I do not have the owners manual...1989 300te...I use Mobil One...Live in New York where the temps now are/ will be 10-50 degrees. Today it is going up to 50, but in a few weeks I suspect it will drop dramatically. I have Mobil One 5-30 in my garage for my Volvo...what is recommended for the 124 engine?

5W30 is not approved for Mercedes.

I'd stick with 0W40 or 15W50. Then again, for winter time only (<86F), the orginal owner's manual said 0W30 and 5W30 were useable.



Michael

__________________
Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

There are many brands of 5W30 weight oils approved by M-Benz:

http://www.whnet.com/4x4/oil.html

I have been using mobil 1 5W-50 for much of the car's life, and have switched to Castrol R 5W30 ( MB 229.3 approved ) lately to liberate more horsepower and throttle response from the engine. The vehicle has travelled 100,000Kms so far (60,000 miles)

It's summer in Australia now and the ambient temp often gets as high as 38-42C (100-107F) and I have no problem with the oil oxidizing at high temp. Just to make sure there is no abnormal wear on the bearings at high load in the summer heat, I have had the oil analysed. Results as follows:

Metals (ppm) -
6 Aluminium (Al)
2 Copper (Cu)
<1 Chromium (Cr)
17 Iron (Fe)
3 Lead (Pb)
<1 Tin (Sn)
Contaminants / Additives (ppm) -
3 Silicon (Si)
<1 Sodium (Na)
Physical Tests -
<0.05 Water (% by crackle)
79 Viscosity (cSt,40°C)
< 20 PQ Index

"All wear levels appear within acceptable limits for first sample. Silicon level (dirt/sealant material) satisfactory. Water content
acceptable. Fuel dilution satisfactory. Please check recorded viscosity against requirements.
Action: Resample next service interval to monitor and establish wear trend. Note: Oil type stated as, Castrol R 5w-30"



The oil has done about 9000Kms and the cSt@40C is 72.5 new according to Castrol Aust's spec sheet, so it has only thickened a fraction and still a 5W grade.

I will be trying the 0W40 at the next oil change. Switching from 5W50 to 5W30 has made a definite improvement on throttle response on small throttle openings. Fuel economy improvement on this car has been very minimal. The same oil in my BMW E30 325i has made a definate 3-5% improvement in fuel economy along with better throttle response.

Not sure if this is helpful,

But I have noticed when you switch an engine over from dino to synthetic(my older car), there was increased wear initially. So, I would try and find a brand to stick with.

I'm not sure what castrol is using in Aus, but in the USA they use group III base stock. That's the grip with the castrol product is they charge like it was a group IV/V oil instead of a group III.

I purchased Mobil 15W50 last night, and it says MB spec 229.1 approved. Funny, I thought it was approved for 229.3?? Same stuff my dealer uses....


Michael

__________________
Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

AUS-C36, I gather that the Castrol R 5W30 you used is completely different from the legendary Castrol R 30 and 40 which was synthetic and vegetable based.

__________________
Dan
1998 C43