What do all those numbers mean?

Those of us that are of the "gearhead" persuasion all have our little niches of expertise. One of the most argued subjects that seems to catch all gearheads is oil brand and weight.

Sometimes you might even see a heated battle over who has the best oil. Usual conversations might have phrases such as "my dad always used (insert your choice here) brand, so I use it too."

"Well, if it was good enough for him, then it's better than what you use!" Then you might see fists fly.

Now that we have evolved into the 21st century, it's my belief that we should be less concerned with brand and more concerned with quality and flow characteristics. Aircraft mechanics and hot-rodders still like the thick stuff. Philosophies of yesteryear included "the thicker the better" and "if it burns it or leaks it, thicken it up." Following these schools of science is better left in the archives. Today's engines require a completely different lubricant strategy. The truth is, "the thinner the better."

In the early 1990s, we had a small, go-cart-sized Formula One racer that was sponsored by Valvoline. We raced this car in non-sanctioned events from time to time. The cars in these events were identically matched in weight, tires and engines. We soon found that driver weight was a key factor, so we always put the smallest driver behind the wheel. One year, the Salem Boys team won all the time. We were continually being challenged by the officials for possibly not playing by the rules. The reason for our success, you ask? The other teams were using 30-weight oil. We used 0W-20 compressor oil. We ran circles around the competition. It only makes sense: thin oil flows faster!

What do the numbers mean? Example: 0W-20. This means that the oil flows like a 0 weight when cold and a 20 weight when warm. So what about the "W?" It stands for winter. Most cars run great on 10W30. A lot of new cars and most imports recommend 5W30 or 5W20 oils. Some Hondas now use 0W20. Tighter tolerances and thinner oils mean better flow and better lubrication.

As always, I recommend following your owner's manual for type of engine oil and change intervals.

Send me questions about your car, truck or favorite city issue.

John Salem will answer online posts to this column at kdminer.com or write to him at gearbox@npgcable.com. This column is dedicated to help the motoring public solve their automotive problems. Salem is an L1 rated, ASE-certified master automobile technician and has owned and operated Salem & Sons Auto in Kingman for more than 17 years.