Warm air after new condenser & recharge.

[Conor]

Hello all,

Trying to get a handle on this as to next steps.

I recently changed the condenser in my S212 E350 and then got it recharged. Mechanic said that it held vacuum no problem so no leaks.

He then said that the A/C just isn't working, something wrong. He is a friend, and was doing the recharge as a favour, but didn't have time to look at anything else.

He mentioned the pressure sensor could be an issue.

No codes on my ICarsoft, and my STAR is currently out of action. I'm going to another friend tomorrow and will see if I can read live values etc.. what should I look out for?

Any other ideas? On Saturday I am setting off back to London from Ireland and I was really hoping for a bit of A/C ..

Thanks a lot
Conor

 

[Mr Greedy]

You can look at the live data for pressure sensor. I have a w212. With ignition on at around 20 degrees after overnight, with cold engine and without the engine running, you should have 5 whatever the units are reported in icarsoft. Bar maybe? Might be PSI. Maybe MPa.

What live data reading do you get for aircon pressure?

 

[Mr Greedy]

Just double checked.
After a regas the day before, leaving the car overnight and checking the aircon system pressure, icarsoft reported 5.3 bar at 21 degrees with a cold, not running engine.

 

[M80]

I did a reset with my iCarsoft V2 on the 211 and then it blew cold.
I think I just clear codes, even though I don't remember there being any.

 

[Conor]

Thanks everybody.

I've hooked the car up to a LAUNCH tool and read a lot of data.

It's quite hot here today and the refrigerant pressure is reading over 8 bar.

I have tried every actuation and test etc ans nothing seems to work. It's very bizarre.

 

[mattkh]

Is the compressor clutch working...?

 

[Conor]

Is the compressor clutch working...?

Probably not... how can I check that? I don't know.

 

[alexanderfoti]

Firstly, the pass of the vac test does not = no leaks. Only cars with wide gaping casms of a leak will show on the vac test. Additionally, most cars with leaks will pass a vac test, as it pulls all the connection(s) Tight and stops the O-rings leaking. They then leak under the 20+ BAR of pressure on a hot day.

However, if you have 8 bar on the sensor, you still have some gas in there.

I know your 212 has a penchant for oil leaks Often, oil leaks into the pulley and destroys the rubber in the damper, causing the inner shaft of the AC compressor to stay still whilst the outer pulley spins.

Your compressor should be a swash plate type, with an actuation valve on the side, so no "clutch" per se. It can vary its outpout by varying the plate angle vs the old style compressor.

 

[Uncle Benz]

Or front SAM issue which can lose the signal to the compressor. Common on 171 and 204. Not seen it on a 212 myself, but they are similar

 

[Roxie]

At 8 bar it should be working. Does it get cold if the engine is cold? I have seen these that have a blend air flap stuck in the heating position so the cold air gets heated back up.

 

[Mr Greedy]

It's quite hot here today and the refrigerant pressure is reading over 8 bar.

Is that 8 bar first thing before starting the car?

What temperature was the scanning tool reporting for the system/ambient?

8 bar sees very high for engine off. Does anyone know if pressure is too high it might not work.

If not whilst stone cold and unused:
Taking a reading with the car running is meaningless. The system varies in temperature depending on heat load. The speed of the compressor changes. The reported pressure varies as you look at it.

 

[alexanderfoti]

8 bar is about right depending on ambient temp. Expect it to rise to about 12-15 bar depending on heat load. It will turn off if too high, but has to be above 27ish

 

[M80]

I've just looked at the 639, the engine was run for maybe 2minutes around 2 hours ago. Now with engine off it reads 4 bar.
I think that's reasonable.

 

[Conor]

OK thanks guys.

Engine had been running a bit.. and it was also warmish outside.

I'm kind of stumped.

I played around with diagnostics and actuated all the flaps etc.. to no avail.

I will say though... that when I press the A/C button I hear NOTHING change in the engine bay..i am used to hearing a slight change in revs or at least something clicking or actuating.. such as the clutch.

As per Alex's suggestion.. perhaps oil has disrupted the compressors pulley system in some way.. God knows that the engine bay has seen a fair shot of oil.

In defense of the car...in my ownership I think it was mostly my fault LMAO.

@alexanderfoti .. what you reckon next steps are? Remove the pump and get refurbed or replace?

I'm guessing refrigerant needs to be removed? Can a garage remove the gas and hold it as a credit for me and/or add it back to the system?

Cheers.

 

[pgh13]

I took my W211 to an aircon specialist when cooling was intermittent. He explained that problem was with a valve on the compressor, so, while thinking, DIY; replace the valve; but then, practicality..... I'd have to get the system drained, replace valve (assuming availability) get regassed.

So, got the pros to do it for £475 total which I didn't think was too bad when a compressor alone could be 200+

 

[Conor]

Alright folks.. thanks for all the input.

What would be the next steps in working towards a functioning system again?

As per @alexanderfoti - If it's the rubber failure like you suggest, is that a new compressor?

Anything else worth checking before compressor change? Fuse? Somebody mentioned that perhaps I should put a meter on the connection to compressor...?

An aftermarket compressor on auto-doc doesn't seem too expensive tbh. What brands are good?... I mean, a Mahle unit is €275 EURO. and not a core exchange.

 

[pgh13]

They said they'd fitted a Delphi, as was the original

 

[alexanderfoti]

Alright folks.. thanks for all the input.

What would be the next steps in working towards a functioning system again?

As per @alexanderfoti - If it's the rubber failure like you suggest, is that a new compressor?

Anything else worth checking before compressor change? Fuse? Somebody mentioned that perhaps I should put a meter on the connection to compressor...?

An aftermarket compressor on auto-doc doesn't seem too expensive tbh. What brands are good?... I mean, a Mahle unit is €275 EURO. and not a core exchange.

You can swap the pulley, but sometimes they are stuck hard on the compressor, so might be worth swapping the whole thing for sanity sake.

 

[Botus]

if it worked before - as in was working till you did the job last week - not it worked 2 years ago, I finally put a condenser on it and now its still broken, why wouldn't it be a controls issue locking out the compressor

I thought (pretty dam sure) merc like to trip people up deliberately turning it off in software - when you go in with the right kit and say hello I'm not a mug - behave yourself ! which usually means - clearing the faults with a high end diagnostic device - the system will just turn back on

 

[Conor]

if it worked before - as in was working till you did the job last week - not it worked 2 years ago, I finally put a condenser on it and now its still broken, why wouldn't it be a controls issue locking out the compressor

I thought (pretty dam sure) merc like to trip people up deliberately turning it off in software - when you go in with the right kit and say hello I'm not a mug - behave yourself ! which usually means - clearing the faults with a high end diagnostic device - the system will just turn back on

You see the symptoms are slightly different this time around.

2 years ago, it didn't work because it had no gas.. and when I press A/C it would just flash red and go off. Now, that doesn't happen.

I've been in the ECU with diagnostics, and there are no faults.