Jon - 3 and 4 are compatible formulas, 4 has a higher temperature tolerance - avoid dot 5, silicone

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature we find it attached to the rest of the world" John Muir
"When we tug a single thing on an old truck, we find it falls off" me
Some TF series details & TF heater pics & Rust-a-holics Unanimous parking lot