AC compressor cycles; '93 850; only seeing one port

volvodude · Post by **volvodude** » 01 Apr 2007, 11:41

First time Volvo owner here. I recently bought a '93 850, and was told that the AC worked fine. It was a cold and rainy day, and I believed him. Anyway, it doesn't really work; the compressor cycles rapidly (5 seconds or so). I bought the R134a refrig with gauge. Guage is perfectly in the blue (perfectly charged). There is only one port, near the firewall, has a cap that reads "6mn", and has a R134A tag attached. There absolutely is no other port; I have spent hours looking for it. Also, the line below the 6mn port is cold and wet (when engine is running and ac is on). I do not believe a charge is needed, but do now know why the compressor would cycle, and why there is only one port.

CarVolvo · Post by **CarVolvo** » 01 Apr 2007, 11:45

other port is by your passenger headlight right behind it in the engine bay.

on a 93 you also have on board diagnosis in socket B1 (that too is right beside the winshield fluid filler neck). You can analyze your system there and see what codes it kicks out so see whats up with the system.

Happy Repairs!

greasefingerss · Post by **greasefingerss** » 01 Apr 2007, 17:35

So that

Klausc · Post by **Klausc** » 03 Apr 2007, 11:00

volvodude wrote: I do not believe a charge is needed, but do now know why the compressor would cycle, and why there is only one port.

There is no high pressure port on 850/70s. And the compressor will cycle a lot if you just start the car and let it idle. The 6nm cap is the dust cover for the low pressure port, where you add r134a and take pressure readings.
The AC system on Volvos leaves a lot to be desired, like many European cars, they just do not understand that it can get over 100F in the shade!

Klaus

Black850 · Post by **Black850** » 05 Apr 2007, 11:15

Also, not being an ass here, but use the search as well. There's a ton of previous info on ac stuff that will get you started and will get you information more quickly instead of waiting on a response.

Post by **JRL** » 05 Apr 2007, 12:13

Klausc wrote:
volvodude wrote: I do not believe a charge is needed, but do now know why the compressor would cycle, and why there is only one port.
There is no high pressure port on 850/70s. And the compressor will cycle a lot if you just start the car and let it idle. The 6nm cap is the dust cover for the low pressure port, where you add r134a and take pressure readings.
The AC system on Volvos leaves a lot to be desired, like many European cars, they just do not understand that it can get over 100F in the shade!

Klaus

Oh I totally disagree with you there.
They may fail prematurely with their rusty evaporators but when they're working properly the A/C is as cold as any car I've been in and that's a whole bunch of cars

Klausc · Post by **Klausc** » 05 Apr 2007, 14:17

JRL wrote: Oh I totally disagree with you there.
They may fail prematurely with their rusty evaporators but when they're working properly the A/C is as cold as any car I've been in and that's a whole bunch of cars

When it's nice up here in July, I normally roll down the windows just after I start the car to help it cool down. When the cabin temp is less than 90, the ECC does not go into recirc mode automatically and the compressor cycles every 7 seconds or so. Not until I get the car moving will the compressor stay engaged and the dash air get cold.
As for some American cars, the temps at the vent will be in the low 40's and a cloud will form there when it is humid!

Klaus

volvodude · Post by **volvodude** » 07 Apr 2007, 21:58

Thanks all for the replies! Still cannot find a port behind the headlight, nor anywhere in that vicinity. I saw a pic on either this site or another, showing a capped port, between the power steering pump and the diagnostics ports, but none on mine. I'm thinking that perhaps this car has had some work done in the past, and the system was altered. At any rate, I was also hoping to have affirmed that the problem wouldn't be in the evap, since it shows a strong charge. If a problem existed in the evaporator, wouldn't it be losing charge? Thanks again all... it's still a great car, despite the AC and a few other annoyances. I will probably keep it for a very long time.

Post by **akitawagon** » 08 Apr 2007, 01:01

On my '93 850, there is only one port and it is the one on the right side by the firewall (like the one you found). For the newer 850s, the port was moved to behind the passenger side headlight area.

greasefingerss · Post by **greasefingerss** » 08 Apr 2007, 06:38

I believe you only need to be concerned with the one port that you already found labeled 6mn with the R134A tag attached.

My 1994 850 has this port directly below the Diagnostic Connectors (near the passenger headlight) But if yours is by the firewall then that is it.