Hi

1983 300sd 125,000km or 80,000 miles

Problem:

Rattling noise from front of engine when climate control off or on economy mode. Noise stops when normal or defrost AC modes selected.

How I think I caused it:

I changed the power steering fluid on Sunday, and filter, and purged. Sure needed it - the old filter had separated into three separate parts! When purging I forgot there was a hole in the side of the reservoir as I'd removed the low pressure return hose, and I managed to pour about a cup of ATF through the hole! Stupid, I know......

I assume that the black cylindrical thingy driven by a belt that is below the power steering pump is the AC compressor? And I managed to ATF all over it. Yuk.

I saw one old posting when searching that reported similar noise when the AC was disengaged, and that was due to insufficient belt tension. Do you think that ATF over the belt could cause the same issue? But why when disengaged?? I've always had previous compressor problems when you engage the AC, NOT when you disengage it!

Thanks in advance.... RL