R4 compressor - what would you do if you were in my shoes?
 

The old compressor in the 83 300D was giving a high pitch squealing noise when it was on. So I bought a re-manufactured unit from eBay and installed it myself. I don't know who designed the R4! I tried to put 8 oz of ester oil in but it all drained out during installation. What a waste of time and money. Anyway, I changed out the recv/drier, charged 8oz of ester oil which comes in a pressured can then 3x12oz can of R134. Everything work as expected and now I have A/C.

However, the 'new' reman compressor is quite noisy to my liking. I called the seller and he asked me to send it back and he will replace it. What shall I do?

1) I have no R134 recovery machine so I have to vent it to the atmosphere.
2) R&R the compressor again is not something I would like to do.
3) The compressor is noisy and I do not know how long it will last.
4) It is going to cost me $20 shipping, 3 cans of R134, 8oz of ester oil. Probably $70 total. Assuming I keep the recv/drier which is new.

What would be your recommendation? Leave it the way it is?

When you say noisy, how noisy is it? Is it embarrassing noisy or just mildly irritating?

It is difficult to describe noise on paper. I can only compare it with the compressors in the 190D or 300SDL. They sound quiet, i.e. you do not know it is running unless you look at it. With the R4, I know it is running from 10' away. You can tell something is not running quite right.

Answer
 

It sounds like the system is over filled with oil.
Here are the correct volumes.
http://www.peachparts.com/shopforum/general-information/282911-r4-compressor-c-system-oil-charge-per-wis-83-520-a.html


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+1 Roy, 8oz is the total system capacity of oil in that car, so if all you did was change the compressor, and the dryer, you are 6oz overcharged with oil.
you will now need a flush kit in addition to the refrigerant, new dryer and oil to get this car cooling properly.
if it's not been run much, you may not have damaged the compressor with all the extra oil. STOP RUNNING IT NOW!
get a flush kit, and some dry gas to blow it all out with. CO2 is a good cheap choice, but any bottled gas will do EXCEPT OXYGEN!!! DO NOT USE COMPRESSED OXYGEN!@!!!!
get all the lines and coils blown out. you should also replace the expansion valve, but it's not critical, if you remove it and clean it well.

As long as you have to do that much work, you may as well go back to R12. It's easier on the compressor as a bargain.

The R4 should be running PAG150. It requires a higher viscosity oil.

I think the reman unit is the culprit. The issue is whether it is worth my effort to redo all the work. There is no guarantee that a 'new' reman unit will be any quieter. What is the downside if I leave it the way it is? I am leaning towards to do it again when it craps out.

I do not think there is any issue using ester oil instead of pag oil.

I recommend you go with a NEW unit, and go back to R12. That's what I did with my 83 240D (Which has less HP than the 300D) and the A/C works very well. Quiet, cool, even at 95 degrees at 1 mile elevation. Dare I say it - the 240D hardly notices when it is on. You can tell when it kicks in, but it's NOT a huge drag. My R4 reman unit lasted less than a month before it died.

* Get a new R4 compressor
* Figure out the correct sealing washers for it
* Vacuum out all the R134a, it's not as good (IMHO) as R12, purge the system thoroughly.
* Change the fittings back to R12
* May have to change the drier and receiver, etc. (I'm no expert in these things)
* Reassemble, charge with R12.
* Enjoy cool and quiet A/C

You could always go the way of ROLLGUY or the Klima conversion kit and convert over to a Sanden type compressor. No more R4 headaches.

Like P-E, I have a 240D 1983 also, VStech and I did exactly this procedure (except mine has never seen R134a).

More hints from our adventure:
Get a new CompressorWorx R4 from a major chain auto parts store. (Tried to use PP but they could not match the price:(, you will quickly figure it out when you search online for R4 Compressor.) They will do a ship-to-store next day deal.
Got the package deal with the receiver dryer, compressor, and TXV. Go ahead and get the new temp and pressure switches for the dryer too, my old pressure switch did not easily transplant and the temp switch fell apart as I was trying to transplant it. Pick up an o-ring kit if you don't have one already.

Pull the lower passenger dash cover panel, and change out the TXV, it really isn't that difficult if you have the right line wrenches. Change all 4 o-rings. Bonus points if you service the blower while you are in there.

VStech, help me remember the correct oiling procedure, I know we put a portion of the oil in the compressor and the rest in the dryer, correct? How did we keep from losing the oil while installing the compressor?

If you have 2 people it really helps to get the compressor in place, if one holds it from above and the other goes underneath to put the bolts in. Front of car needs to be up on ramps for best results.

Once you get the compressor up in place then carefully remove the dust caps and hook up the manifold. Make sure you use the correct spacer rings that come in the box for the manifold connections.

Once you have it back together, vacuum, then pressure test with dry gas. If it holds the pressure, then vacuum again, and recharge with genuine R12. Only R12. No substitutes.

I can honestly say, on R12, it cools better than either of my newer Hondas with R134a. And we have probably one of the worst environments for AC here in the Carolinas, high 90s ambient and 90% humidity not uncommon in the summer.

And like P-E, I can barely tell when the compressor hits. I can hear it engage, and there is a momentary dip in idle, but then it is silent after that. And I have more cold air than I can stand. Most of the time the temperature dial is halfway between OFF and MAX, and the blower on speed 1 or 2. Even on scorching hot days.

OK :rolleyes:

Have fun swapping those R4s.

This.

I gave up on the R4, even a new Compressor Works one as I could not sort those stepped ports. I have never seen an R4 that was not noisy to some extent.

My Klima kit has been installed for about month now and was a breeze to install. Other kit seems to be popular too.

Just think of all the TIME you have wasted thus far with that R4 and still do not have a working solution...not to mention some cash. Refrigerant, oil, to the autostore and back, etc

What about those stepped ports? I am ready to install my compressor.

I had an aftermarket manifold hose which I think had something to do with it as the flange was not fully square. I looked and looked, could not find a good used one and sure as hell was not going to buy an OE one.

That is why I threw in the towel with the R4.