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Discussion Starter #1
i currently have shell 15w-50 in my 147 1.6TS. is it ok to mix it with 5w-40 of the same brand? what about mixing with other types of brands?
 

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Well, its best to use the same specification of oil for your car. If you use one that is too thin you can increase oil consumption, too thick and it may not give you the necessary protection. However, mixing brands isn't too much of a problem, providing they are both a good quality.
 

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As said above, you can mix almost any modern oil.
However, neither of those oil is the correct grade for that engine!
 

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David C said:
As said above, you can mix almost any modern oil.
However, neither of those oil is the correct grade for that engine!

5W-40 should be ok in that engine as a 10W-40 is specified. It is the same viscosity when hot.

I wouldn't mix 2 different viscosities though. ;)
 

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symonh2000 said:
5W-40 should be ok in that engine as a 10W-40 is specified. It is the same viscosity when hot.
Yes, but it is a different viscosity when cold!
It is just about ok though as they spec a 5w30 for extreme cold climates, so the oil pump can take a 5w oil.
If you drop to an oil that is too thin then the oil pump can't pump it any more and you loose oil pressure, not good!
So stay well away from any of the 0w oils, they exist to reduce emissions on startup, not to help protect the engine!
 

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Discussion Starter #6
nothing much i could do. the agent over here did not carry 10w-40. they only have 15w-50shell or selenia 10w-60. i suppose u could go higher than 40 but not lower. also, they insist i must use their given oils so i went with shell thinking i could get it anywhere. but when i checked out the petrol stations, they are actually carrying only 5w-40. guess i gotta go back to the agent to get that 15w-50.
 

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David C said:
Yes, but it is a different viscosity when cold!
It is just about ok though as they spec a 5w30 for extreme cold climates, so the oil pump can take a 5w oil.
If you drop to an oil that is too thin then the oil pump can't pump it any more and you loose oil pressure, not good!
That doesn't make any sense, does it? If the pump can't pump the oil when cold because too thin, what will happen when the oil heats up, and it gets thinner again by a factor 10?

Regards,
Cuore_Sportivo_155
 

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Cuore_Sportivo_155 said:
That doesn't make any sense, does it? If the pump can't pump the oil when cold because too thin, what will happen when the oil heats up, and it gets thinner again by a factor 10?
I think a different method is used to calculate the two.
Try a 0w oil if you want, but keep plenty in the boot as you will need to top it up very frequently.
 

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trento said:
nothing much i could do. the agent over here did not carry 10w-40. they only have 15w-50shell or selenia 10w-60.
Selenia 10w60 is also spec'd for that engine, so would have been the right choice.
 

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My cars doesn't use any oil since I started using the 5w-40 fully synthetic, whereas with 10w-40 selenia it did use a bit. I don't really think there would be much problem using a 0w-40 TBH with respect to oil consumption, although you may find it leaks out of the variator more when the car is stood, hence you may get more rattles on a startup.
I did read also ( a post by oilman) that a 10w-40 fully synthetic will give far higher film strength ( and protection) than a 10w-60 mineral of semi synthetic oil, therefore if a 10w-40 mineral is specified a fully synthetic 10w-40 will be more than adequate. A thicker oil casue more drag which creats more heat and more wear, as well as overloading things like oil pumps.


The only reason Alfa specify the 10w-60 on the later engines is to cut oil consumption. This was due to people not checking their oil and running the engine low by accident.
 

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David C said:
I think a different method is used to calculate the two.
Try a 0w oil if you want, but keep plenty in the boot as you will need to top it up very frequently.
a 0w-40 oil, even being a full synth, will be doped quite a bit with viscosity improvers. These are widely known to be with the first dopes that fail in any motor oil engine, resulting in what will likely be closer to a 0w-30 oil. Obviously this isn't the right viscosity at all anymore (10.9 cSt average for SAE 30, 14.4 cSt average for SAE 40). That would obviously cause quite a bit of consumption.

Regards,
Cuore_Sportivo_155
 

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trento said:
nothing much i could do. the agent over here did not carry 10w-40. they only have 15w-50shell or selenia 10w-60. i suppose u could go higher than 40 but not lower. also, they insist i must use their given oils so i went with shell thinking i could get it anywhere. but when i checked out the petrol stations, they are actually carrying only 5w-40. guess i gotta go back to the agent to get that 15w-50.
I would be questioning them as to why they insist you use their oils when one of those oils has the wrong viscocity for the engine. I don't know what your climate is like so I may be off, but I would dump the 15w-50 and fill with a 10w-40 of a brand which is readily available, or selenia 10w-60 if you are going to use the same people next time.

Also, IMHO although you can mix oils, I would expect that this reduces the properties, espcially if you mix both viscocities and brands :(
 
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