correct oil for high mileage merc

gbv

Member
E220 cdi avantgarde - automatic diesel. Has covered 105,000 miles.
One mechanic says with a higher mileage car I should use 15W40 semi-synthetic oil. It is better for a high mileage vehicle than the one specified - which could damage the engine. Another mechanic friend disagrees. He says I should stick to the recommended Oil - High mileage should not affect the Oil required.

Any views on this ???

Also is fuel economy affected by which Oil is used ????
 

umblecumbuz

Senior Member
And to answer your second question - yes, fuel economy is affected by the oil used.

Ask a professional 'economy run' driver. When they prepare their cars,they drain all the oils and put in extra-thin stuff - gearbox, rear axle (if there is one!), wheel bearings, engine etc.

But that's extreme. In every day use, any minute difference between, say, 5/40 and 15/40 is ignorable.

Baz
 

Alex M Grieve

Senior Member
E220 cdi avantgarde - automatic diesel. Has covered 105,000 miles.
One mechanic says with a higher mileage car I should use 15W40 semi-synthetic oil. It is better for a high mileage vehicle than the one specified - which could damage the engine. Another mechanic friend disagrees. He says I should stick to the recommended Oil - High mileage should not affect the Oil required.

Any views on this ???

Also is fuel economy affected by which Oil is used ????

Hello and welcome to the Forum.

As others have said, stick to the specified oil. Fully synthetics are extremely durable, easily outlast the oil change intervals we tend to give them, and provide excellent lubrication.

MB (and most manufacturer's) handbooks usually give excellent advice on the use of their vehicles in extreme conditions, and how to vary the schedule for filters and lubricants. I am sure if they felt that a change of lubricant specification was advisable with higher mileage, they would specify what change was to be recommended and at what mileage.
 

jberks

Senior Member
I'm running the standard stuff in my 130k E270.
I suspect that mechanic was 'old'?
It used to be a practice to change oils at higher mileages many years ago but not any more afaik. Wear rates are much lower than they used to be. In the old days with 100k on the clock you'd be expecting a major rebuild imminently. Now, most of us have more than 100k on our cars. So, would I change the oil type on a low mileage one like yours? No, just stick to good quality 229.3/5
 

st4

Banned
As above really. I use 0w40 Mobil 1 in my 112,000 mile car.

Very good spec oil C. I would not use a 15-40 oil. Clearly as most engine wear is done when the car is cool, you want an oil that has a low vicosity when cold. The 0w part of the mobil one formula ensures this. At 15w its probably too viscous for cold weather cold engine protection. The 40 part ensures when the engine is hot, the oil does not go too thin that it loses its protective qualities.

In a climate like ours, we do need this. 5w-30 shell Helix is recommended for Mercedes cars and it doesn't have the operational range of Mobil 1 )w-40.
 
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