what if i use a heavier kinematic viscosity?

[mrendiadi]

hi guys, i have a question..i have a European Civic turbodiesel with an idtec 1.6 liter engine. the recommended oil would be a 0w30 with a kinematic viscosity of 10.3 at 100c and 55 at 40c. indeed these are the values of castrol 0w30 professional H, an oil engineered in collaboration with Honda especially for the idtec engine.
my questione is, what if i use an oil with the same grade but with a heavier kinematic viscosity? for example, i would like to switch to mobil1 esp 0w30 which has 12.2 at 100c and 72 at 40c? will i have problems with my engine? or the difference concerns only the mpg per liter?

 

[chrisri]

Nothing will happen because difference in KV100 isn't that great between oils you've mentioned. Noise reduction is possible.

 

[ExMachina]

MPG fuel economy will drop going to the higher viscosity, and the 1.7 cSt difference in kv100 means about 1% difference in fuel consumption, assuming the friction modifiers (FM) in Mobil1 vs. Castrol there are comparable. Actually the Castrol may have more FM since its designed to be a lighter kv100 oil and designed for greater fuel economy.

If you don't mind the ~1% fuel economy drop going to the Mobil1, the vehicle will be OK since both oils are ACEA C2 and both quality products.

I'd stick to the Castrol, since you'll get less wear at start-up with the lighter oil, and Castrol has worked with Honda to create something maybe special.

 

[volodymyr]

ExMachina,

Originally Posted By: ExMachina

I'd stick to the Castrol, since you'll get less wear at start-up with the lighter oil


Same assumption would also be true for SAE viscosity? I.e., with 0W-30 you will have less wear on start than with 5W-30 assuming the same ACEA specifications and not severe cold temperature (let's say -15C max (5F)?

 

[ExMachina]

Originally Posted By: volodymyr
ExMachina,

Originally Posted By: ExMachina

I'd stick to the Castrol, since you'll get less wear at start-up with the lighter oil


Same assumption would also be true for SAE viscosity? I.e., with 0W-30 you will have less wear on start than with 5W-30 assuming the same ACEA specifications and not sever cold temperature (let's say -15C max (5F)?


If temperature is over about 20 degF, there is almost no diff between startup wear on a synth 5w-30 and 0w-30 I'd guess. Below about 20 degF, you begin to get some benefit from using a 0w-30 usually. It depends on whether that 0w-30 is the thicker kind such as an MB 229.5 oil, or the thinner M1 5w-30 dexos1 oil, so it does depend. Oil is always too thick cold no matter what kind it is, so its just a matter of trying to reduce the thickness cold down as much as possible.

 

[Garak]

Perhaps looking at the HTHS of the two oils might be more useful. Then, if they're the same, a higher VI would likely give better fuel economy.