G.P.

Speedtoys

and I can see movement in the sight glass on the receiver dryer.
---
Thats your problem, and also shows you dont have a blockage...should have no air bubbles at all...they moving,,,cant with a blockage.

"I can feel the pipe warm up at the top of the condenser but it stays cold at the outlet on the bottom"
---
Which means it is flowing in hot, cooling, and flowing out...but the system is really low, so maybe not getting that hot.


You need to put gauges on it. Is the expansion valve cool/cold?

FredR

First of all leaving the a/c in these things without operation for months at a time is not good for the car in general and more so for the compressor seal faces. The seal relies on a fine film of compressor oil to work as intended and if they are left static for long periods of time the oil eventually "dries out" from the seal lip [if that is an appropriate expression] and gas starts to escape. Then when the machine starts up there is no lubrication and the seal face can be damaged. The gas may not be escaping in huge amounts [it can] but over time the amount of charge reduces and eventually there is not enough gas in the system to satisfy the low pressure switch and nothing happens when you try to switch the system on. The system is more prone to this in hot dry climates [ask me how I know]. Even if in good working order, I reckon the system is fine if I can avoid a top up for two years [or more].

The obvious candidates for replacement are the pressure hoses [especially if they are still the original items]- a half decent a/c shop can rebuild them for you and the drier. Modern barrier hoses are the order of the day irrespective of what refrigerant is in there.

Speedtoys has covered the pressure side status in his post.

The Forgotten On

Even if your condenser was blocked, it is a simple fin and tube one. You can simply flush it with a good flush fluid or mineral spirits. They don't have small orifices like modern parallel flow condensers.

But it does sound like the level is low in the system. Get out the gauges and do a pressure test as suggested above. Then do a leak test to see if any of the seals have failed.

If your compressor, seals, and all hoses are original, the system probably needs to be serviced at this point.

jpitman2

If you are playing with condenser, put in a parallel unit.
jp 83 Euro S AT 57k

The Forgotten On

Do you know of one that easily fits the later years? Inquiring minds would like to know

dr bob

jpitman2

Bruce Buchanan down here in Sydney has fitted several apparently. Some mounting bracket work required, from his posts on landshark. Big improvement we are told.
jp 83 Euro S AT 57k

FredR

JP,

When you use the word "parallel" are you talking about fitting an auxiliary condenser to give extra cooling surface area or a new unit with a different pass configuration?

I am quite sure the a/c system is limited by condenser capacity as the automatics do not fare as well as the manuals given the latter has a bigger surface area given the manuals [GTS excepted] do not have tranny coolers in the way.. My friends S4 manual would freeze you nuts off even in our hot summer climate. Mine is OK when cruising but in slow traffic - not so good.

Speedtoys

Early cars has a setpentine style condensor.
Mid models they the S4s and up some, had coil style, more efficient.
The last ones, had parallel flow units, even more efficient.

The 'tell' is the style of plumbing you can see in the condensor, its a long flat serpentine pipe, like a flat garden hose, or a round coil, or really tiny passages left to right from manifolds on each end.

FredR

Jeff,

Sounds as though they changed the design of the condenser when they came out with the R134 version in the later 93 GTS models onwards. I know that model has a different drier arrangement and by the sound of it they introduced a single pass header type heat exchanger that will have a connection on each side. I know I was somewhat surprised when I looked at the R134 performance charts it seemed they did better than the R12 models like mine and that surprised me. I know my friends up in Dubai managed to get a local a/c shop to knock up a better condenser- perhaps it was modelled on the later GTS unit.

All I have dealt with was the units on my current early GTS chassis and my late 90S4 - I know they were identical.

PcarMiami

FredR

The performance charts for R12 and R134 are in the WSM but given they appear to be in seemingly different condensers not sure it would help you much. For sure R12 performs better but not really that much different I would say.

We had R12 available over here long after your part of the world converted to R134. However a few years ago the Government here banned R12 and it literally disappeared overnight- the a/c shops simply kitted their adapters to allow them to fill R12 systems with R134 and did a roaring business changing hoses and drier units! The good news was that such work is relatively cheap here. I had my compressor rebuilt with a new clutch, new barrier hoses, new drier, all fitted and gassed for something like US$150.

Main thing is to get the system working as it can do- if it does then Florida should be no problem for the 928 system. What model year so you have?

Speedtoys

Yup..

bureau13

I'm also in South Florida, and it seems the biggest limiting factor in my '86.5 (converted to R-134a) is the interior fan. It just does NOT move enough air. My '82 924 fan is significantly more powerful, which just doesn't seem right. I know Roger sells a fan upgrade, I'm just not sure how much more air it moves, or if my fan's limitations are due to it being an inferior design, or simply old and worn out.