What is this leak?
 

My 300D (85) constantly has a slight drip coming from the bottom of the Delco AC compressor. It is light in color, either yellow or light green?? and appears to be a light weight oil of some type. It's not comimg from above the unit and is not power steering fluid. It collects at the bottom of the unit and then drips to my garage floor. AC is working. Is this coming from the compressor itself? If so, what is it and should I be concerned.
Thanks,
Gene

Any dye put into the AC system to check for leaks?

Check the weep hole on the water pump.

yup, it sounds like antifreeze to me
 

what color is the coolant in your overflow tank? does it match? if so that may be the problem... and if it is, better get that fixed before your head gasket goes south!
John

The leak definitely is not antifreeze. (yes I'm running with Zerex G-05). The leak has gotton progressively worse and it is a clear oily substance. Today the AC stopped blowing cold. It appears to be coming from the area where the two hoses are mounted to the back of the compressor with some type of bracket and and a bolt holding them into their connection. I suspect there is are O rings involved. Could this be AC oil? Anyone know if there are O rings in this connection and can they be replaced? If there is a leak in the AC system I suspect this is it. The dye sounds like a good idea. Can this be purchased at an auto parts store?

The system has been converted to R134 and I just recharged it two weeks age to get it blowing cold.

Thanks,
Gene

You compressor is leaking. The oil is the PAG or PAE oil used for the R134. That connection is called the manifold hose. Under the connection are 2 "Orings". Large and used for AC compressors.

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1SV16GHLO1SV17CL83&year=1984&make=MB&model=300-TDT-001&category=R&part=A%2FC+Manifold+Seal+Kit

Need to replace the "orings", Dryer, evacuate the system and recharge.

Dave

But not necessarily in that order.

I'll bite. What's wrong with that order????

Thanks for all the good tips and link to the correct parts. I think it is probably the o rings at the connector. I bought some R134 with ultraviolet dye, the light, yellow glasses etc and I'll do some checks first. I was figuring on having to replace the entire compressor so this is great if indeed it's just the connector. (Advance can get me a rebuilt with the clutch for $108, and the dryer for $65). I also just purchased a full set of AC guages and toy like vacuum pump at Harbor Freight. The guages look good buy I don't have much faith in the pump since it was only $9.99 and runs on an external compressor. Any info out there on were to buy the right type of vacuum pump that won't break the bank?

I've seen lots of discussion about using R134 vs original R12, but nothing really detailed and compelling. I don't see R12 for sale in any of the auto parts stores and from what I've seen online, it's only sold in large quatities to licensed shops for a high price. If anyone could direct me to any links or hard copy books that would provide detailed info on this subject, such as correct pressures etc it would be most appreciated. I've seen threads talking about damaging the compressor if the system is over pressurized with R134. There is a tag under the hood noting the system was "converted" to R134 but I really don't know what was done or should have been done to do it correctly.
Thanks again,
Gene

R4 compressors (yours) are notorious for shaft seal leaks. Use a double lipped seal. Special tools from Autozone are free loaners for the job.

If you do get a compressor, try to get a new one, as many of the chain store rebuilts R4's are suitable as anchors for a skiff.