One maintainer for two pickup truck batteries

Dear Doctor: I purchased a 2016 Ram 3500 heavy-duty pickup truck with the Cummins diesel engine. This truck has two 12-volt batteries. I believe in using battery maintainers for my vehicles. Can I use two maintenance chargers at the same time, or should I alternate between the two batteries?

— Jim

Dear Jim: I have two batteries in my Chevy pickup truck and they are connected in parallel. When I use the maintenance charger I connect the positive to either battery and the ground connection to the engine block. There is no need for two maintainers.

Dear Doctor: I own a 2004 Mercedes-Benz CLK500 with 62,000 miles, which runs great and I love it. I’ve been noticing an oil leak over the last few months on my garage floor. My mechanic uses a tech support service who advised him to change out the rubber hoses and use compressed air to blow out any oil that seems clogged. I was told that since the car has low mileage and a large engine, that perhaps things such as the seals have dried out. Can you help?

— Jeff

Dear Jeff: Your Mercedes’ V-8 is a complex engine with a lot of plastic and rubber vent hoses, as well as rubber hose connectors. The underhood temperatures run high — and plastic and rubber do break down over the years. I suggest cleaning off the oil at a detail shop. Then find a shop that can add dye to the engine and use a black light to find the source of the leaking.

Junior Damato is an ASE-certified Master Technician. E-mail questions for publication to Mail questions to Motor Matters, P.O. Box 3305, Wilmington, DE 19804.