The battery terminal trick that got my diesel firing in 20 degree weather

Cold snap hit Denver last Tuesday and my 7.3 diesel would not turn over. I had fresh batteries but still got that slow crank. Tried starter fluid, glow plugs, all the usual stuff. Then an old fleet mechanic at the shop next door told me to clean the ground cable connection at the frame rail with a wire brush and dielectric grease. Did that and it fired right up after 3 tries. Anyone else had a bad ground that acted like a dead battery?

2 comments

2 Comments

the_miles3d ago

Honestly I gotta push back on the "bad ground" theory here. You said the batteries were fresh and you still got a slow crank, that points way more at a weak starter or maybe even bad cable ends themselves, not some random frame rail spot. I've seen guys chase grounds for hours when the real issue was the starter solenoid getting lazy in the cold, and dielectric grease can actually make things worse if you don't apply it right, it can trap dirt and moisture if the surface isn't perfectly clean. Plus if the ground was truly that bad, you'd probably see weird electrical stuff like dim lights or a flickering dash, not just a hard start. Glad it worked for you but I'm betting it was the wire brushing that fixed the connection, not the grease, and that same trick would've worked on the starter post just as easy.

willowr963d ago

Most starter draw is like 150 amps and volts drop at the cable ends, so that wire brushing on the frame rail was the real fix, @the_miles.