Thanks ahead.

I'm trying to get the old AC back to work again by convert it to R134a or just Duracool 12a.

The old compressor locked up so I got new compressor, dryer and expansion valve.

Here are some problems.

1. What is this big silver thing on the ac line in front of the condenser? Couldn't find information about it. I will flush the system and replace O rings, can I flush it or reuse it? What is the purpose of it? It is on the line that's from the compressor to the condenser.
2. I found what seems to be a charging port on the line that goes from the dryer into the car. Based on my understanding, this would be a high pressure line and I'm not suppose to charge through that port. Then what was that port for? Is the old R12 system been charged on the high pressure side? Or I charge it without the compressor running?



The unknown silver thing

The port .

Again, many thanks.

 

The charging port on the high side can be used for charging - with a refrigerant machine and the engine off. My 134 machine by default charges on the high side (with engine off). The machine heats and pumps the programmed amount of refrigerant in. My old r12 machine could charge from the high side also.

DIY without a machine - you need the compressor to suck the refrigerant in, so you must charge on the low side - but there are many 240's (including all the pre 1991 cars that were converted using the factory kits or otherwise) - that have no way to charge on the low side.

That can in the high side line is a muffler. On some cars if possible (usually during a hose replacement) we would eliminate them.

Don't get your hopes up about the amount of cold air you are going to get after conversion. Volvo changed the design of the evaporator and the condensor to be more efficient, and the hose material to be double layered to not leak as bad since 134 has smaller molecules. The Volvo kit (when it was available) included your 3 parts plus a high side hose, an evaporator, refrigerant oil (to drain and fill the compressor) and a 134 charging port to attach to the receiver drier. (to charge on the high side with) Even with the factory kit the coldest they would normally blow would be in the low 50's, warming up considerably when idling. An aftermarket electric fan helped some at idle - but 1991-1993 240's would blow in the low to mid 40's and can cool the car. Mid 50's does not cool the car if it has been sitting in the sun.

Before you start replacing parts - disconnect everything you will need too - AC fittings corrode on the inside and can make removal without stripping/destroying impossible.

If you successfully complete this task - you may end up replacing the heater valve or installing a manual shutoff on a heater hose. The valves will leak hot water into the heater core and since there is no blend door to block off the core - that hot water will warm your expensive new cold air! (before it hits your face!)

 

Thanks for the info!

So if I understand it correctly, it wont hurt anything if I just flush and reuse the muffler right? I'm gonna have a shop pressure test the line, if its not leaking I don't really want to buy a new line for it.

I heard that 12a will have a better result than R134a and puts less stress on the system. The compressor I got do have two ports on each side, one with letter "D" one with "S", I assume the S means suction? maybe I can use that one?

Never thought about the heater core leaking issue, I feel mine blows fairly outside temperature out, but it might just be the inside of the car was too hot to tell.

Not hoping freezing cold air out it, but at least something cooler than the out side, it is a sedan tho, that might give better results

I will have a shop to do the big work properly, but they seems to have some hard time get good information about the old AC system, that's why I'm trying to dig out as much as info as possible here

 

AC machines do not pressure test - they test after pulling a vacuum to check for vacuum leaks - An old 240 system is going to leak under pressure - after being charged - that's just the way it is due to the multiple rubber ac hoses used. Later cars use aluminum pipes, and two short flexible hoses to allow the engine to move - 240's have multiple long rubber hoses, a couple of them close to the exhaust manifold!

For your heater valve - after you have driven the car for a while, reach under the forward side left console panel and touch the heater valve (in the gas pedal area) - if your finger tips feel hot - there is hot water flowing and that hot water will be warming up your just expensively purchased cold air!

 

K, thanks for the advice.

The shop told me they have pressure Nitrogen to test it, maybe I better tell them easy on the pressure not to blow up things.

I tried the heater core today, not hot but slightly warm, nothing warmer than the rest of the car, I guess that's a pass then.

 

The high side can get up to over 300 psi at times (very hot, idling) - I've had many "resurrected" ac systems blow a hose just as you were finished charging it up. Was expensive for a while as r 12 was going up in price!

The low side hose where it drapes and bakes over the exhaust manifold tends to explode.

 

Wow, never thought it will actually blow up, I guess I will take a try of the Duracool 12a stuff then and tell the shop to easy on the pressure.

Thanks a lot for the advices.