The 300E I recently purchased had just had the head gasket replaced and the valve train re-done. I got concerned the other day when I opened the cap on the recovery tank and saw that milkey brown crud in there.

I called the guy who did the work and he said it's fairly common for it to collect there and he'd flush it for me if I brought it in. I decided to take care of this myself since he'd not used MB coolant.

I removed the recovery tank and after a couple dozen attempts to flush it clean, I decided to buy a new one. I was encouraged when I drained the radiator and block that the coolant showed no signs of contamination. So, I flushed the system and re-filled it with MB coolant. The next day, only a tiny dab of the brown coolant was stuck on the bottom of the cap. Today, there was nothing, so I think I got it sorted out.

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Mr. BILL

91 300E 120K
90 300SE 275K (sold)
92 BMW 525iM 120K
90 BMW 525iA 175K
85 300D 175K (sold)
84 300SD 245K (sold)