I took my MBenz 1999 C280 for oil change and specifically asked for Mobil 1 synthetic 5W40 which I have always used. But they used 0W40 instead.
I understand that 0 is a thinner oil on a cold start. My question is will the 0w40 hurt or make it even better for the car? I am in Illinois.

 

The answer is no, it won't hurt anything. Better in the winter anyway. Mobil won't put our a product that wouldn't carry a warning label if it could cause damage.

 

You might do some research and check the MB spec for your 1999 C280. You might be surprised to learn that Mobil 1 ECF 0W-40 is actually the correct oil and 5W-40 is not. I'm not saying this is 100% correct — just saying is worth doing the research.

 

Thanks guys for the input.