Does anyone know what the differences are in the US 2.0L and the 2.0L used in Europe? I only ask because of the different oil weights used here vs. what is used in Europe.

 

Europe has different emissions requirements such as gas particulate regulations.

 

So in reality we could run a heavier oil and the engine will be fine?

 

What are you trying to accomplish by using a different oil?

 

A value that matters more than "the weight" is the HTHS (High Temperature High Shear) value. This value is the viscosity measured at 150C, which is much higher than the standard 100 C. The higher the HTHS, the greater the minimum oil film thickness (MOFT), and the higher the MOFT, the less reliance upon anti-wear additives to keep parts separated when conditions (temperature and pressure) are trying to thin the oil to the point that metal-to-metal contact occurs.
The lower "the weight", the better the anti-wear agents need to be. There are some 20-weights with higher HTHS values than some 30 weights, but the MOST important consideration is the function of the END PRODUCT. There are many 0w20's that protect better than some 40 weights due to superior anti-wear materials used in the 20 weight...and there are differences in how the 20 or the 40 are achieved...some 40's need viscosity index improvers to reach the range of 40 weights and there are VII's that are more prone to shear than others.
Oil mixing is a science. The end product is much more than "the weight", so don't make decisions based only on "the weight".

 

You can typically go up one level in oil weight without much issue. Example, going from 5w20 to 5w30, or from 5w30 to 5w40. The second number is the hot viscosity level.

Depending on where you live, I would suggest not going up on the first number, such as going from 5w30 to 10w30. The first number is the cold viscosity level. Going higher makes the oil thicker when cold, and could cause cold start problems.

 

I was just wondering what the reasoning behind the difference was, why use a thicker oil vs a thinner one on different continents when it is the same engine, that's all.

 

Then "increased MOFT" is the simplest answer. "MOFT is not the most important factor" is an important qualifier.

 

Thinner oil is usually spec'd in the US market due to fuel economy values. Thinner oils will aid in slightly higher fuel economy.