I don't know if my 01 CLK 430 has synthetic or reg oil & am ready for an oil change. What oil do you recommend to use?

read the owners manual!

Mobil 1 SuperSynthetic 0W-40. (8 liters = 8.45 quarts)

TresX, thank you very much, exactly what I needed to know.

nov0798, don't appreciate the arrogant answer, if it was in the manual I wouldn't have to ask. The manual states: use approved fluid's.

Idle Swede, the oil capacity of your car is nearly certainly listed in the Operator's Manual. For my car, it is towards the back of the manual in the Technical Data Section.
If you want lots of opinions on motor oil and oil change intervals (OCI), go to the oil forums at www.bobistheoilguy.com That is where the motor oil fanatics are located.
William
2003 E320

You won't hurt your car by using synthetic but if your car expects synthetic and you use normal oil then you probably will.

Two people you don't know gave you advice on the internet and the one that gave you the best answer you chastized. Actually, I agree with TresX but not because I know, I just think, it's correct. If it matches the owner's manual (Factory Approved Service Products) then I would be sure.

i say if you are thinking of going synthetic, do it expecting to pay the extra at EVERY oil change from NOW til FOREVER. No point in putting in good oil now, if you will cheap out later.

I'm not saying that you are going to do the above, but I just figured it needed to be said.

In our family cars, I personally run Mobil 1 10/30 (129 SL600 and SL500) In the 420SEL I cheap out slightly and use regular Penzoil 10/40. But my dad's Diesel 300TD, he runs 20/50 castrol synthetic, but the oil in that car gets changed on average every 3 years. :p

I pay $37 for my oil change with Mobil 1 Super Synthetic and OEM Mann Filter.

Idle Swede

Check this link out. Your would qualify for 229.1 and later
http://www.whnet.com/4x4/oil.html

JeffreyP