No Aircon - Advice Please

[VenomX]

Have a C240 from 2002.
Previous owner never used the air conditioning system ( they bought the car in roughly 2003 ) . The AC light stays red even if I press it ( meaning the AC is off )
Checked the fuse, that's fine.

My neighbour did connect some dials to the car and there was definitely some refrigerant, I don't remember exactly what levels.

Would it be best to get a professional to come out and leak test, then if no leak, change the refrigerant ?

Thanks

 

[Petrol Pete]

On a car this age where the previous owner was dopey enough to never engage the A/C you have a few choices , If you have determined that there is some refrigerant in the system you could buy a DIY solution to top it up from Halfrauds/internet top it up and hope for the best.

This used to be a cheap option but the price of the canister of refrigerant has skyrocketed lately and be warned , Buying cheap cannisters of R134a off the internet might find you filling your system with some other gas , fakes are out there.

If it is completely empty DIY filling is not really an option as it might just all leak out and waste money, which is illegal by the way.

The other (and probably best) option is take it to a proper garage and get them to do a full vacuum/dry/fill and leak test.

Replace the cabin filter yourself before going any further , easy and cheap DIY .
Not sure if your car has an Clutchless Variable Displacement compressor but many MB's of this vintage do , you can see why having the correct Refrigerant and the right amount of PAG lubricant in the system is critical. New compressors are expensive.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[E55BOF]

If there's still refrigerant in the system, the problem is likely just that over time, the refrigerant has slowly leaked out (this happens to all systems), to the point where there is now insufficient left to be effective.

Personally, I'd find a local tyre place like Kwikfit or National tyres (there are no doubt others) that will attempt to refill it using an automated machine, quite cheaply, and if that is not successful, find a local aircon specialist to investigate further. It used to be the case that Kwikfit, at least, did not charge if they were not successful, but I don't know if that still applies.

 

[Petrol Pete]

As above , go for the cheapest option first

 

[DSM10000]

Why would someone choose to never use the A/C?

 

[E55BOF]

To save a tiny bit fuel? There are people that daft out there...

 

[DSM10000]

To save a tiny bit fuel? There are people that daft out there...

Indeed. Plus having no idea it has a major role in removing moisture from the air and so prevents misting of the windows.

 

[E55BOF]

The OP has managed without out it since last October. I can recall when air conditioning was rare in cars in the UK, and we all managed without if we had to. Today, I wouldn't buy a car that didn't have it...

 

[DSM10000]

The OP has managed without out it since last October...

Do they live somewhere cold and hadn't noticed?

 

[VenomX]

To save a tiny bit fuel? There are people that daft out there...

Elderly person who grew up in a much hotter country, so our summers didn't feel that hot. Not sure if cost was an issue.

Looking at the prices, the cost of the cannister and the equipment used to do the job properly are quite dear, and seem to cost more than paying someone with the kit
Think I will get an independent professional to have a look and let them do it properly.

 

[E55BOF]

It's your money, but I'd start with Kwikfit or the like; a pro will likely cost a good deal more, and if cheap and cheerful works, you won't need anything else. Get some quotes and see what you think.

 

[VenomX]

It's your money, but I'd start with Kwikfit or the like; a pro will likely cost a good deal more, and if cheap and cheerful works, you won't need anything else. Get some quotes and see what you think.

Good idea, thanks.
KwikFit look fairly cheap at £72 for the 134a which my car uses

 

[E55BOF]

For what it's worth, I do my own. My iCarsoft scanner gives me the data on what the aircon is doing, and I know Mercedes aircon operates at about 14 bar running pressure, and I have a Halfords R134a top-up cylinder. When the aircon stops cooling, I top it up to about 14 bar. I've just done the E convertible; 8 bar is now 14 bar, and it's blowing icy cold again. I did the same on the CLS 63, one of the SLKs, and one of the E-class estates; worked every time.

The CLK had no pressure in the system when I got it last year, so to attempt a top-up would have been pointless. I went straight to a pro, who replaced the condenser (it's almost always the condenser, out in front of the radiator in the salt spray in winter) and refilled the system. That ran at 14 bar too.

A quick and dirty way to tell if there is pressure in the system, if you're unsure and don't have a scanner, is to remove the low pressure port cap (the smaller of the two black screw-on caps on the pipework under the bonnet), and very briefly depress the Schrader-type valve (looks just like a tyre valve) under it with a small, clean screwdriver. You will only lose an insignificant amount of refrigerant if there is pressure, and if not, there will be no hiss and nothing will happen. Keep your face off to one side, though, just in case...

If you're anywhere near Maidenhead, I can recommend a first-class man. He did the CLK, and before that the Jaguar XK, the W210 E55 and another of my many S211 E-classes. His full-time job is installing refrigeration units in vans, and there's nothing he doesn't know about vehicle aircon.

 

[Petrol Pete]

Why would someone choose to never use the A/C?

They walk amongst us.

 

[VenomX]

A quick and dirty way to tell if there is pressure in the system, if you're unsure and don't have a scanner, is to remove the low pressure port cap (the smaller of the two black screw-on caps on the pipework under the bonnet), and very briefly depress the Schrader-type valve (looks just like a tyre valve) under it with a small, clean screwdriver. You will only lose an insignificant amount of refrigerant if there is pressure, and if not, there will be no hiss and nothing will happen. Keep your face off to one side, though, just in case...

Yeah me neighbour had a look when I got the car last year and his kit showed a fair amount in there.
I will get someone out to look, a local guy costs the same as KwikFit and can come out to me.

 

[ALFAitalia]

Kwikfit wont charge you anything at all if if fails the pressure or vacuum test....so you have nothing to loose....That's how I realised I had a leak in my system.....which as it happens was an easy DIY repair. I bet calling a local AC guy out will cost you either way.

 

[mbec212]

Hi, I’ve got a 2015 e220 bluetec - having a nightmare troubleshooting the AC.

When I start the car and press AC, the light stays on for a short time then goes off. No cold air at all. Thereafter if I press it again it blinks 3 times then goes off.

Error code attached.

So far I’ve tried
1) regas
2) changed entire sam module
3) reset via OBD console - compressor voltage still shows zero, but mechanic said compressor works when manually switched on

Already spent hundreds on diagnostics but it has led nowhere.

Greatly appreciate if anyone can help.

Ideas I was thinking - maybe wiring? pressure sensor? valve stuck as it hasn’t been used?

thanks!