Have just bought an E430T (estate/station wagon) 3.5 years old with 90K miles, to replace my E280T.
I didn't realise what the gearing was like on these - just over 2000rpm @ 70 mph.
After taking delivery of this one owner "motorway mileage" machine, I decided to boot it
As the revs approached 5000rpm, a load of smoke came out of the back

I thought - s@@t I've bought a dog
Anyway, when I booted it a few more times, it seemed to clear. Does this just sound like old fashioned carbon bulid up in the heads ? My dads old V12 Jag needed clearing every 4000 miles but I didn't think modern engines would retain all that cr@p in the heads ? Is it possible that the previous owner that has done these 90K miles has just sat there @ 2000rpm on cruise ? If this is likely then does this mean the engine should be in better condition than a regualrly thrashed one (of the same mileage) ?