duncanm

I've read various different opinions on the forum archives. According to the Bentley (and from what I've read in general) 5w30 is the best weight to run in the winter. I have however read some people saying that 5w30 is too thin for the 7A.

Thoughts?

dtompsett

I run 20w50 in the summer... I consider anything thinner perfect for winter.

Honestly forget what I run... I think 10w40... never been a problem starting. Give it a minute to warm up.

duncanm

If the Bentley is correct, I should go for a 5w30 until the spring. We do get the occasional -20 in the winter...

dtompsett

if they seem higher than normal, switch to 10w30 or 10w40

red90q

I agree with Doug. I use 10w30 in the winter. 5w30 is too thin for me.

nbvolks

So far the motor seems fine with it.

rggpa2

5w-30 and 10w-30 oils are both 30 weight oils (as defined by and subject to API testing) at standard operating temperatures. The 5w and 10w are relative terms (the "w" has nothing to do with "weight") associated with the low temperature flow characteristics of a multi-vis oil. Therefore, a 5w-30 is not, by default, thinner than a 10w-30 oil. But it does flow better at low temperatures. Both 5w-30 and 10w-30 oils are (at low temperature) actually "thicker" than a single grade 30 weight oil is at its designed operating temperature!

To muddy the picture a bit, different blends/brands of multi-vis 30 weight oils can be thinner or thicker than others. The 30 weight designation is actually a range (defined by API) of viscosities. So a 30 weight oil at the low end of the defining viscosity range would be thinner than a 30 weight at the high end of the range. Also, the viscosity index improvers (long chain polymers) used as an additive in these multi-vis oils tend to break down (shear) over time, causing the oil to thin in use. Different brands or even different blends within the same brand react differently wrt shearing.

These factors (as well as many others) lead to any number of perfectly valid user preferences for specific multi-vis oils in their specific cars/engines. Find a good quality oil that works for you and use it! Or else you can read volumes of oil specs and drive yourself nuts!

Soap box put away!

JPCady

good info...good to know!

duncanm

wow...thank you.

duncanm

after the 5w30 change today

But, even after a 30 minute drive, the gauge doesn't read above 70 degrees.