I finally tried that diesel fuel additive my buddy swore by for years

I mean, I always thought it was just snake oil for old guys who liked to spend money. But last winter, my '06 Duramax was getting real sluggish on cold starts, like 15 seconds of cranking. He gave me a bottle of his stuff and said to run it for two tanks. Idk, maybe it's just me but after the second fill-up, it fired right up even on a 20-degree morning. Has anyone else had a specific additive actually fix a real problem like that?

3 comments

3 Comments

wendy1311mo ago

Honestly, that sounds like pure luck to me. Cold weather is weird, and engines can act different day to day. You probably just had a couple good starts after a run of bad ones. I've never seen a bottle of anything actually fix a real mechanical issue. If something's wrong, it needs a real part, not a magic potion.

phoenixw111mo ago

My engine runs on hope and denial.

betty_wells1mo ago

Respectfully disagree on the fuel additive part. I've used diesel treatments for years to stop gelling in winter. It's not magic, it's just chemistry that changes how the fuel behaves in the cold. Some of those bottles absolutely fix specific issues like water in the tank or sticky injectors. You're right that a broken part needs replacing, but additives are meant for maintenance, not major repairs.