CLK 320 - Oil - Synth or Semi-synth?

[lordlee]

Hi All,

I have been pondering my choice of oil for the CLK as the car is now nearing 95k miles and is using around 1/2 litre every 1000-1250 miles. I am unsure from when I bought the car whether it had synth or semi synth so I have been topping up with Mobil 1 229.5 spec. Now its time for a change and I am wondering whether putting semi in will reduce the amount of oil its using? Its that or stick with Mobil 1 and keep an eye on the top ups. Any suggestions please?

 

[grober]

A good budget 5w40 fully synthetic that meets MB 229.3 will be fine. e.g. Fuchs TITAN SUPERSYN 5W-40 High Performance, Fully Synthetic, Engine Oil

MB 229.5 is over spec and wasting money. Check you havn't got a major leak somewhere to be losing that quantity of oil.

 

[grober]

duplicate

 

[coupe deville]

£16.48 with free delivery with mbclub25 discount
TRIPLE QX 5w40 Fully Synthetic Engine Oil 5Ltr

you know it makes sense m,lud

 

[Howard]

That is a lot of oil to get through in that amount of miles , i would have a good look for leaks.

I popped 1/2 litre in mine the other day ( i do did it regularly ) , but i haven't put any in for over 5000 miles before that.

 

[lordlee]

I think the amount of oil is in correlation to perhaps mixing synth and semi and also I do a fair bit of high speed motorway (in Germany of course your honour). There are 100% no leaks as I keep the engine bay as clean as possible. I have checked underneath too.
It will be interesting to see whether the oil change will alter the consumption as I will know exactly what is in there.
Costco have a good deal on oil starting Monday so I will probably get some Mobil 1 as its only £20 or so for 4litres.

I was just wondering if anyone had changed their oil from synth to semi and seen the car using less of the stuff.

 

[lordlee]

Thinking more on the subject is it probably more like 1/2 litre every 2000-2250miles. Which is still more than i'd expect

 

[flango]

mixing semi and fully synth usually does have an effect of increasing consumption, don't know why but have seen it before. Whatever you go for next flush it before putting in the new oil, personally I'd go with a decent semi syn

 

[andy27168]

Hi,
I would say that sort of oil consumption is,nt anything to worry about IIRC correctly the handbook for the C43 says that up to 1litre of oil every 1000 miles is nothing to worry about, I know that mine is a 113 v8, but the 320 is effectively a six cylinder version of it.
Have you looked in the service book as the type and grade oil used should be written down.

 

[lordlee]

I know what grade etc to use from the handbook but I was more thinking of going down the semi synth route to lessen oil consumption on a higher mileage engine. It turns out, after chats to the guys at Opie Oils and a couple of local specialists, that synth is the recommended choice even for the higher mileage lumps. The semi choice would only be worthwhile if costs was a real issue. At £23 for 4litres (x2 obviously) its a no brainer for me. Specialists have said that the oil consumption is entirely fine and that it will be interesting to properly measure the use whne a full change and flush has been carried out.