I got an oil change today, and my mechanic put in 10W-40 (Castrol GTX), I've been using Castrol GTX 10W-30, for a while, and now the mechanic went the the change.. My question is--what viscosity should I use? I know this topic has come up milions of times, and I know it has to do with the climate conditions, and your driving habits. Im not a rough driver, and I drive mostly highway miles back and forth from school. Here in New York, we have cold winters, and hot & humid summers. Which viscosity should I use in the winter/summer??

P.S. I do not use synthetic

Thanks in advance...

Agron
1989 300E (105k miles)

I use Castrol GTX 10W-40 in all of my cars (except the 380SE, that gets Mobil 1 10W-30 synthetic, but used GTX 10-40 up until the switch). I like Castrol products very much and do 500+ miles a week of highway driving and find it to work fine. I just keep the 10-40 in all year and even in my Turbodiesel, I have no hard start problems in the coldest of winter and find that Castrol oil does pump very quickly at low ambient temperatures. So I would advise you stick with the 10-40. Good stuff. BTW, the only reason I switched to synthetic in the 380 was because I was so thrilled that I caught the broken timing chain rail in time that I figured I needed to begin treating her with the best out there. Besides, I don't drive her that much so there might as well be the best oil possible in there!


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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'85 BMW 745i Turbo

Do what Aaron says...guys usually right (how else could he keep his fleet on the road, especially the Jensen!?!) and is spot-on this time!

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Best regards, Michael
'92 500E
'88 300TE

When I purchased my '82 300SD it came with extensive maintenance records. One of the service shops had written "no mulit-grade, use 30W only". The shop has a reputation in San Antonio as being one of the best places to have your Mercedes serviced, if you love her. Could this be correct? What is best for the turbo?

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'89 300E 3.0
'82 350SD

I've lived in Texas all my life except for a few years in the Army. (Hear that y'all?)

I started using multi-grade oil only a few years ago. I ran 30W winter and summer for years, changed it often, and my engines ran for a long time, and the ones I took apart were clean and looked good, no cylinder wall scuffing, or bearings looking bad.

My Grandfather was a rancher near Blanco, which is not far from San Antonio, he used 30W in machinery and road vehicles exclusively, and ran them until they fell apart, which took a long time because he cared for everything well. He never used anything but 30W.

It is rare for the temperature to fall below 20 degrees F. and REALLY rare for it to get below 10. If there was ever any damage that may have been done at 10 or 20 must have been minimal.

All that said as testimony for straight 30W, the multi-grade oils have improved so much, it doesn't seem to make sense to use single weight any more. Regardless of your favorite brand of oil, and I'm certainly not going to open up the oil "brand" can of worms, there is a good multi-grade oil available. Just stay away from the ultra wide spread in winter/summer grade, such as 10W40, or I even saw a post about 5W50.

San Antone is a warm climate, but there are very good multi-grade choices. If it were my luck, I would put in 30W and have a record breaking blizzard come through.

Good luck,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

I've used straight 30W Pennzoil with no problems. The best advice is to change it often, no matter what you use. You'll never have problems (oil related) with the engine if you follow this simple advice, which has been given to basically everyone. Oil changes are cheap engine insurance..

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Jeff L
1987 300e
1989 300e
1987 BMW 325

I recommend 10W-40 in the winter and 20W-50 in the summer, especially if you find that you are burning a little more oil than desired.

Mobil 1 makes a 10W-50 synthetic, good stuff, just $4 / qt.

Ride on

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'89 420 SEL
'90 300 SEL
'84 300 SD (sold it)