M112 C320 V6 engine oil 10w40

[Merclover2005]

Hi all,

Have just had my V6 C320 coupe serviced and the garage I used put 10w-40. I've seen o line that most people say to use 5w-40 for this engine. Will the oil they put in be okay or shall I get it changed as I'm really not sure what to do? Baring in mind I'm in it's turning to winter in the UK so want to make sure I have suitable oil for that weather.. I also have noticed the engine sounds slightly more noisy since they've put this oil in. I cannot tell if this is my own paranoia or if its due to the oil being too thick?
Can someone please help and advise me on this matter?

Thank you,
M.

 

[Gazwould]

5W40 better basestocks , better protection , better start up cold flow .

 

[Accused]

Probably semi synthetic if 10w40 to, it will do no harm but I'd go with 5w40 fully synthetic and an oem or Mann filter if it were me

 

[Merclover2005]

5W40 better basestocks , better protection , better start up cold flow .

Okay right I understand. I have no idea why they didn't put that one in then . My question is though, will the 10w-40 be okay to leave in the car for a whole year without causing any issues until my next service or shall I get the oil changed to 5w-40?

 

[Merclover2005]

Probably semi synthetic if 10w40 to, it will do no harm but I'd go with 5w40 fully synthetic and an oem or Mann filter if it were me

Ah okay I see. If you say it should do no harm then hopefully it'll be okay. I just don't want to leave it in there if it's not good for my engine that's all.

 

[Bellow]

Okay right I understand. I have no idea why they didn't put that one in then . My question is though, will the 10w-40 be okay to leave in the car for a whole year without causing any issues until my next service or shall I get the oil changed to 5w-40?

It will be fine. Just be gentle for the first minute or so from cold start. Within a couple of minutes of running it will be the same viscosity as the 5W-40 would be and from there on no difference whatsoever.

 

[Gazwould]

Except it won't be the same viscosity after a few minutes !

 

[Merclover2005]

Except it won't be the same viscosity after a few minutes !

See this is why I'm getting confused. As there are so many different opinions on the matter.

 

[Gazwould]

Tell me what actual 10W40 went in and then select an actual suitable 5W40 and I'll show you , preferably not the genuine Mercedes oil as I doubt they disclose .

 

[Merclover2005]

Tell me what actual 10W40 went in and then select an actual suitable 5W40 and I'll show you , preferably not the genuine Mercedes oil as I doubt they disclose .

I have no idea it just says '10w-40 engine oil" so I'm not even sure which oil.

 

[Merclover2005]

Tell me what actual 10W40 went in and then select an actual suitable 5W40 and I'll show you , preferably not the genuine Mercedes oil as I doubt they disclose .

I've just called them and he said they basically send off the reg and the supplier sends them the oil they think is recommended for that car. I've spoke to my usual mechanic from London and he firstly said that they only use that oil for cars that have done high milage and mine has done 50,000. Which is not even broken in for that engine it's practically close to new. He also said that oil is not the recommended oil to use by Mercedes and it could be causing the increased noise from engine when driven hard.

 

[Tonye]

Google Image Result for https://media.noria.com/sites/Uploads/2015/7/22/cf028082-9c32-408b-9922-6c55c0d2dc53_SAE%20chart.jpeg

 

[190]

To help you visualize the difference between 5W40 and 10W40 here is a graph of oil viscosity vs temperature for a number of different oils. 15W40 and 20w50 are vastly thicker when cold but the difference between 5w40 and 10W40 is small and not worth worrying about in a temperate climate. Frankly I'd have been more concerned about the quality of oil that they used i.e. does it meet the appropriate MB spec.

 

[Accused]

If my merc has only 50k it would be getting merc oil or at worst a good brand of exactly the right spec.
Mercedes genuine 5w40 £48 10l eBay, mann filter £13. DIY for just over £60 with total peace of mind

 

[Merclover2005]

To help you visualize the difference between 5W40 and 10W40 here is a graph of oil viscosity vs temperature for a number of different oils. 15W40 and 20w50 are vastly thicker when cold but the difference between 5w40 and 10W40 is small and not worth worrying about in a temperate climate. Frankly I'd have

Thanks for the graph. I have asked them exactly what oil they've put in the car and I'll then decide whether to change it or not.

 

[m80]

Thanks for the graph. I have asked them exactly what oil they've put in the car and I'll then decide whether to change it or not.

If / when you have the brand you should be able to check via Google if it meets the MB spec for your motor.

 

[Bellow]

5W40 better basestocks ,

Evidence please - or at least an explanation.

better protection

Protection from what?

, better start up cold flow .

Marginal and really not a problem unless London regularly experiences minus 35C.

Except it won't be the same viscosity after a few minutes !

So what will it be? How long do you imagine it takes oil being vigorously pumped around components being subjected to combustion heat to gain 5 degrees C?

Tell me what actual 10W40 went in and then select an actual suitable 5W40 and I'll show you , preferably not the genuine Mercedes oil as I doubt they disclose .

Show what?

 

[Tonye]

As long as its low sulpher it will be fine unless you are planning a road trip across siberia this winter.

 

[Tonye]

With 50k on the clock it will do more good than bad

 

[Merclover2005]

If / when you have the brand you should be able to check via Google if it meets the MB spec for your motor.

I'm just waiting to hear back from them still. So I guess if they've used a MB approved oil I can just leave the 10w-40 in there. If they don't confirm exactly what oil they've put in I'll change it anyway. I'm not taking any risks and would rather pay for more oil than to have issues down the line.