DB9 2005 Coupe Aircon behaviour

[MFaiz]

Been experiencing a strange issue with my DB9 climate control.. The aircon works fine and is cool enough normally with the air being internally circulated. The ambient temperature in Malaysia is about 36C and the aircon is set to 19C.

However, when I take the car for a long run, say about an hour at speed, and then get stuck in traffic in the city, the whole cabin suddenly feels a lot warmer. I usually have to drop the temperature and max out the aircon for a while before it starts to pump cool air but it never quite gets cold again. I usually have to stop the car for a while, restart it and then the aircon works normally.

I saw a post on another forum from a user in Dubai, who seems to have the same issue but no explanation was given.

Has anyone experienced this before? Is there some way that the hot air around the engine can get into the aircon system? Is there something that needs doing to an Aston to acclimatise it to work in hot countries?

Thanks in advance.

[V12Vantage]

Have you ever had the system regassed?
They do tend to lose a bit of gas over time.

[Robbontherock]

Could be that the heat exchanger is getting iced up, I've seen office aircon systems do that. Need to switch them off, then the heat exchanger warms up and thaws out the exchanger.

Worth checking out the exchanger and ensuring that the air flow is not partially blocked or something.

Cheers
Andy

[MFaiz]

Thanks for the advice. Is there anyway of knowing how much gas is in the system?

Re the icing up, will ask my mechanic to check but would seem surprising if it did as the ambient temperature is so high.

[kalibre46]

When the system is regassed they will also purge it of the existing gas and oil so that you know how much was in there. My DB9 aircon was also being unreliable. Mine had 149grams of gas and 0grams of oil in it apparently. After regas this was 850 and 10 respectively. Aircon is ice cold 100% of the time now.

Doesn't cost a lot either.

[mikey k]

Robbontherock said:

Could be that the heat exchanger is getting iced up, I've seen office aircon systems do that. Need to switch them off, then the heat exchanger warms up and thaws out the exchanger.

Worth checking out the exchanger and ensuring that the air flow is not partially blocked or something.

Cheers
Andy

This is can also happen if the unit is low on gas or the expansion valve is set too low
It is the same for most refridgerant systems

[marko33]

What year is the car? You should be having it regassed every 3 years especially in a hot climate like yours, once you've been for a drive and then get back into traffic you have got all this extra heat from the engine and exhaust heating the cabin. If your a/c has only 60% charge then it will struggle to cool the car. Get it regassed by a SPECIALIST, it should be fine then and if there is a problem with anything like cooling fans then the SPECIALIST should tell you.

[Robbontherock]

mikey k said:

This is can also happen if the unit is low on gas or the expansion valve is set too low
It is the same for most refridgerant systems

Yeah, it's been many years since I worked on a air con unit it's all coming flooding back now.........

Cheers
Andy

[MFaiz]

The car is a 2005 model and I suspect the dealer hadnt checked the gas levels before delivery to me. Will certainly do the gas check as a first step. Thanks

[MFaiz]

Quick update, car still being tested but came across an article in 2005 saying this of the DB9. "Our final complaint was about the air conditioning which struggled to provide a comfortable ambience in the admittedly hot conditions of our test and then would temporarily quit when the engine temperature began to climb."

Looks like there may be a design issue with the earlier DB9 aircons.

[MFaiz]

Well, two months of tinkering and it seems that I had a leaky aircon system so lots of things have been replaced and it now runs smoothly.

It still isnt the coldest car but it is now bearable! I dont think Astons are designed for hot weather countries.

[jeremydb9]

How dare you say that - England is 32 degrees today. Granted it will probably snow tomorrow!

My AC today is Ok but only OK. The car is cold but I like it freezing. So maybe I need a top up too.

[F1 NDW]

Best Air con I ever had was in a Merc, so things can only get better for Aston!

[MFaiz]

A year and a bit on, the Aircon system is still an issue!

When the car runs at first no problem. When the car runs for a while, I can feel the engine heat coming through the air vent but only on the middle vent driver side, the other vent still pumps cool air.

Am considering getting my mechanic to open up the engine area and wrap all the aircon tubes with exhaust heat tapes to insulate them better.

Has anyone tried this or can force problems?

[ScottB]

I had very similar symptoms with my Vanquish and the issue was with the aircon cooling water valve.

Bamford Rose fixed this so it may be worth contacting them for some advice.