A/C parts - PeachParts Mercedes-Benz Forum

bbboomer · #1 07-09-2009, 12:35 AM

Anybody have any experience with Four Seasons A/C parts?
The wife says the a/c isn't getting as cold as it used to.
I haven't checked for leaks yet but I imagine it must be leaking somewhere. It is still R12 and I have a lead on some refrigerant but I want to make sure any leaks are fixed first.
I am hoping maybe just a drier, seals and o-rings.
Anything else I need to check?

Gene Horr · #2 07-09-2009, 12:35 PM

I just did a complete retrofit back to R-12. Any decent shop should have a leak detector which should narrow down the source fairly quickly. It is normal for a small amount to leak each year. Topping off every few years is normal maintenance.

rrgrassi · #3 07-09-2009, 12:37 PM

Four Seasons is aptly named. It usually only lasts the four seasons, or until the warranty expires. Which ever comes first.

#4 07-09-2009, 08:18 PM

I expect that most of their products are of average quality EXCEPT for their rebuilt compressors. In the industry they are referred to as "four siezin's."

leathermang · #5 07-09-2009, 11:37 PM

Quote:

Originally Posted by Gene Horr

It is normal for a small amount to leak each year. Topping off every few years is normal maintenance.

Gene is referring to the designed leak at the front of the compressor shaft which keeps that front seal lubed...

THIS is why you need to start your AC about once a Month EVEN in the WINTER... to keep that seal lubed...
Some cars use the AC when the defroster is on to drop the moisture out of the air... so that takes care of that for them...but if your system does not then you need to do it manually...

bbboomer · #6 07-10-2009, 12:09 AM

Okay,
My wife says she isn't driving the Merc till the A/C is cold again.
I did a cursory inspection and don't see any obvious leaks.
Should I try some colored leak detector or is there another/better way to check for leaks?
The A/C has worked well in the past and I realize that means nothing, but does anyone have any suggestions for where to start?
The sight glass shows a frothy solution instead of a clear one.
I haven't done any a/C work in years but I think I remember that indicating low freon.
I will buy a set of gauges and re-charge a necessary but a little advice/helpful hints will surely be appreciated.
Thanks,

#7 07-10-2009, 06:11 AM

It is virtually impossible to do a meaningful a/c diagnosis without low and high side pressure readings and the ambient temperature to go with them. Assuming that this shows a problem, and at this stage of your statements it's quite certain that it will, you are correct about looking for a leak next.

For a number of years I relied on UV dye and a black light. I now have an electronic leak detector (sniffer) and I don't know how I got along without it. You really need both to do a thorough leak check. OCASSIONALLY in the case of a really stubborn to find leak, pressurizing with dry nitrogen and an ounce of R22 will uncover a leak that has been undetectable with dye and a leak detector.

TchTchr · #8 07-10-2009, 09:39 AM

I'd take it to a shop with the proper equipment.

bbboomer · #9 07-10-2009, 05:21 PM

Okay, further investigation has uncovered this.
The suction side hose has what looks like a R134 fitting on it up near the firewall. The other side of the hose going out to the condensor has the smaller R12 style fitting.
Question... does this hose normally have the large quick coupler style fitting even with R12? Is there any way to tell if the system was converted to R134?
There are no stickers indicationg a conversion and I was told this car had the original R12 in it. Now I have doubts about that.
What are my options?
Thanks,

#10 07-10-2009, 06:26 PM

In spite of the fact that any converted system is required by Federal law to be properly labeled and BOTH fittings be correct for the refrigerant contained therein, very few are. The only way to know what's in it, is to go to a shop that has a refrigerant identifier. Most any shop that has a recycle machine will also have this instrument.

The fact that only the low side has the fitting is a strong indication of a conversion hatchet job. Proceed with caution.

bbboomer · #11 07-10-2009, 08:33 PM

Okay,
It looks like this car has been cheapy retrofit for R134. Another case of MC abuse or in this case A/C abuse.
The question now is do I fix the A/C to perform or restore it to R12.
In this case I am going to fix it to the best of my capability.
I don't really have any choice as money is an issue.
My plan is check and fix any leaks, replace the receiver/drier and possibly the expansion valve, pull the vacumn and recharge.
I know purists will say restore to R12 and that is what I would prefer to do but I need to get this fixed and back in operation.
It is my wife's daily driver.

#12 07-10-2009, 10:19 PM

Given that you are planning on doing all that, it would only be a little more work and expense to do it right and take all the lines loose, flush thoroughly, then put in the correct amount of mineral oil or synthetic substitute, then evacuate and charge with R12. You will have to find and correct the leak either way.

Since you're in Oklahoma, you can use R12 with no trouble and the cost of it is coming down.

I would strongly recommend that you find and fix the leak and do the retrofit to R12. You will then have cold air and a good chance for long term a/c durability.

DocSarvis · #13 07-10-2009, 10:41 PM

Quote:

Originally Posted by LarryBible

It is virtually impossible to do a meaningful a/c diagnosis without low and high side pressure readings and the ambient temperature to go with them. Assuming that this shows a problem, and at this stage of your statements it's quite certain that it will, you are correct about looking for a leak next.

For a number of years I relied on UV dye and a black light. I now have an electronic leak detector (sniffer) and I don't know how I got along without it. You really need both to do a thorough leak check. OCASSIONALLY in the case of a really stubborn to find leak, pressurizing with dry nitrogen and an ounce of R22 will uncover a leak that has been undetectable with dye and a leak detector.

Hey Larry I have a couple of questions. I am like the majority back yard mechanic. I know enough to usually get by but really havent done much with AC systems except read all I can lately and collect gauges fittings and a vacuum pump. Anyhow my questions are on pressurizing the system to check for leaks. I understand compressed air is wet and not so good but how about oxygen or inert welding gas argon co2 mixed mig gas????? I read oxygen is bad but it didn't say why??? Also what does the r22 do for finding the leak? Thanks.

bbboomer · #14 07-10-2009, 10:44 PM

I would really prefer to restore it to R12 but I have never done one before. I am a little familiar with A/C but certainly a novice.
What would I need to flush the system with?
How do I go about doing it?
Will I need to remove the compressor and flush it as well?
Thanks for all your responses and help.

leathermang · #15 07-10-2009, 11:26 PM

Darrell, there are just huge numbers of threads where we have laid out the proper way to do everything you have asked about...

Doc, I assume that oxygen pressurized into the system would oxidize the oil... which is usually a bad thing.. I am guessing on that... .but Nitrogen IS recommended..and the R22 I mention so often is the EPA allowed ( FOUR ounces ) charge for finding a leak and being able to LEGALLY VENT it.... to then put in the refrigerant you have chosen to use.