Western-Star

Wheels: An e-mail from Bob in Pennsylvania says, "I just read your great article on engine oils. I'll be aware when I purchase oil and change it for my 2001 Corvette that I bought last year. As a retired aircraft technician (piston type), I am curious if the only concern is the used extended mileage oil. Would the use of extended service synthetic engine oil be acceptable in an older vehicle? I think it would be acceptable. I would value your opinion very much on the use of this oil. Do rubber seals play a role in this? Thanks for your assistance."

Halderman: Extended service and high mileage oils are not the same. Extended service oils have more anti-acid and other additives so that it will protect the engine for a longer time. Many extended oil change oil companies advertise that you can go up to 15,000 miles without changing the oil. This is not the recommended interval. These oils will not hurt the catalytic converter. All of the oil today is formulated with reduced zinc and other additives that could hurt the converter if oil is burned and then travels through the exhaust system. High-mileage oils are different from extended oil change oils. These contain extra seal swelling chemicals, usually esters. If you look closely most of these oils (extended change and high-mileage) do not meet the factory standards. What would I do? I recommend using any oil you wish that has the ILSAC "star burst" label on the front of the container and change the oil regularly (at least every six months). Always check to see if the oil meets the specifications for your vehicle. For example, most Mercedes' vehicles require very specific viscosity oil that may not have the star burst symbol on the label.

Wheels: From Jake via e-mail, "I have a Dodge Caravan that I put ten dollars of gas in the tank and my fuel gauge needle floats to empty, and the engine dies. Can you tell me what is happening?"

Halderman: Let me try to understand your concern. I assume that when you put gas in the tank that the fuel gauge dropped to empty and the engine stalled. Right? The fuel gauge and the fuel pump are both inside the fuel tank. An electrical connector could be corroded and this could stop the fuel pump from working and also the fuel gauge. Check that all of the electrical connections at the fuel tank and nearby wiring are OK. If so, then a professional should look at it to determine the cause as it could be something simple, but it could also be due to bad fuel pump/fuel gauge assembly, which is not cheap.

James D. Halderman is an ASE-certified master technician, a member of the Society of Automotive Engineers and the author of 12 textbooks. Submit your automotive care questions to Halderman via e-mail at jhalderman2@juno.com, or write him in care of: Wheels, Marketing Publications Department, Dayton Daily News, 1611 S. Main St., Dayton OH 45409.