Automotive Air Conditioning Information Forum

It certainly seems like the Blend Door Actuator is receiving a false signal. But before we go to the control module again, let's examine a few other things that you might be overlooking.

Seems simple, but have you checked the cabin air filter? A partially clogged or fully clogged filter sometimes ...

If memory serves, Mahle bought out RTI ten or 15 years ago. I never owned an RTI machine, so I don't know whether parts are still available.

My guess is that Mahle gave up the old RTI product lines, along with parts production, due to lack-of-market. In today's digital-centric world, I doubt that ...

It sounds to me like the refrigerant charge is "off." What does the under-hood decal say about the amount of R-12 that should be in it? Does the evaporator freeze-up the way it is?

The system still might have a leak, and/or could have air and moisture in the system.

A system that holds vacuum is ...

I don't know what area of the country in which you live, but any of the major automotive flea markets, like Carlisle or Hershey—held every Fall in Pennsylvania—can occasionally turn-up used machines. On-line auctions are another source.

However, the phrase *caveat emptor* comes to mind. Often ...

Unfortunately, I don't have access to the specs for your vehicle because I'm in the USA. However, there are some clues that might point us in the right direction.


Yes, the compressor runs all the time, there is no magnetic clutch.
A clutchless compressor that runs all the time must be a variable ...

Kindly post the year, make, model, engine size, and mileage for your vehicle. Is this a US-spec or non-US-spec vehicle?


My question is regarding constantly running ac compressors.
Your topic says, in part: "...re constantly running ac compressors." And your post above states essentially the same ...

grumpy old man wrote: Mon Mar 30, 2026 2:18 pm ...I think it is classic air. Had I known about them I would have gone that route but 20 20 vision is only hindsight.

My thought, too. There are a few of those companies around: Classic Auto Air, Old Air Products, Vintage Air, et al. .

I got it in the available space but with all the ductwork I needed to manufacture with the fan in high it has the air flow of the average unit with the fan speed on 2 of 4. All the twists and turns cause so much restriction that I need a much more powerful fan.
Have you tried larger-diameter ...

The under-hood decal always takes precedence over the manufacturer-published specs. That makes it 1.35 pounds times 16 ounces, resulting in 21.6 ounces net weight of R-134a.

The UV dye, added sparingly, won't hurt anything.

On the decal, does it specify what viscosity of oil your system takes? PAG ...

I also wanted to add there is a rattling noise with compressor running.
A rattling noise when the compressor runs usually indicates that the refrigerant charge is "off"—either undercharged or overcharged—and/or something is wrong internally. Since it's the original compressor with ~156,000 miles ...