I've got an 87' 560SL and I am completely stumpped. The engine sounds perfect and is very strong. However, oil appears to be dumping out the exhaust. Here's what's going on.

I start the engine and let it idle for a few minutes. After the engine heats up, a HUGE cloud of blue/gray smoke starts pouring out the exhaust and will continue to do so for as long as I allow the engine to run. The engine still sounds great and idles like a champ. My first test was to start pulling the plugs to see where the oil is coming from. But every plug is clean and dry with no residual of oil anywhere. The firing of the plug (visual inspection) looks perfect.

Does anyone have an idea of how oil could get into the exhaust without any sign of oil being in the combustion chamber? I thought I would try plugging the EGR valve, but that made no difference. I'm at a complete loss on where to start looking or what to try next. Any ideas would be greatly appreciated.

Thanks,
-Tony-