Synthetic oil in high mileage

[C250TDSportAuto]

I'm thinking of changing the oil in my C250 TD with 150k+ on it, but seem to recall reading that you shouldn't put synthetic oil in high milege engines, as it can soften gaskets/seals etc. Had a search on these forums and can't find it here. Can't remember where i read it. The previous owner had been recommended and had used 15w40 mineral based.

Is there any truth in this?

I'm completely baffled by oils and oil labelling. Would it be safe to change to synthetic, if so which viscosity/brand, or should i stick with the 15w40. I'm sure the owners book says to use a 10w40.

 

[stringerdavid@hotmail.com]

Best to stick with Magnatec

 

[malcolm E53 AMG]

Use a good semi-synthetic if you change the oil regularly ie once a year and do less than 9K. Synthetic oil is very expensive but if your doing 15-20K a year worthwhile.

 

[Parrot of Doom]

It won't soften any seals, but it may reveal leaks which already exist. Better to find those leaks and fix them, then to use cheap oil to hide them.

I use fully synthetic in mine, and I'm on 188,000 now. Mobil 1 0W-40.

 

[Pipemaster]

Mobil 1

It won't soften any seals, but it may reveal leaks which already exist. Better to find those leaks and fix them, then to use cheap oil to hide them.

I use fully synthetic in mine, and I'm on 188,000 now. Mobil 1 0W-40.

Mobil 1 is blinkin expensive to fit but worth every penny for peace of mind and it means you dont have to change so often....

 

[C250TDSportAuto]

Cheers for that.

I've had a read of this post by oilman http://forums.mercedesclub.org.uk/showthread.php?t=28241 and now i'm even more confused

Does anyone have any views on Halfords fully synthetic 5w40. it meets MB 229.3 and API SL CF ACEA A3 B3 B4 and is BOGOF at the moment. It also says it is suitable for use in the latest turbodiesels. Not sure if it's suitable for use in a 10 year old TD though. Does anyone know who makes this oil.

Any thoughts.

 

[wscheffer]

I think that 5w-40 is too thin for an older car, unless you are trying to find leaks I would stick in the 10w to 15W range.

 

[Parrot of Doom]

If it meets the spec it will be fine. If you have a trade, join Costco - Mobil 1 is £20 + VAT for 4 litres. Put the best oil you can afford into your car, it will pay back.

 

[230K]

Hi

254K Mobil1 5w 40 for the last 100k that i know about no leaks.

230K

 

[television]

MB are going over to Shell now