Car is 1992 300D. Just noticed that the entire top of the AC receiver drier is coated with some greenish stuff (the color of coolant) that's easily wiped off. What is it? How did it get there?

(Yes, I have the green coolant in there; yes, I know that is bad; yes, I plan to replace the coolant with Zerex G-05 when the weather warms up.)

Thanks.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

It's been a while, but I know I've had dye in the refrigerant....is that the typical color of dye?

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Yes, the dye is a green color.

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92 300D 2.5L OM602 OBK #59

Probably means leaking O-rings on the receiver dryer or a bad hose and you're leaking refrigerant that is carrying the oil along with it. The oil can be neon green due to the dye. Probably worth a UV-inspection for other leaks before you fully commit to fixing it. Make you sure you know if it's 134a or R-12.

When my daughter had the car in VA about a year and a half ago, it was diagnosed as having a leaking compressor and RD. I'm guessing that's when the dye was put in. I don't doubt that the compressor is leaking, but since SO much of the green stuff is around the RD, I'm wondering if that's the lionshare of the leak.

Last summer I added refrigerant once or twice and made it through the season.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

If by "green thing" you mean "green dab of paint" or "green plug that covers the sight glass" then no. If you mean "oily green coating" and it's near the air conditioning components, then yes, I'd get it checked.

When in doubt, post a pic of what you see. Uploading attachments is easy. You frequently get a free, unrequested diagnosis of other items in the pic.

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