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Discussion Starter #1
Hey yall,

I ordered up all the parts to (hopefully) repair the AC on my 2000 ML320. The shop says a leaky expansion valve so I ordered an expansion valve, drier, and o-rings. Bought a vac, gauges, and freon so hopefully I can get this things fixed.

My questions is I know I need to replace PAG oil but how much and what kind?

I can't find the amount needed when replacing the expansion valve and drier or what weight is recommended.

Any other suggestions or advice for fixing my AC is appreciated.

Especially getting to that drier....


Thanks a lot!
 

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'02 ML500 (Kleeman headers, tune, AMG ML55 wheels,3.09 diffs, 3rd row seats);
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Hey yall,

I ordered up all the parts to (hopefully) repair the AC on my 2000 ML320. The shop says a leaky expansion valve so I ordered an expansion valve, drier, and o-rings. Bought a vac, gauges, and freon so hopefully I can get this things fixed.

My questions is I know I need to replace PAG oil but how much and what kind?

I can't find the amount needed when replacing the expansion valve and drier or what weight is recommended.

Any other suggestions or advice for fixing my AC is appreciated.

Especially getting to that drier....


Thanks a lot!
Wouldn't that info be in either the Owner's Manual, or an underhood sticker for the AC system??

Hopefully someone has a precise answer, I would GUESS that 2-3 oz. would be "safe" even if not optimum, but that is just a GUESS.

Regards,
Jerry
 

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02 ML320 06 ML500
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PAG 46 and when replacing the receiver/drier it calls for 10 cm3 which translates to 1/3 oz. of oil.

Here are the instructions to remove the receiver/drier. Remove the headlights and then the upper cross member. A small female torx socket is necessary to remove the very small screw. Don't lose it.
 

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Discussion Starter #4
Thanks!

43sqd, you're the best! Thanks so much!

Any oil for the expansion valve?

I'll report in a week or two with how it goes.
 

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Current 2017 GLE350, 2007 S550, 2002 S430, 1998 ML320 Deceased 74 240D, 92 400E, 97 E420, 13 GLK350
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Tips for the expansion valve replacement:

- There are two metric socket caps used to hold the valve in place. 18-8 Stainless 5mm x 0.8mm x 50mm. You may want to have one or two on hand in case they strip out on reassembly. (www.bolt depot.com)
- The firewall mounts holding the low and high pressure side hose need to be removed to give clearance to the valve.
- Use a standard slot screwdriver of the smallest size (I used jewlers) to get underneath the groove to remove the inner O-Rings. These are inside the firewall and tough to get at and cannot be pried out with fingers due to confines.
- Lube up the new O-Rings with PAG oil before reinstallation.
- Put the new O-Ring on a needle nosed plier tip in order to expand the ring around the hose fittings inside the firewall, then push on with fingertips.

Shop Instructions attached. Courtesty of 43sqd helping me out earlier.

Tips for the drier:

- The grocery store is a great source for: measuring glass for PAG oil, bakers funnel for putting PAG into the drier, and a kitchen weight scale for the correct amount of R134a.
- Do the drier last. Keep the caps installed to keep out humidity.
- A 4mm socket fits perfectly over the torx for removal of the clamp.
- The forward 10mm cap screw on the drier is easy to remove first and install last. Then pull up on the drier (its a flexible high pressure hose) to get at the back fitting.
 

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