Aircon delay when hot!

[Swotty]

W215 Cl600

Hi,

It gets very hot out here and, when returning to the car after e.g lunch, the aircon doesn't come on for between 5-10 minutes ....... just when you need it! It's fine when starting first thing, in the garage, which is open-fronted but covered from the sun.

Does this sound like a sensor issue, or am I just not yet getting the hang of the complexity of these cars?

Any thoughts, please? The missus loves the car but is getting fed up of not having aircon when most needed.

Thanks,

Stuart

 

[GordonTarling]

The aircon will take a few minutes to start blowing cold if the car has been left sitting in the sun. I've found that the best thing is to crack a couple of windows open for a couple of minutes, which seems to help purge the hot air. Close the windows again as soon as you feel cool air from the vents.

 

[martyz]

When was it last re-gassed? could be low.

 

[Swotty]

Thanks both.

Aircon was regassed last year and, when it gets going, is fine.

Have tried opening windows/sunroof but to no avail. I'm thinking a luxury car like this shouldn't have this problem and wonder if there's some kind of temperature sensor malfunctioning?

Stuart

 

[John]

I've had something similar in the past on mine.

A couple of times on the very hottest days it will seem to take an age to start blowing cold air.

Once it finally gets going it gets ice cold so it is not charged.

Almost like the compressor was taking a quick nap when it was supposed to start!

Every other time - starts straight away and is fine.

I put it down to dodgy electrics caused by my duff alternator as it has not done it since (replaced at the turn of the year).

 

[Swotty]

Thanks John,

Yes, that's the problem. I'm not aware of an alternator issue but will keep an eye open for other signs.

Stuart

 

[John]

Thanks John,

Yes, that's the problem. I'm not aware of an alternator issue but will keep an eye open for other signs.

Stuart

Mine was alternator but duff batteries could be doing it as well (I know my batteries are good though so I could rule them out).

Have a check of your voltages. In mine (W211), you turn ignition to 2, press reset 3 times and then you have the menu from which you can choose the voltage.

Not sure if the same for the CL.

If it is - my voltage is in the 14s when running which I understand is normal...

 

[Swotty]

Thanks ....... behaved perfectly* today! Will check the voltage as suggested - thanks for the tip how to do it.

* apart from the engine check light coming on, with drop in power. Restarted and performance fine. Check light went out on its own after 3 stops & starts.

Wonderful cars .......... but so temperamental!

Thanks again,

Stuart

 

[Swotty]

Well, the Merc dealer put it in STAR and it diagnosed a faulty blower motor resistor.

The dealer wants £260 alone for the part, plus just over an hour's fitting (c. £120).

The blower motor has always been a little squeaky and I have found this on ebay, motor plus resistor:

Mercedes W220 W215 A/C Heater Blower Motor 2208203142 + REGULATOR RESISTOR | eBay

Not sure if it's OEM (probably not) but does anyone have a view as to whether these people are reliable?

Also, is it easy to fit the blower & resistor myself and does the system need to be reset afterwards? The garage is quoting 20 mins to "re-initialise the servomotors", whatever they are.

Thanks,

Stuart

 

[ahok19]

Thanks John,

Yes, that's the problem. I'm not aware of an alternator issue but will keep an eye open for other signs.

Stuart

Good luck Swoty

 

[BernardB]

Well, the Merc dealer put it in STAR and it diagnosed a faulty blower motor resistor.

The dealer wants £260 alone for the part, plus just over an hour's fitting (c. £120).

The blower motor has always been a little squeaky and I have found this on ebay, motor plus resistor:

Mercedes W220 W215 A/C Heater Blower Motor 2208203142 + REGULATOR RESISTOR | eBay

Not sure if it's OEM (probably not) but does anyone have a view as to whether these people are reliable?

Also, is it easy to fit the blower & resistor myself and does the system need to be reset afterwards? The garage is quoting 20 mins to "re-initialise the servomotors", whatever they are.

Thanks,

Stuart

I'm not convinced there's anything wrong with your car. Just as the heating won't come on fully until the engine's warmed up a bit, the aircon is slow if the interior temp is very high. These I think are designed measures to avoid stressing the systems. Indeed I recall the manual advises driving off with the windows open to lower the temp somewhat before operating the aircon. Strikes me as pretty sensible really.

 

[Swotty]

Thanks, Bernard.

As mentioned, the a/c fan has always been noisy and not too expensive to replace both items together, if the products in the ebay link will do the job.

I know there's a lot of cheap tat out there and was wondering if those units were good enough.

Stuart

 

[John]

I'm not convinced there's anything wrong with your car. Just as the heating won't come on fully until the engine's warmed up a bit, the aircon is slow if the interior temp is very high. These I think are designed measures to avoid stressing the systems. Indeed I recall the manual advises driving off with the windows open to lower the temp somewhat before operating the aircon. Strikes me as pretty sensible really.

I've never read that in the manual but it is something I've done for a long time.

I often see people leave windows and sunroofs open all day.

Never a good idea in case it rains.

I just leave everything shut and when I leave to go home, I open all four windows and let the hot air blow out.

Takes about 5 seconds after starting to drive to do the job.