scottamg

Just curious what you guys do as far as changing your oil ( every 10,000 miles like the local dealer suggests or every 3000 miles). Also, I have a minor leak in my differential that the dealer says to repair for about $900 but 2 other Mercedes shops said that it is a very minor leak and is common and not to fix it at this point. What do you think?

Lovemy420

I have seen a wide variety of responses on mercedes forums about the frequency of oil changes with a range of 3000 to 15000 miles. Most of them use synthetic oil with Mobil 1 being favored by many. I use a 50/50 mixture of Mobil 1 10W30 and 15W50 in the summer and 5W30 and 15W50 in the winter (I am in desert climate with temperature ranges from 10 F to 110 F). I change my oil every 7500 mi.

E-Klasse

I have never heard of mixing different weights of oils. Maybe it is different for Mobil1 but most oil manufacturers specificly say not to combine oil weights. Where did you get your information on doing that and what weight are you hoping to create?

If you want extended oil change intervals, use AMSOil. Then you can change it at 10K. If you use Mobil1 go to 5K. Conventional oil goes to 3K. It also depends on your driving habits and where you drive most.

I wish car engines would have timers in run hours like boats do. It would be better to gauge your oil changes on run hours instead of actual miles driven. This would capture idle time and stop and go trafic.

paomien

Petro-Canada synthetic 5w30 every 5,000 miles

C280Sportster

Check out the numbers on mobil 1 0w-40 it might be the perfect oil for you, if not year round, at least in the winter.

E-Klasse

This chart shows a rough guide to ambient temperatures vs oil viscosity performance in both multigrade (top half) and single grade (lower half) oils.
Multigrade oils work by having a polymer added to a light base oil which prevents the oil from thinning too much as it warms up. At low temperatures, the polymers are coiled up and allow the oil to flow as it's low number (W number) indicates. As the oil heats up, the polymers unwind into long chains which prevent the oil from thinning as much as it normally would. The result is that at 100°C, the oil has thinned only as much as it's higher rating. Think of it like this: a 10W30 oil is a 10-weight oil that will not thin more than a 30-weight oil when it gets hot.

If you think your car is ever likely to see a cold morning in the -45°F (-43°C) range, you should be considering 0W40 oil. If not, 5W40 will do. 0W and 5W oils don't flow any differently the 0W will be pourable at a much lower temperature. They are made from the same base oil.

You should just use 5W30 in the winter months and 15W40 in the summer months.

E55AMG99

Mixing oils? Don't do it. Synthetics have a wider range than 10-110F so it is not necessary.

At your next oil change, take a sample to an analysis lab. They can tell you how dirty the oil is and how much acid it has picked up. This information (with the oil's TBN) will help you determine what is appropriate for your driving habits.

I did this on my E55 at 5,000 miles on the clock and the oil was at the lower limit (good) on acid and in the middle of the acceptable range for silica (dirt) and metals. Based on this information, I change my filter at 5K and my oil at 10K. The analysis at 10K was higher in acid but still OK and about the same silica and metals.

Lovemy420

Thanks all for your information, with special thanks to E-Klasse for his informative graph. Translating the Centigrade into Fahrenheit, the chart says straight 15W50 has good viscosity in the range of 35 to 86 F. Based on this, I should be using at least straight 15W50 during the hot summers, and 10W30 in the winter. In fact, now I wonder if 15W50 is heavy enough for my 100+ summers. Anyone have any suggestions? BTW,E55AMG99 what is TBN and where would I find an analysis lab?

E55AMG99

15W50 might be too heavy. Check the manufacturer's recommendation. Isn't it something like 0 or 5W30?

I just went to my local Jiffy Lube (with very careful observation and instruction) to have a sample drained off. The mailed it and reported back to me in about 10 days.

TBN is total base number. Base being the opposite of Acid or TAN for Total Acid Number. Base or low in acid is how oil is in the bottle. Over time, it picks up acids from the combustion process and becomes acidic. If it gets too acidic, it loses effectiveness and casues harm to your engine.

E-Klasse

I just use 10W-30 all year here in Arizona. I could go to 10W-40 but I don't want the range to wide from the cold pour value to the hot value or there will be more polymers in the oil. I was told too never to go above 40 weight and I have heard of people finding leaks with too thin of oil with 0 or 5 weight or if they switch to synthetic oil. 10W-30 has been good for me.