So, I have a 2000 Chevrolet Malibu. I've been fighting with an EVAP leak (code PO442, a small leak) for a few months now. When I originally had it smoke-tested at the mechanic, they told me that it was my fuel filler neck, that it was very rusted and porous. I eventually replaced it with my uncle's help. The problem is that, two weeks later, the check engine light came back on, with the same code. I've gotten a new gas cap, replaced an old rotted hose, but I just can't seem to stop the leak, and I don't really have the funds to pay for another smoke test.

My question is, are there safe DIY ways to test for an EVAP leak? I've heard that using carb and choke cleaner sprayed over the hoses and such would cause the engine to rev if it's sprayed over the point of the leak. I've also heard that you can do a bubble test similar to what is done with leaking tires if you pressurize the lines. But honestly, I don't know what will work and what won't, so if anyone has any experience/ideas and can help me out, I would really appreciate it.

  • 2
    Smoke machine is the only good way to test an evap system. – Moab Aug 1 '19 at 13:36
  • I know that the smoke is the best way to test it. I'm looking to see if there are other options, such as the ones I listed. – Jay Kay Aug 1 '19 at 16:47
  • I love this video. Cheap smoke tester. – zipzit Aug 1 '19 at 19:01
  • Hmm, i've considered using this method. But I've heard that this method might not be safe for evap leak testing, since your technically pumping hot smoke into your car that could potentially ignite the fuel vapors. Any advice in that regard? – Jay Kay Aug 2 '19 at 3:08

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