MENTY

iTrader: (2)

Just got my oil change and they put 5/30 in, instead of 10/30. They are claiming to have a bulletin about the change, but still have not given me written proof. I know this weight can be used when its cold out, but its not cold out now. What should I do? BTW the change cost 63.00, but is included in my purchase agreement. Thats a bit excessive!!!

HuskerEVO

I actually prefer the 5w30. It has always been worth a little extra MPG for my other cars. I'm not ready for my first oil change.

There isn't much difference between the 5w30 and the 10w30 other than the 5 has slightly better cold weather performance. I used to use the 0w30 on my WRX when it was still available.

evo81

iTrader: (30)

it's ok

Ferb

Between 5w-30 and 10w-30 synthetics, there isn't too much of an issue. The smaller spread of the 10w-30 will theoretically have less viscosity index improvers-- molecules that allow the wider spread, but can shear and cause sludge.

But, as you can see in the few oil analysises on the board, 30wt might be a little thin. Especially in the Mobil 1 flavour of 30wt. Mobil 1 tends to sit on the low side of viscosity ranges. This can provide a bit better fuel economy, but does give the possibility of raising bearing wear. This wear is shown as increased lead, tin, antimony, and copper wear.

As for if it's "okay"? Sure. It's just up to you to use data to your advantage and get the best oil for your application and money.

ferb!