure if anyone has any experience or ideas. There's a noise in the cabin. I thought it was the fan motor now I aren't too sure!! So engine off, fan on and all's good. Start the car and there's a feint noise. Drive an hour and idle there is a bit of racket! Turn the ac button and it stops, turn the fan all the way off and it stops. Outside the car I can hear the fans, the passenger side seems louder. At the rear I can't hear much over the top gear exhaust!!! Ac has been gassed, condensers replaced. No leaks and all functioning. Could the passengers fan be off a bit and it resonates back into the cabin?!? It's annoying but hardly critical?!? It doesn't seem to be a consistent noise, definitely worse when the engines warmed up or after a drive

My AC makes a noise when it's low on Gas.

The temperature sensor has a fan in it too which can get rather noisy.... Put your ear close to that on the far left side of the dash behind a tiny circular grill to try to rule hat out too

Ah right, the noise does seem to be omitted from the passengers side. Outside the car I can hear a strange noise near the bulkhead area?!? I'll have a listen to the temp fan, I love the car, well cars in general and don't ever mind buying parts but obviously I don't want to replace everything if it's not necessary!! I've already bought the blower motor but it was only £80 so I'll fit that anyway so it's new and shiny!!!

If the noise goes when the A/C is turned off then its caused by low gass in the system and needs recharging / leak found and fixed . noise will be passenger side or under the bonnet and passenger side as thats where the expansion valve is for the a/c .. low gass kinda causes the gass to condense in the wrong place .. not correct i know for the purists but trying to explain here

Thanks for the replies, had a read about some stuff and also applied some logical thinking! Noise goes when AC button is off or fans shut down so its AC related which is a leak and low gas or the compressor. It was recharged and held whilst on the machine but they did put dye in so we should be able to see the leak. I'm assuming probably a small hole in a pipe letting a small bit out but over the six weeks or so its dropped to a point where air is present in the pipe not just the gas and its noisy. Id guess like heating pipes make a noise after its drained down as air is present and not just water. I guess seen as its like Artic conditions, turn the AC off and if I do use the car don't have it on until i've fixed the cause. Its quite bearable without AC at the moment!!!

its the lower pressure that causes the gass to condense sooner so not where it should which is the expansion valve imho . Correct amount of gass and a higher pressure . 6 weeks is a slow leak and very common . Dont really matter though .. it had dye installed so ultraviolet light check on the condensors , pipes etc and see what can be found. To give you an idea .. on a service i road test a car .. i set the a/c on , temp at 19.5 and a fan speed of 3 bars .. if i hear a noise which goes with the a/c turned off then i flag up an a/c service with a possible leak to be investigated Its that common .

I've put two condensers on, new o rings, new drier, new o rings and all torqued as per the manual so I'm guessing a pipe. This has been a noise for a while and I thought it was the condenser on the near side so put a pair on, obviously it's a pipe! They seem reasonably priced though 😳

Yes but they're Bugg3rs to fit! Mine had the classic leak in front of the RHR jacking point and 9e managed to fix it. Pipe replacement requires a lot of dismantling apparently.

Yeah reading up it seems like these are the favourite ones to fail!! I will get a uv light on it and have a look and make an assessment. They seem to join in the inner arch area somewhere so bumper, wheel, arch liner, front boot thing plastics all want removing so yeah a pain in the backside. Let's hope it's an o ring on the back!!! £2 and ten minutes?!?

The a/c pipes o/s/r and just in front of the wheel under the panel are the second most common place to fail with condensors being the first . It is indeed an o ring .. will it come undone .. ermm .. you might get lucky and it does , it might be the seal . More than likely it wont come undone , it wont be the seal and you will need to replace the pipes from the o/s/f wheel arch area to that point . I know as ive done so many of these ive lost count .. i can give you instructions from memory on how to do it im afraid . Steel bolts into an ally connection is Not a good mix .. ive seen a mechanic try and heat them up .. the resulting gass from boiling pag oil even got me scared .. something about the gass / oil and mustard gass when it gets hot :dont know: cant say but it wasnt pleasent . UV light to confirm first though . Bad news from me again .. its getting to be a habbit

When the weather stops been ridiculous I'll have a look with a uv lamp. The guys at the garage where it was gassed said I can borrow it so we'll see from there. Ally and steel is always fun!! Try merc vito injector bolts!!! M5 fine thread steel stretch bolts into an ally head!! One bolt holding the injector in and one chance to get it right before it's off to an engineering shop?!

i feel your pain young man .. steel / ally doesn't mix but we keep seeing it from caliper bolts to a/c pipes .. fine when the cars were newer .. not so much these days . Fingers crossed they come undone .. it does happen trust me .. but i am always shocked the few times that it does .

Yeah I'm no mechanic, handily I have a friend with a garage and mot station, one who owns a body shop and a friend who's a motorcycle race mechanic !! They've always taught me and are on hand when I'm stuck?!? I like to twirl the spanner's where I can but I know my limitations !! None of them know Porsche's is the big downside. I appreciate all the advice, even if it's not the answer I want to hear!!