terry_barnes•6d agoProlific Poster

That time I chased a vacuum leak for 3 hours and it was a 50 cent grommet

Was working on a 2012 Ford Focus in my buddy's shop over in Akron last Tuesday. Customer brought it in claiming a rough idle and a check engine light for a lean code. I spent a solid 3 hours checking every vacuum line, spraying carb cleaner, even pulled the intake manifold off twice. Finally took a break and grabbed a coffee, kid working next to me pointed at a cracked rubber grommet on the brake booster line. Ten minutes later I had it swapped, idle smoothed out perfect, and the light went off. Now I'm wondering if I should always start with the cheap obvious stuff first or if deep diving is the only way to be thorough. What do you guys do when you've got a stubborn vacuum leak?

2 comments

2 Comments

michael_bennett116d ago

Small thing, but a 2012 Focus doesn't actually use a brake booster vacuum line from the intake, it has a vacuum pump on the back of the engine for the brakes. That cracked grommet you found was probably on the PCV or purge valve line going into the intake manifold somewhere. Still, yeah, three hours chasing a fifty cent part hurts. I usually grab a cheap smoke machine first, it finds those little cracks in about five minutes flat. Saves me from pulling my hair out and looking dumb while a kid drinks coffee and points at the obvious.

gavinp445d ago

Right, because nothing says "I'm a professional" like a fresh-faced kid with a coffee pointing at the one thing you missed for three hours. Saved my bacon, but man did I have to eat a slice of humble pie. I'm with you on the smoke machine, that thing would have called me out in two minutes flat instead of letting me look like a goofball dismantling half the engine bay. Guess deep diving is just the mechanic's version of checking the fridge five times for the milk that's right on the counter. Lucky for me, that kid's getting a free lunch next time I see him.

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