Repairs on my ’98 Mercedes e320

I used to have a 1998 Mercedes E320 Station Wagon.

We bought it used a long time back. At that time it had around 98k miles on it. I has been driven cross crountry twice! A very reliable vehicle but age is showing on it now. At this point we have around 157k miles on it.

Recently I have had a slew of items break down:

Here is what needed to be repaired:

  • The driver side headlight’s xenon ballast conked out.

It was extremely expensive from the dealer [$1000] I replaced it with an after market one for $25! [gotta write that story]

  • The AC’s blower motor’s regulator conked out. I replaced it with a used one $250.
  • Now the AC is leaking. I am currently in the process of troubleshooting and repairing the AC

Here are my notes on its AC repair:

I started a thread at I am hoping to get help from the community.

Other helpful threads: 

AC Quits Blowing Cold Air

 Compressor Oil

It takes PAG46.

 Make sure your PAG oil is double end-capped (DEC) PAG [The new PAG oils on the market are DEC anyway but make sure] They are much more stable in the presence of water. 

Quantity of oil [as per the manual WIS] 

130 ml needs to be added if you change the compressor [drain the new compressor and add 120 ml + 10ml if you replace the drier…..drier changing is mandatory anyway]

 Draining oil from the compressor: [credits to Matt L]

You remove the crankcase plug from the compressor and drain oil from there and the ports while turning the shaft.


Pressures are dependent on the ambient temperature. Hence we use a chart for this.

  • Max. high side pressure 220-240 PSI
  • Low side pressure 40 PSI

 Leak detection

A tool is helpful for leak detection. I heard on the ‘net that this tool is good: TEK-Mate Refrigerant Leak Detector

 I ended up using a cheapo black light bulb from Home depot to detect where the leak was coming from. The dye in the oil glows green. I quickly found out that the condensor in the front of the radiator was leaking.

AC flushing:

Here is some detailed info I compiled into a post:


  • Note that running undercharged for a very long time will also kill your compressor due to lack of oil migration.

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