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Engine Carbon Cleaner: The Test Results

A head-to-head test of 1 engine carbon cleaner options with the measured results for each. See how they ranked and watch the full test video.

The verdict
Ranked first

Antifreeze 50% water / ethylene glycol mix

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The measured results

Every number below is read straight from the test. Scroll sideways to see all measurements. Products are listed in the order they finished.

ProductSpray mist testDrip method testCompression testOil contamination check
1Antifreeze 50% water / ethylene glycol mixdid the spray mist actually help? I think it did. There's quite a bit of cleaning through the center part of the piston as well as around the intake valvewell, I'm really surprised at how well that worked. I did not expect the drip to work so much better than the spray mistCompression test 105 PSI ... Compression test: 105 PSI (no change)I don't see any visible contamination. In other words, it's not a milky white color

How it was tested

  • spray mist carbon cleaning test on a running, fully warmed engine
  • drip method carbon cleaning test through the carburetor
  • compression test before and after treatment
  • visual oil contamination check

Well, I'm really surprised at how well that worked. I did not expect the drip to work so much better than the spray mist.

From the test video verdict.

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