I just got a case of Synthetic 5w-20 motor oil for free. I was wondering if this was ok to use on my G. I usually use 5w-30, but was wondering if using the 20 grade was bad for my car.

Thanks guys.

Twilight Blue G35 Coupe 6MT
Premium - Nav - Aero - Trunk Mat
Injen CAI

 

I would only use something that low in viscosity during the winter months. If you plan on it getting warmer than 70 degrees outside, I would save it for January. If you live in the south or southwest, stick to 5/30 in the winter and 10/30 in the summer. Never use the ultrawide 5/50 or thick 15/50, 20/50 in this engine, too many viscosity modifiers in the 5/50 and the VQ bearing clearances are too tight for 20/50 and possibly even 10/40.

 

It gets about 90-100 in the summer here. If I did put it in, what could go wrong? Engine overheat or less performance?

Twilight Blue G35 Coupe 6MT
Premium - Nav - Aero - Trunk Mat
Injen CAI

 

The oil may thin too much to lubricate properly. If that happens you'll score bearings and cylinder walls...UGGG
Stick with 5-30 in the hot months, and use the 20 in colder months.

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