stevenqrdh@gmail.com wrote in news:1151097772.803097.296190@u72g2000cwu.googlegr oups.com:

> 2001 Civic LX - Supposed to use 5W-20 (I think that's what it says on
> the cap). I used 10W-40. It's what a mechanic recommended.


You can use 5W-30 instead of 5W-20, but don't use 10W-40.
Your mechanic is wrong. The heavier 10-weight will take
slightly longer for the oil pump to pull up.


>
> Not the 1st time I've used a diff oil than spec. Just wondering if
> there can be bad consequences if I use the wrong motor oil?



Not much, really. Perhaps a bit more bearing and cam/lifter wear
from cold.

At the moment, I'm actually considering a 0W-40 synthetic for my car.
After 270,000 miles, its oil consumption (2K/qt) is a bit high for
my tastes.



>
> Also, what exactly do those numbers and letters stand for? I think it
> refers to viscosity but I don't remember which number?
>


Google is your friend.
<http://www.google.com/search?hl=en&q=%22motor+oil%22+viscosity+numbers&b tnG=Google+Search>
From that search:
http://en.wikipedia.org/wiki/Motor_oil

A quick primer:
The "10W" means it pours like a straight 10-weight would when it's cold.
The "40" means it pours like a straight 40-weight would when hot.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/