I have a 1991 Volvo 240. The ac system has been converted to R-134. About the a couple weeks ago, the compressor started making a rumbling sound the first few seconds on start up. Once started, the system’s cooling ability was mediocre as compared to really effective cooling in the middle of the afternoon when the heat and humidity were at their worst (even with a non functional recirculation flap). Now, the compressor won’t turn on at all and I plan to replace it.

This compressor was used at the time I installed it, and I am going to replace it with a new Sanden. Along with replacing the drier, should I also replace the condenser? I’ve been told both yes and no and would like to know from any of you with more experience. Thanks so much folks!

 

If the condenser isn't leaking, why replace it? What was their logic there?

 

I really don't know. I asked myself the same question, but I also realized that there may have been something I wasn't aware of. From what I can tell, it's not leaking, but I'll know for sure once I have the system flushed.

 

Well, the condenser can hold onto old fluid and smells and whatnot... fwiw, I bought a used one for my Evo, and it had a little funk. Once I vacuumed it, and ran some cleaner through it, it was fine.

Up to you I guess if you really want to spend the dough up front... if it's bad, you'll know pretty quick if you should get another one.

My .02.

 

Well, in that case, I won't. When it worked recently, I wasn't getting any odors of any sort, so I think just a flush will do me just fine.

Can I do the flush myself or does it require special equipment?

 

There isn't really a "flush" for AC systems.

I don't have my book in front of me, but in general, the procedure is... collect powerfully harmful gas from the system (drain it), remove the old component, install the new component, vacuum the system, recharge the system to service spec.

In order to do this "properly" you need a manifold. There are various videos on youtube for how to do it... Eric the car guy is pretty good, but you might need to click around to get more in depth info...
When I changed my CONDENSER on the Evo (it's the only one I've ever cared enough to do), I also adjusted the clutch on the compressor. I should've vacuumed the system, but I didn't, I just refilled (since the stone I hit evac'd it for me)... bolted it back up, filled it via factory spec/procedure, and bing bang boom... I'm running 12's with the AC on.

 

not pulling a vacuum before inserting your refrigerant will mean the system is full of air, which will make it less efficient. the air won't liquefy at the pressures developed, so will leave large bubbles of air in the system, this stops the compressor from working properly.

 

Yes, a/c systems can be flushed. That's why companies sell a product generally called "AC Flush".

It is introduced through the system with a machine called an "AC flush machine".
When a compressor dies a horrible death, oftentimes metal particles get circulated throughout the system. Most flushes out easily but certain varieties of condensers tend to retain these metal particles. Leaving them behind ensures an untimely demise of your new compressor. Volvo 240 condensers are not of the design that retains a lot of fragments BUT removing the condenser and pouring some flush through it is always a good idea.

 

Pierce, I have no high side port on my '91 240 system and my new compressor doesn't have one on the rear, so my only option to pull a vacuum is from the low side port at the receiver drier. Is that correct or is there something else I should do or be aware of?

I have the system evacuated today and I'm probably gonna start working on pulling and flushing lines Friday.

 

Only the 89 and 90 models had both ports on the back of the compressor. Beginning in 91 they moved them elsewhere or, in your case, deleted 'em apparently. The a/c system can be completely serviced through the low side. The lack of a high side fitting simply makes fine tuning of the final amount of refrigerant less precise. Too, without high and low pressure gauge readings, it is not as easy to diagnose inefficient compressor operation. Still, not the end of the world by any means.