C5/C6 Corvette Oil Change - Corvetteconomics 101

A C5/C6 Oil Change The Right Way

From the May, 2010 issue of Corvette Fever

By Tom Benford

Photography by Tom Benford

I'm feeling the economic pinch big-time these days (like just about everyone else I know) and I am tightening my belt, trying to make every dollar stretch as far as possible. In addition to cutting back on frivolous, whimsical, and non-essential spending, I'm also doing a lot of things around the house and garage myself rather than farming them out, and you can, too. One of the ways to save yourself some significant bucks is to do routine maintenance chores on your Corvette yourself, like flushing the cooling system, rotating the tires (if applicable) and changing your own oil.

At first blush, changing the oil in a C5 or C6 sounds like a no-brainer, right? And yet, it is surprising how many people don't do it correctly, and only wind up with a partial oil change when doing it themselves. The reasons for this are 1) on C5s, the oil drain plug is located at the front of the oil pan rather than at the rear, and on C6s it's next to the oil filter, so jacking up the front of the car prevents all of the oil from draining and 2) the "bat wing" configuration of the C5 oil pan itself traps and holds oil, so it takes a considerable amount of time (about 10-15 minutes) for all the oil to drain completely; most folks don't give adequate drain time, so up to a quart of old oil can remain in the engine.

There are several reasons to change your own oil, such as: You can use the brand of oil and filter you prefer, rather than being forced to use what the dealership or service shop is pushing that day.

You can shop around for the best price on the oil and filter at different auto parts stores and/or Walmart, K-Mart, Price Club, etc. to get the best value for your dollar. And, if you purchase the 5- or 10-quart containers rather than individual quart bottles, you can save even more money.

You're the one doing the work, so you're in charge of quality control all the way through; many shops and dealerships don't let the customers in the service area, so you can't see what's being done;

You can take your time, which is important for draining as much of the old oil out of your engine as possible; I let my C5 drain for a full 15 minutes before replacing the drain plug, filter, and refilling. Time is money to dealerships and shops, so the faster they can get you and your car in and out, the more profitable each customer becomes. Rest assured, they won't let your C5/C6 drain for a quarter of an hour or more!

There's a lot of satisfaction in doing your own work, and most people who do so find that they enjoy their Corvettes even more; it's almost a Zen thing wherein you "become one with the machine."

So there you go. And as far as equipment goes, doing a few oil changes and other routine maintenance can quickly amortize the cost of a good hydraulic trolley jack, two pair of jackstands, and any other miscellaneous tools or equipment you may acquire along the way. I always consider tools and equipment as investments that pay me dividends each and every time I use them.

One other thing I should mention here is oil capacity; be sure to consult your C5 or C6 owner's manual for engine oil capacity. I use six quarts in my '98 C5, and this brings the dipstick level up to the mid-point on the hash marks, even though the manual says 5.5 quarts (in reality, it's 6.5 quarts); remember that the filter will hold about a half-quart, so I believe that accounts for the extra oil.

A question I've been asked frequently over the years is, "How often should I change the oil in my C5/C6?" There are many ways to answer this question, but I suspect that no single answer will satiate everyone. Many folks go with the traditional "change the oil and filter every 3,000 miles whether it needs it or not" philosophy, while other folks wait for the DIC (Driver Information Center) to tell them it's time for an oil change. If you abide by what the DIC tells you, it's a good idea to change the oil and filter between 25 and 10 percent, rather than letting it go to 5 percent or less oil life remaining. The reason for this is that GM's algorithm for the DIC to determine how fast the oil life reading changes from 100 to 0 percent, but, while pretty sophisticated, doesn't account for dust and other contaminants that may steal additional lubricity from the oil. So, to be on the safe side, don't push the oil life envelope. Several manufacturers of synthetic oils make claims (some hard to believe) that you can go 5,000, 10,000, 20,000 miles, or even more before changing the oil. Well, not my C5. I change my oil and filter at 5,000 miles. Regardless of what brand of oil you use, never let your oil go past 10,000 miles before changing it or you're really asking for trouble.