(1992 240) Any Idea what this AC valve is?

GuyNamedEric · Post by **GuyNamedEric** » 08 Aug 2015, 14:33

Hello,
I cannot identify this part. It is located approximately 1 foot past the orifice tube on the passengers side, just before getting to the radiator. It look like a High Pressure Valve but I cannot find any sort of replacement part for it or anything that looks the same. Hoping somebody can help me to identify this. When I charged the system it was leaking freon from here. Thanks

Post by **jimmy57** » 08 Aug 2015, 17:55

Over pressure relief valve. IF something goes wrong that makes high side pressure go high (420 psi or above) then it opens to dump freon.

93Regina · Post by **93Regina** » 08 Aug 2015, 19:30

GuyNamedEric wrote:1 foot past the orifice tube on the passengers side

Parts show a pressure monitor (3540657), but the pressure relief valve appears to be shown, but not listed.

Click on pic; around 30a and 30b

GuyNamedEric · Post by **GuyNamedEric** » 08 Aug 2015, 20:13

Thanks both of you. Yeah it seems to be confirmed High Pressure Relief. Now finding it has been another issue. This car was retrofitted so maybe this High Press Valve is from a R12 Unit. The search begins.

93Regina · Post by **93Regina** » 08 Aug 2015, 22:21

GuyNamedEric wrote:High Press Valve is from a R12 Unit

I believe 1993 model years were the first with 134a, but there was a Volvo A/C Conversion Kit (240) - Genuine Volvo 9145666

On 1993, I believe the blow-off valve is on backside of compressor, if you can find one in salvage yard.

134a runs higher pressure than R12

93Regina · Post by **93Regina** » 08 Aug 2015, 22:30

Shaft seal kit on compressor was supposed to be changed out if Sanden compressor was installed.

New kits for “Retrofit” has now been introduced. Kits are available as follows.
(See Bulletin for Service Manager Group 87, No 8, Febr. 1994)

Post by **jimmy57** » 09 Aug 2015, 09:09

The pressures of that part for the two refrigerants is minor. R12 used 420-425 psi and r 134 is usually 440 psi.
R134 and r 12 do differ at higher temps but the refrigerant should not get to that temp unless there is a problem.
The BEST thing you can do for 1992 and earlier 240 is to use the 1993 condenser. The condenser was upgraded considerably for the factory use of r134a.

That valve likely leaked on that car because it went overpressure and the ball that seats to keep it closed often gets damaged when it opens since it will cycle rapidly when it vents and scars the valve ball. I have replaced them for leakage on many cars back them that also had faulty fan clutches and the resulting very high side pressure from inadequate airflow over condenser.

93Regina · Post by **93Regina** » 09 Aug 2015, 11:17

jimmy57 wrote:The BEST thing you can do....

I've never examined Volvo's condensers, but are they parallel flow condensers

"Parallel flow condensers are much more efficient than serpentine condensers. The problem is, when a parallel flow unit gets clogged, what we call 'restricted', it can be impossible to clean. The passageways through a condenser can be as small as 6mm in diameter, and debris can really get wedged in there. Flushing has no effect, because the flush simply goes around the restriction."

GuyNamedEric · Post by **GuyNamedEric** » 09 Aug 2015, 11:34

So I have found this part, and it's 40$. Ugh. I'll be going to a junkyard hoping there is one somewhere. Most places list this as discontinued. Or I'll just get the thread size and buy an aftermarket pressure relief valve and stick that in there. Good news is at least this part is easy to get to.