Peter Frederick wrote: > Speaking of pressure vs flow, I remember hearing that in the 70's, Alfa > Romeo had big warnings in their owner's manuals about not exceeding > 2000 rpm until the oil pressure came down off the peg at idle -- seems > that oil in those days was viscous enough at low temperature that there > was essentially no flow to the cams until the engine warmed up, and if > you ran the revs up to 6000 cold the cam lobes wore off pretty > fast..... >
Even my '89 VW Cabriolet has a note in the owner's manual to avoid high RPM until the oil temperature is over 50 C, which corresponds to the bottom peg on the oil temperature gauge. I seem to recall hearing that some cars had a three-state temperature light that would light up blue at cold temperatures to remind you to take it easy, but I can't recall which ones. Sometimes I wonder just how high the oil pressure in a Mercedes gets after a cold start. The gauges only go up to 3, of course, so we can't really know. My Cabriolet has a 5 bar pressure gauge and it usually pegs out on cold starts. I'm sure a Mercedes does even better.
