AC charge and related leak

[Hokie]

Prior to buying my D the PO converted to R134 and charged the system. The AC worked well for about 4-5 months. Afterwards, nothing. Apparently a leak. I'm letting a local shop charge it back up this weekend. Any advice on common leak areas? I'm told it could be o-rings on the evaporator... How hard is it to work on?

[Henrik]

Prior to buying my D the PO converted to R134 and charged the system. The AC worked well for about 4-5 months. Afterwards, nothing. Apparently a leak. I'm letting a local shop charge it back up this weekend. Any advice on common leak areas? I'm told it could be o-rings on the evaporator... How hard is it to work on?

Do you know if the PO replaced any components when he converted? If so, that would be a good place to sniff for leaks.

Another good tell-tale is the presence of dirt: Escaping refrigerant contains a small amont of oil so wherever there is a leak, there is dirt.

Generally, any joint is suspect. However, the compressor has moving parts and sits on a vibrating, hot engine in etc. so it is often your culprit. If you have a sniffer, check the lip seal (behind the clutch), the oil plug, the valve plate (b/w compressor's cyl. block and head) and the connections in the back.

[mluder]

You can also buy a kit at the auto parts store with a UV flashlight and glasses for around 10-15 bucks. The system has a dye in it that glows under UV.

Cheers
Steve

[Bitsyncmaster]

Most common are the service valves. Put a little soapy water on them to see if they leak. My AC leaked running R134 at the hose from evaporator to accumulator.

[David T]

Most common are the service valves. Put a little soapy water on them to see if they leak. My AC leaked running R134 at the hose from evaporator to accumulator.

The service ports are a common source of leaks. Next are the gaskets on the back of the compressor and all of the seals on the high side. If you still have the original hoses they become very leaky too. Bottom line, every joint and hose can be a leak.

[Ryan S.]

The service ports are a common source of leaks. Next are the gaskets on the back of the compressor and all of the seals on the high side. If you still have the original hoses they become very leaky too. Bottom line, every joint and hose can be a leak.

David
so how do you fix service port or service valve leak?
Thanks

[Bitsyncmaster]

You can just try to tighten the valves in the service ports. You need the long tool for AC work to tighten them.

[David T]

David
so how do you fix service port or service valve leak?
Thanks

Good Practice includes replacing the valve cores during any service on the system. Also throw away the plastic covers and use metal ones. Not only will metal covers (caps) prevent dust and dirt from getting into the valves, it will seal the port and prevent leaks. The plastic ones cannot do that.

[Bitsyncmaster]

Good Practice includes replacing the valve cores during any service on the system. Also throw away the plastic covers and use metal ones. Not only will metal covers (caps) prevent dust and dirt from getting into the valves, it will seal the port and prevent leaks. The plastic ones cannot do that.

He is running R134. No metal caps for that.

[David T]

He is running R134. No metal caps for that.

That applies only if the fittings have been changed to -134. I see all the time systems converted and they still use the -12 service ports. There are adapter fittings you can buy and screw on over the shrader valves but they are expensive and not often used. If he bought new hoses with the -134 fittings that is a different story. Those valves seem to seal well and only need the plastic covers to prevent dirt from getting in. When converting to -134, to do it properly, you are supposed to change all of the seals, the oil, the service ports, and a new label indicating the conversion and the correct fill over the -12 label.

[sweetp01569]

When I bought mine in 2005, it was also converted to R134, and I had it leak tested and charged. For about 5 years after that, I have had seals and O-rings replaced, and leaks tests showing it was tight. For each of those years, I lost the charge over the winter and needed it recharged. I read somewhere that the molecular make-up of the R134 can actually leech throught the original hose material, which I beleive was my problem. I replaced the two long runs of hose that go under the car (using the spliced types available from vendors that allow repalcement without separating body from frame), had it recharged and for the last 4 years, I have not lost the charge and it runs cold in the spring when I start using the car again.

In your case, if no leaks but you lose charge each season, try replacing the long runs of hose with new ones compatible with the R134 gas.


Good Luck,

Paul

[David T]

When I bought mine in 2005, it was also converted to R134, and I had it leak tested and charged. For about 5 years after that, I have had seals and O-rings replaced, and leaks tests showing it was tight. For each of those years, I lost the charge over the winter and needed it recharged. I read somewhere that the molecular make-up of the R134 can actually leech throught the original hose material, which I beleive was my problem. I replaced the two long runs of hose that go under the car (using the spliced types available from vendors that allow repalcement without separating body from frame), had it recharged and for the last 4 years, I have not lost the charge and it runs cold in the spring when I start using the car again.

In your case, if no leaks but you lose charge each season, try replacing the long runs of hose with new ones compatible with the R134 gas.


Good Luck,

Paul

You really should also replace the short hose from the condenser coil to the accumulator too. The newer hoses use what they call a "barrier" type hose which is just a liner inside. One of the problems with a rear-engined car is the use of very long hoses for the A/C. Every hose leaks, even new hoses. In fact there is a spec and it rates the leakage by the foot. It stands to reason, the more hose the higher the leakage rate. The other thing is age. As hoses age they deteriorate and the leakage rate increases. The original hoses were never made to last 20 years and now they are over 30! Using -134 makes things even worse! Not only is it composed of smaller molecules, it is blended and the small stuff gets out first leaving the blend off-balance. On top of that -134 runs at much higher pressures and hotter temperatures. Makes the old hoses time bombs with a short fuse! Don't forget to upgrade your cooling system too. -134 makes that work harder too and that old plastic radiator is also on "borrowed time".

[Hokie]

$$$ !!! Great. :(

[Hokie]

So I picked up one if those DIY kits at Autozone and ended up putting 20oz of freon into the system. First thing I noticed as the freon started to flow was that the compressor came on and stayed on - didn't cut off or "cycle." Is this normal? It's blowing cold today, we'll see tomorrow, but isn't the system supposed to cycle on and off as you drive, rather than stay on? If it continues to stay on and not cycle off and on, what might this mean?

[David T]

So I picked up one if those DIY kits at Autozone and ended up putting 20oz of freon into the system. First thing I noticed as the freon started to flow was that the compressor came on and stayed on - didn't cut off or "cycle." Is this normal? It's blowing cold today, we'll see tomorrow, but isn't the system supposed to cycle on and off as you drive, rather than stay on? If it continues to stay on and not cycle off and on, what might this mean?

If it doesn't cycle you either have too much refrigerant or the low pressure switch needs to be adjusted. This is assuming the blower is on speed 4 and the cooling fans are both working and the coils are clean.

[DMCMW Dave]

So I picked up one if those DIY kits at Autozone ............

What does that kit have you do about making the oil compatible for R134?

It will be interesting to see how long it makes cold. In my experience not flushing the system and changing the oil will cause the orifice tube to plug when the old oil turns to black mud. When that happens you won't get cold air.

It will make the high side go very high (it may switch off due to this, but you'd think it was the LP switch) or if you have one of the systems with out the high pressure valve and switch it may just blow a hose open, depending on how much charge you put in.

What are your gauges saying, high and low, as you rev the engine to 2000 rpm or so?