Just bought at 2006 E350 4Matic with 27K miles 2 weeks ago and now second owner. What is the recommendation for warming up the car in cold temp's? (Philly area) My background is heavy duty diesel engines where we apply jacket water / lube oil heaters, battery heaters etc. for quick start.

The car has neither but would like to know if there's anything wrong with warming up the engine until the interior heater shows some heat?

Second, I also hear mix opinions on hi-test gas vs. using regular gasoline. Any strong opinions on not using hi-test?

asuperglide, follow the recommendation of your Owner's Manual regarding grade of gasoline ... most likely premium, 91 octane. As for warm-up, the fastest way to warm up the engine is to start the engine and drive conservatively until up to operating temperature. Any other process merely wastes fuel. MB automobiles have an auxiliary water pump that allows the climate control system to produce heat very quickly.

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Fred Hoelzle

Agree with Ferdman. Warmup under light load is good for any engine. Idling for a long period while warming up will only promote condensation.

IRT fuel, use premium. The difference in cost is minimal and your engine will thank you for it by running cooler and never predetonating. You will also preserve whatever warranty you may have if any.