Up oil weight with high mile engines?

[f355spider]

Funny how Ferrari , Porsche and Lambos run such high viscosity oils to help their engines.

Ferrari almost exclusively uses 5W-40...the only exceptions are a few of the V12s in specific models and years where 10W-60 is recommended.

 

[Javed]

Why do they say to increase viscosity when engine gets old?

 

[george1122]

...For me though, a small increase in fuel consumption is an easy trade off when I consider that fuel dilution is a factor in engines such as the EA888 in my Tiguan, and that it is turbocharged. I'll gladly trade that extra fuel for the protection that an oil like ESP 30-grade brings...

Send off some used oil to one of the labs that do oil analysis. The analysis will tell you if you have excessive fuel dilution, which can be caused by a leaky fuel injector or too long oil change intervals.

 

[Carlostrece]

Why do they say to increase viscosity when engine gets old?

Some say to do that when engine is worn. Others say not do. Personally, I think it depends on the situation, but in specific situations I'm in favor of increasing the second number (after the w) by one grade. I like to leave the first number (before w) at stock number.

Increasing 2nd number increases viscosity at full op temp, which reduces oil leaking and oil. However, I think increasing op temp grade/viscosity should only be an option of last resort (if other easy cheap fixes have failed). Also, I personally would only increase by 1 grade, not more.

Others may have different opinions.

 

[kschachn]

Send off some used oil to one of the labs that do oil analysis. The analysis will tell you if you have excessive fuel dilution, which can be caused by a leaky fuel injector or too long oil change intervals.

Thanks, I have done that. Unfortunately it is common to this engine.

 

[cheesepuffs2]

Oil viscosity is not a “weight”. That’s something that is misunderstood by many people, including on here. They are grades.
So the proper term would be to say 30 grade, not 30 weight.

I don't think it's "misunderstood", it's just a colloquialism.