A/C...compressor frozen. R4? what? - PeachParts Mercedes-Benz Forum

blankenship · #1 06-12-2009, 09:11 PM

The compressor on my '85 wagon was locked up when I bought the car a couple years ago, and now that the temperature's climbin' I'm about ready to have it work.

I've never done ANY A/C work before, and am not really sure where to start.

The compressor unit says "Delphi 4354" on it, and I'm assuming it's an "R4" compressor because it looks similar to the photo HERE.
On the Delphi site, that part number seems to "cross" to a "CS0012," which only shows applications for Chevy + GMC, and runs like $300 online.

What the heck is an R4 compressor, compared to R-12 and R134?
Is there any reason to switch systems, and is there a certain compressor, manufacturer, or source you'd recommend?

I'm assuming the first step is to get a leak dye test, and hope and pray that there's a leak in a hose or fitting, and not at the evaporator or something?
What should I expect to pay for the leak test, and can one shop do it just as well as another, or would you stick to a Mercedes specialist?

Ken300D · #2 06-13-2009, 07:53 AM

R4 is just the commonly used model name of the compressor. There's an R6 that was popular for some of the other US cars, for example. It's a little misfortunate that it appears similar to refrigerant type numbers.

For my part I like freon detectors instead of dye. It works well, is quick and easy to do yourself. Check EBay for freon detectors and you should find them under $100 and you'll have a tool you can use a long time on many cars.

If your compressor has locked up, you are looking at a much more extensive repair process than just checking for a leak. You would want to do a compressor, receiver/dryer and probably expansion valve replacement. And a flush. And a vacuum pull. Then refill with freon. Some people suggest replacing the rubber pressure lines too on the theory that hot metal particles from the failing compressor may be embedded inside the rubber tube.

Ken300D

leathermang · #3 06-13-2009, 09:04 AM

R4 probably refers to ' radial 4 cylinder' ..... as compared to the linear types which use things like swashplates to move the pistons.

AC work has the potential to be very dangerous with even slight mistakes. You either need to have someone experienced watch over your shoulder the first time..or you watch them do it...( just like we suggest for first time brake work ) there are too many warnings which you can NOT count on being listed on the forum. Even with that you need to get a book which tells about the theory AND the specific actions you need to take working on your car.

Always wear at least goggles...and I suggest a face shield IN ADDITION to goggles... and potentially gloves also....

blankenship · #4 06-13-2009, 09:57 AM

does the fact that i have an R4 compressor indicate whether i have a R-12 or R134 system?

so, parts-wise, minimum, i'd be in for

$300 compressor
$40 receiver drier
$40 expansion valve
$? freon

PLUS which hoses are you talking about replacing? (There are like (5) different ones...)

What kind of cash am I talking about labor-wise, if I don't get into this myself?

Leak test?
Flush?
Vacuum Pull?
Refill?

Really appreciate your help...it's crazy imagining taking my baby to A MECHANIC and PAYING someone after all this time doing the DIY thing!

kingdoc1 · #5 06-13-2009, 05:43 PM

Air conditioning is a simple heat transfer system, there is nothing mystical about it, and you can fix it yourself with the proper tools and info. Harbor Freight sells a manifold gage set for about $40 and you can make a vacuum pump out of a salvaged refrigerator compressor easily.

I suggest you get a manual on automotive A/C systems such as one sold by Haynes and read and follow directions.

As stated earlier, there are safety precautions to follow.

Here is some info about your compressor and some other vehicles it was also installed on.

A/C Compressor Info
Four Seasons P/N 57228 , Delco P/N 15-20516 (Heavy R4 compressor with clutch)
Part Number 57228

Attributes
Buyers Guide

Description Value
Belt Type Single Groove
Belt Width 1/2"
Coil [48244]
Coil Clock 9
Coil Type Spade
Gaskets / O-Rings: (2)-[24356], (1)-[24357]
Gauge Line A 1.20"
Hub [48236]
Manifold Block w/ O-Rings / Sealing Washer
Mount Std Weight, Metric Threads
Pulley Dia. 5.00"
Reman Clutch Assy [48297]
Reman Compr w/o Clutch [57019]
Switch High Pressure

Description
Buick Regal Sedan / Coupe (87-86)
Buick Skylark (81-80)
Chevy Camaro (87)
Chevy Caprice (90-86)
Chevy Citation (83-80)
Chevy El Camino (87-86)
Chevy Monte Carlo (88-86)
Chevy P Series Van (93-91)
GMC Caballero (87-86)
GMC P Series Van (93-91)
Mercedes 190 Series (84)
Mercedes 240 Series (83-77)
Mercedes 280 Series (81-68)
Mercedes 300 Series (87-77)
Olds Cutlass / Cutlass Supreme (88-85)
Pontiac Grand Prix (87-86)

Part Number 57019 (Heavy R4 compressor w/out clutch)

Attributes
Buyers Guide

Description Value
Gaskets / O-Rings: (2)-[24356], (1)-[24357]
Manifold Block w/ O-Rings / Sealing Washer
Mount Std Weight, Short Shaft, Metric Threads
Switch High Pressure

Description
Buick Estate Wagon (90-86)
Buick Regal Sedan / Coupe (87-86)
Buick Skylark (81-80)
Cadillac Fleetwood / Brougham (89-87)
Chevy Camaro (87-86)
Chevy Caprice (90-86)
Chevy Citation (83-80)
Chevy El Camino (87-86)
Chevy Monte Carlo (88-86)
Chevy P Series Van (93-91)
GMC Caballero (87-86)
GMC P Series Van (93-91)
Mercedes 190 Series (84)
Mercedes 240 Series (83-77)
Mercedes 280 Series (81-68)
Mercedes 300 Series (87-77)
Olds Ciera / Cutlass Ciera (85)
Olds Cutlass / Cutlass Supreme (88-85)
Olds Delta 88 Custom Cruiser / Custom Cruiser (90-85)
Olds Delta 88 Sedan (85)
Pontiac Bonneville (86)
Pontiac Firebird (87)
Pontiac Grand Prix (87-86)
Pontiac Safari (89-87)

Matt L · #6 06-13-2009, 05:54 PM

Watch out with an R4 made for another application, especially one for a GM. Ensure that the front seal oil path is oriented correctly by comparing the front plate to your current compressor.

