AC not working low side ok ........

[Ertech]

Hi guys , AC intermittent. compressor engages ,I put the gages low pressure I think is ok high side does not go up .AC does not cycle on and off . ambient temperature 85 . I suspect expansion valve or compressor not pumping . what are your thoughts .
thanks
Erick

 

[gsxr]

Can you unlock the video? And are you certain the compressor is running continuously?

 

[Ertech]

Basically shows this the pressures don’t really move and the compressor is running

 

[gsxr]

High pressure is 150psi so the compressor is compressing. I assume vent temps are like 60-70F?

Might just be low on charge.

 

[Ertech]

I just went to my Mechanic friend who has the big machine he did a vacuum then added 2.2 pound and the high-pressure is not moving just like that picture he suspects the expansion Valve

 

[gsxr]

With a full charge... yeah... the TXV would be my next guess. There is nothing else in the system that would cause this, AFAIK.

However - what are the vent temps? If it's blowing 45°F air out the vents, I wouldn't worry about the gauge readings.

 

[Ertech]

Vents are hot. Thanks for the confirmation. Let you guys know

 

[gsxr]

Ohhhhhh. Yeah - based on what you describe, sounds like it could be a a bad TXV. Unfortunately that requires another evacuation & recharge. Replacing the TXV is not fun, access to it is very limited / tight space to work in.

 

[Ertech]

hi guys I changed the TXV ,dryer 2 sensors and recharge now all is good . Thanks for your help

 

[emerydc8]

Where did you find a dryer? Are they still available in Canada?

 

[gsxr]

Aftermarket (China) driers may be available... but usually for 6-cyl cars, and they don't fit well without some modification (detailed a few years ago on the forum). Great question though, Jon! If there's any NOS OEM V8 driers out there that would be great.

 

[emerydc8]

Thanks Dave. I should see how much modification would be required on the 6-cylinder dryer to make it work, now that they are NLA.

 

[gsxr]

Thanks Dave. I should see how much modification would be required on the 6-cylinder dryer to make it work, now that they are NLA.

OEM is NLA for 6-cyl as well, but there is better availability. More info in this thread, with photos of each.

 

[Ertech]

I have a Worldpac account and they had only one in the system it had a green label with the part number. Not sure about the quality it was $20.

 

[rayhennig]

As temperatures here reach 40C, my 300CE-24 aircon no longer works. It was working a few months ago but never super-cool, although adequate.

The system has worked from 2018 to early 2026.

When I hit the "go" button the revs increase slightly just as they always have. But no cool air.

The system was converted to the approved gas in 2018, having not worked for some years.

Does it seem reasonable that the system might need only a simple re-charge?

As an aside, I have in stock a new MB compressor and MB dryer. I also have a new MB evaporator but I can't face replacing that if a leak is detected in that area.

Does it sound as if I might get away only with a re-charge?

Best to all.

RayH

 

[gsxr]

There's a possibility it may just need a recharge, assuming the compressor still engages (indicating the system is not empty). Don't replace items without knowing which component may be causing the leak (and, the OE/OEM dryer is NLA).

 

[rayhennig]

There's a possibility it may just need a recharge

Yes, that's what I'm hoping. Prestige Cars in the south of England installed a gas conversion kit and a new condenser in 2018 so I assume it had the new gas (134a???). As said, I have the OE MB dryer so I may take that with me.

I'll keep you posted.

Thanks.

R

 

[gsxr]

Don't install the NLA dryer unless you need a new compressor. The dryer is required for the compressor warranty, but otherwise is not a "consumable" that needs replacement. If the system hold a deep vacuum for at least 30 minutes it may be tight enough to hold a charge for at least the summer season.

 

[rayhennig]

Don't install the NLA dryer unless you need a new compressor.

I'm really hoping for a simple solution but I do have a new MB compressor if that's the problem.

R