MB air conditioner blockage?

dan76n · 04-12-2021, 09:56 AM

Hi All,
My 2009 MB mondeo was starting to have issues with the air conditioner not working so I’ve put it into an auto electrician who said it’s got a blockage and will be one of two things.
A TX valve or the compressor and if it’s the compressor it could need replacing or just need some valve on it replaced.
They suggested the TX valve being the first step so replaced that but it didn’t fix the problem so $400 down an now I’ve got to decide next step.
Do I get them to replace the whole compressor at a price of $1600+ or just the valve on the compressor and hoe the compressor itself is fine. That will cost $700ish.
Prices are estimates as apparently the compressors are really difficult to get to labour could increase.

Any suggestions?

11ford11 · 05-12-2021, 08:09 AM

And if the valve doesn’t fix the problem you’re going to be up for the cost of the valve and a new compressor
Have you checked cost elsewhere

Citroënbender · 05-12-2021, 09:57 AM

A number of the wholly mechanical displacement control valves have a poor reputation for life vs the overall compressor.

That said, I think the cost of gas and ARC compliance in Australia, negates savings trumpeted by people in countries like the US where such strictures don’t apply. I’m assuming the compressor replacement quote includes all items and procedures to validate its statutory warranty.

Franco Cozzo · 05-12-2021, 12:23 PM

Good rule of thumb to live by is don't ever turn your A/C off, keeps refrigerant circulating and moving around all the time, mine is on every time I'm driving the car and I regulate the temperature inside the car by using the heater.

My Focus has 230,000km on it, AC has never been off, no compressor noise at all and its cold AF.

Our WS Fiesta, A/C never gets used, noisy AC compressor when it does get used, car has 90,000km on it.

dan76n · 13-12-2021, 05:17 PM

Next chapter of my Mondeo.
So we decided to get the compressor replaced and now have another issue.
I've been told that the fan is cutting out and telling the computer to shut the compressor down.
Apparently it was all working but then the Fan is switching off which then causes the compressor to shut down.
It's either the wiring has a break or the fan module is faulty.
My issue now is that I actually think this is still the original issue and the TX valve and compressor weren't actually faulty as the aircon would occasionally work then stop which is what the tech told me today.
They are claiming that sometimes you get a bunch or issues at once.
I kept the old compressor just in case and have told them I need to think about my options.
Should I just take it elsewhere now?
It's getting quite costly and still no air-conditioning.

Citroënbender · 13-12-2021, 06:22 PM

I presume you mean the cabin fan?

Many have a thermal trip on the controller module, if current draw is excessive (due to worn brushes, stiff bearings) it will shut down - which does block the compressor clutch engagement signal.

Other stupid designs I’ve seen energise the clutch coil by a solid state relay on the climate control board or body module. Great theory, fails in practice as loads exceed design specs.

You really need to view the live parameters to see what the controls think they are doing or reading. Actuator tests are also handy.

To be fair, most systems can be reasonably diagnosed via experience but the presence of a less common fault or inadequate previous work may complicate.

dan76n · 13-12-2021, 07:27 PM

Sorry no I mean the radiator fan.

Citroënbender · 14-12-2021, 09:56 AM

The problem with the fan - if there is one - will likely be suitable to test out rather than just “plug and pray” with a new controller module. Reference to the factory (workshop) manual for pinpoint tests will be required.

Franco Cozzo · 14-12-2021, 07:23 PM

I'm assuming if the fan isn't working, you'll be having the problems with the AC in traffic/slow speeds? If you have limited air flow through the condenser It'll cause high pressure and trigger the A/C cut off.

Its also worth checking if the fins and in between the radiator and the condenser are clogged up with crap like dirt/leaves, that'll do it too.

cobrin · 14-12-2021, 08:37 PM

My Fan Controller failed on a long drive (on holidays), when it doesn't work, the condensor overheats and trips out the AC system, it's an over temp. fault, a system protection essentially. What makes it worse is because it's the only fan (3speed) it affects the engine cooling system and thus the engine. Out of safety for the engine destroying itself, I had to replace it. It was just my luck that at 100kph on the HWY @ 48DegC it was enough airflow to keep the coolant temps down, whilst the AC wasn't able to be used.

I was in Airlie Beach (A.B) so sourced one from Ford in Brisbane and had it delivered to the guys in A.B, now because the Fan Controller is part of the cowling and fan itself, you have no option but to buy the whole thing, I think it was $800. Sucks but I never had a problem again with the system, so there's at least that.

As for the AC compressor, it's easy as pie to remove, don't let them tell you otherwise. The compressor should be $750 from Ford bought one earlier this year.

This mob doesn't look like they know what they're doing, I'd seek help elsewhere.

dan76n · 15-12-2021, 07:11 PM

I haven’t checked myself but apparently the fan runs fine when the aircon is switched off but when you turn the air con on something is tripping and telling the car to turn the fan off.
The tech was saying it’s a common issue for the wiring harness to get damaged and cause this problem but If it’s not that then it’s the fans control module which requires the whole fan to be replaced.
Just googling and it seems you can buy a fan control module separately to the fan and it’s not too expensive.
Would it be worth me just replacing that at seeing if that fixes the problem?
I’m so frustrated as it looks like I’ve paid to have the TX valve and compressor replaced for nothing. They obviously won’t admit that but the fact that the same fault exists from prior to them doing this work seems that way. I highly doubt I picked up two seperate issues causing the same problem at the same time.

cobrin · 16-12-2021, 04:15 AM

Quote:

Originally Posted by dan76n

Would it be worth me just replacing that at seeing if that fixes the problem?