Ken300D · #7 06-14-2009, 11:00 AM

Is it possible to see this front plate on the compressor with the clutch already mounted? I just want to check my new compressor and I don't know exactly where to look.

Ken300D

Matt L · #8 06-14-2009, 11:06 AM

I don't have any R4's here to look at (our last R4 went bye-bye a couple of years ago).

blankenship · #9 06-20-2009, 02:09 PM

i snagged a compressor with a free-spinning clutch off of a 300D at the salvage yard last week. picked it up for $30. it's a GM OEM "Harrison" brand Model # 1131350, which (though i can't find any info online), i'm betting is identical to the one at this LINK?

Question:
Should I replace my locked compressor with this one, as well as the a/c pressure lines and drier + expansion valve, and THEN have it leak tested and/or filled?
Or should I have my system tested "as is," and then start worrying about repacing components?

#10 06-20-2009, 03:02 PM

If the wrecking yard compressor has the same seal type at the manifold, then I personally would give it a try.

That said, I have a recovery/recycle machine, so if I have to abandon it, I can recycle the R12. If you don't have a means of reclaiming the refrigerant, then it's a crap shoot. If the compressor feels good when turned, smooth and you can feel the compression then the only thing you can't test is the shaft seal.

Was the system you took the compressor off of still holding a charge? If so that would tell you that the shaft seal is probably okay.

For the money you're saving trying this compressor, you can afford to lose R12 although it is unlawful to charge a system with a known leak. In your case you don't know that you have a leak or not.

Good luck

Ken300D · #11 06-20-2009, 05:53 PM

On the junkyard 300D A/C system that you pulled the compressor from - was it still under refrigerant pressure when you removed the compressor? If so, you have a fighting chance that the compressor might still be good. If the system was already opened for some reason and there was no pressure, your chances are much less - possibly due to rust and corrosion issues that come into play when a system is open to the atmosphere for awhile.

On a good junkyard compressor, I would pour in fresh oil to flush it out while turning around the compressor drive shaft. Pour some in, turn it over a few turns, then drain the oil mix out - repeat several times.

Ken300D

johninva · #12 06-20-2009, 06:39 PM

i cant speak to the junkyard compressor compatibility issue. but as far as the ac system being DIY i think it can be for the right DIY guy/gal. I am just learning myself. First you need to really understand what is going on inside the refrigeration system : condenser, evaporator, liquid, gas, high side, low side, expansion device. took many hours of internet research. You need a set of manifold gauges and an electric vacuum pump ( i think the harbor freight ones for 80.00 are passable. ) If the compressor is locked up you need to replace it, i would just go new here, its like the heart of the whole system. open up all open-able connections - flush the lines, condenser and evaporator, to get all the bits of disintegrated seized compressor out of them. replace all o-rings, expansion valve and receiver drier. I was able to pressure test my system with 200psi of nitrogen because I had a buddy with a tank of nitrogen, i dont know how much this would cost if you had to go buy it. I think you could get away with pulling a vacuum and making sure it held the vacuum for a couple of hours, as a leak test. all that said, with the new compressor installed and filled with the correct r-12 oil, fill the system with r-12 refrigerant, by weight. buy the r-12 off ebay. I think the big danger in doing this work is hooking up your r-12 can to the high side by accident and having it explode in you face. dont do that. if you dont know what your doing, dont guess, read more or pay someone. if i have said something absurd here i look forward to being corrected. its all part of learning.

Matt L · #13 06-20-2009, 07:21 PM

200 PSI of nitrogen is fine for the high side, but not for the evaporator. Limit yourself to 150 PSI next time, just in case you are much less lucky.

blankenship · #14 06-20-2009, 09:50 PM

the "salvage" compressor came off a depressurized system, BUT the car had only been at the lot for (2) days. i think it's Oregon law that they empty the systems before putting 'em in the yard. the donor was in damned fine shape...i have pretty high hopes.

isn't there definitely a leak in my system, or the old compessor wouldn't have locked up?

i don't really wanna buy all the tools to DIY the whole thing on this one, b/c my other vehicle doesn't even have a/c, and i don't know if i'm ready to "bite the bullet" on a huge a/c learning curve.

that said, maybe i should just have my system professionally leak-tested and flushed as-is. then maybe i could personally replace whatever components the shop tells me are leaking, and gamble that the "salvage" compressor is good? thoughts on that?

blankenship · #15 06-23-2009, 02:02 PM

hey all-
can you help me with THE ORDER IN WHICH TO DO THINGS?

from what i've been told by a local shop, it seems the compressor and the drier need to be replaced BEFORE the system can be flushed?
and that the system can't be leak tested until i get a good compressor in there?

is that the case, and if so, should i do things in this order:
1. replace the compressor with the salvage one, along with the little green O-rings.
2. replace the receiver drier
3. take the car in to have the system flushed and leak-tested.

also, is my system definitely an R-12 system? based on the attached photo?