Q: Hi Greg, I have a Buick with 42,000 miles and GMC truck with 82,000 miles. I have recently gone to full synthetic oil for both vehicles in 5W-30 and 10W-30, respectively.
I use the truck in the summer in Michigan and then the Buick in the winter while in Arizona. Both vehicles are in storage about six months a year, and I drive each one about 5,000 miles in that time period. Should I change oil just before I store my collector vehicles or let them sit and then change when I use them for the new season? Also, do you use synthetics or regular oil in your cars? Your columns are very enjoyable. Thanks, Ron Krieger, Orleans, MI.
A: Thanks for your letter, Ron. If it were me, and since you don't let these vehicles sit for years at a time, I'd change the oil just before using them for the season. I've mentioned in previous columns that oil changes are to cars what showers and baths are to us humans. Some car owners can usually go an easy 5,000 miles between oil changes, others like to change every 3,000.
As for me, I'm one of the 3,000 to 3,500 mile drain interval fans, as fresh oil keeps everything clean inside. Today's engines are way more sophisticated than the antique or collector cars I write about, and engine oils have come a long way, too. Back in my day, there was no such thing as synthetic oil, but today the manufacturers are making better lubricants than ever and recommending them for regular use.
I do use synthetic oil in my cars mainly because of synthetic's superior cold weather starting abilities. Notable synthetics include Mobil 1, Lucas Oil, Quaker State, Valvoline, Amsoil, Pennzoil, Royal Purple and Castrol, to name but a few of the many excellent brands available.
In summary, when Corvette, Cadillac and Camaro/Trans-Am with the high performance LS-series engines came filled with Mobil 1 from the factory, it was an indicator of the superior qualities of synthetic oil.
However, with all this said, your car will also run well with regular crude based oils, as they are much cheaper and basically have the same drain intervals as the above mentioned synthetics (with the exception of Amsoil, which has extended oil life with filter changes of up to 12,000 miles.) I could write for a long time about the use of oils, but hopefully this answers your question.
Finally, to all of the collector car owners out there, it is OK to use synthetics on your older cars without a catalytic converter. Now, if your car has an oil leak, I'd stick with the conventional oil until it is fixed.
On the specialty side, Lucas Oil makes a special 10W40 Hot Rod & Classic Car Motor Oil with higher zinc content while Amsoil produces a synthetic for classic cars called Z-Rod. The choice is yours. The extra zinc content helps better protect the mechanical type camshafts that are used in muscle cars from the 1960s and earlier as opposed to today’s hydraulic roller cams that come in many engines.