I wanted to fix the issue for good, so I had no choice but to replace the whole assembly. It was squared away after that, and its that result that makes it worth it in my eyes. its your choice as to what to do. Good luck mate.

11ford11 · 16-12-2021, 10:09 AM

Is the tech who is suggesting the fault is now in the wiring or module the same one as carried out tx valve and compressor replacement

Have you scanned for fault codes
Does compressor clutch disengage when fault is present
When ac shuts down and turns radiator fan off does engine overheat if you keep it running

dan76n · 16-12-2021, 10:34 AM

Quote:

Originally Posted by 11ford11

Is the tech who is suggesting the fault is now in the wiring or module the same one as carried out tx valve and compressor replacement

Yes, they are saying the fault was a blockage but now another fault showing to do with the fan

Quote:

Originally Posted by 11ford11

Have you scanned for fault codes
Does compressor clutch disengage when fault is present
When ac shuts down and turns radiator fan off does engine overheat if you keep it running

I don't have a scanner so no but was thinking of getting supercheap auto to do it for me.
Not sure about the compressor clutch but will look into.
I've read somewhere else that if it's the wiring harness (purple wire?) then the fan won't work at all so I'm going to drive it today then sit in idle with bonet up and see if fan kicks in (with air off).
Also car hasn't overheated at all.

dan76n · 07-01-2022, 02:47 PM

Hi all,
I ended up getting the fan replaced which seems to have rectified the cooling issue finally.
What I have now noticed though is that when the air conditioner is on it makes a slow pulsing hissing sound. It’s quite loud unless I have the radio on and I’ve never noticed this before.
I’m on AL at the moment so will take back to auto electrician when I return but does anyone know what could be causing this?

By slow pulsing hissing I mean it hisses for a couple of seconds then fades out to nothing then fades back to hissing and it’s constantly doing this while the air is on.

thebigd · 09-01-2022, 12:43 PM

Quote:

Originally Posted by dan76n

By slow pulsing hissing I mean it hisses for a couple of seconds then fades out to nothing then fades back to hissing and it’s constantly doing this while the air is on.

Have you checked that the condenser is not blocked internally ?

dan76n · 14-01-2022, 03:03 PM

Quote:

Originally Posted by thebigd

Have you checked that the condenser is not blocked internally ?

How would I do that?
I took it back to the Auto electrician who's done the work and they said it sounds like air is leaking in the dash through a vent seal.
Said it won't cause any issues.
I think I'm going to need to take it to Ford now but might wait for next service if it doesn't die on me.
Sound is definitely coming from inside dash and you can't hear it from engine bay with bonnet up.
It sounds similar to the sound my split system occasionally makes at home but it's constant.

thebigd · 14-01-2022, 07:55 PM

Quote:

Originally Posted by dan76n

How would I do that?

My local Future Auto Service Centre was able to vac check my daughters condenser on her Pulsar recently. They said it was blocked with oil. It was causing the compressor to cut out moments after it turned on, and making similar noises to what you described. A new condenser worked in this case, and the aircon is now working good as new.

11ford11 · 15-01-2022, 11:00 AM

Other than checking no debri has built up around condenser the only way of checking for blockage is with gauges to check pressures

Does it still have noise if you turn system on then turn compressor Only off -wait a little bit for it to settle

dan76n · 16-01-2022, 10:11 PM

Quote:

Originally Posted by 11ford11

Other than checking no debri has built up around condenser the only way of checking for blockage is with gauges to check pressures

I’d assume they would have done this at the auto electricians.

Quote:

Originally Posted by 11ford11

Does it still have noise if you turn system on then turn compressor Only off -wait a little bit for it to settle

Tried this today and no noise with AC off but fan still on.

dan76n · 17-01-2022, 08:06 PM

I noticed this afternoon when I was outside the care while running that the main engine fan also pulses while the aircon is running (as in it sounds like it gets faster then slower). I'm assuming it's in sync with the hissing I hear in the cabin.

azzrock · 23-01-2022, 02:27 PM

Is the suction side of compressor sweating when running

azzrock · 23-01-2022, 02:29 PM

Quote:

Originally Posted by dan76n

I noticed this afternoon when I was outside the care while running that the main engine fan also pulses while the aircon is running (as in it sounds like it gets faster then slower). I'm assuming it's in sync with the hissing I hear in the cabin.

Quote:

Originally Posted by ivorya

Australian distributer of Bluefin

"http://www.gccorp.com.au/automotive/index.php?osCsid=9358e206fd15a02f8e1ba3d46f7c54ac& manufacturers_id=55&osCsid=9358e206fd15a02f8e1ba3d 46f7c54ac"

Hot wire the fan with 12v then see if your AC is pumping out cold air

dan76n · 23-01-2022, 10:34 PM

Quote:

Originally Posted by azzrock

Is the suction side of compressor sweating when running

Sorry what do you mean by sweating?

azzrock · 24-01-2022, 05:00 PM

Cold condensation on the return pipe work right near the compressor.

dan76n · 25-01-2022, 07:39 PM

Quote:

Originally Posted by azzrock

Cold condensation on the return pipe work right near the compressor.

I know the silver pipe near the dash in the engine bay has this but will check near the compressor next drive.

dan76n · 26-01-2022, 04:33 PM

Not sure if this is related at all but I managed to burn my foot when I put it on these pipes that are the the left of the brake pedal.
Does anyone know what these pipes are and are they supposed to be really hot all the time?
I turned the air on off and they still get hot.