You don’t want anything combustible going into the engine. If the glow plugs ignite whatever you spray in, it’ll bend the pushrods best case scenario. I don’t think wd-40 is even combustible :confused: so why would we spray that in.
Why they going bad. We have an 05 at the house with a factory battery and an optima yellow top (back when they were good) not sure how they both lasted so long :spit: