My old man told me to never trust a 'quick fix' additive for injector knock, and I should have listened

I had this 6.7 Powerstroke with a nasty knock that wouldn't go away. A guy at the parts counter swore by this 'Diesel Doctor' additive, said it would quiet it right down for $40 a bottle. My dad, who wrenched on semis for 30 years, always said those bottles are just expensive bandaids and to find the real problem. I bought the bottle anyway, poured it in, and the knock got softer for about 50 miles. Then it came back worse than ever. Turns out I had a failing injector cup, which the additive just masked for a bit. Ended up costing me over a grand to fix it right after I wasted time and money on the snake oil. Anyone else have a story about a 'miracle' fix that just made things worse?

2 comments

2 Comments

beth_butler757d ago

That's a tough lesson to learn, but your dad was spot on. Read a story in a truck forum about a guy with a Duramax using a similar product for a miss. It just gummed up the whole fuel system when the real issue was a tiny piece of trash in the line. Those additives can sometimes change the sound for a minute, but they never fix the broken part. It's like taking aspirin for a broken arm, you might not feel it but the bone is still snapped.

emma_hart7d ago

Exactly, it just masks the problem. I learned that the hard way with an old carburetor that needed a rebuild, not another bottle of miracle goop.