Video summary

Can $59 in Amazon Parts Save My 450,000 Mile Prius?!

Main summary

Key takeaways

Product Review

Product reviewed / used

A low-cost Amazon/aftermarket “tune-up kit” for a 2010 Toyota Prius (1.8L): 4 spark plugs + 4 coil packs (branded as a kit by Mars Ram / generic Chinese listing). The price mentioned is $56.

Key results and features mentioned

  • What’s included: Four new ignition coils and four new spark plugs (described as “double iridium/double platinum”-type phrasing in the subtitles).
  • Primary DIY task: Replacing spark plugs and coils on the Prius.
  • Observed condition before work (context):
    • Coolant/water in the oil (“milkshake” froth). BlueDevil was used temporarily to help seal a coolant leak.
    • A misfire on cylinder #1 was suspected to be related to possible head gasket issues, given the combination of frothy oil + low coolant + misfire symptoms.

User experience (DIY difficulty)

The speaker emphasized that the job looks simple but is not on this Prius generation due to tight space and parts in the way.

Main pain points

  • Limited access to coil boots/plugs; the coils are large metal bodies with small rubber boots, requiring careful maneuvering.
  • Significant disassembly is required to reach the plug area:
    • Remove wiper arms (three 14mm bolts).
    • Remove windshield wiper transmission/cowl components and many 10mm bolts/clips.
  • Toyota-style packaging annoyances:
    • The speaker notes clips appeared missing on the car.
  • They completed the work with the battery still connected (which they admit is not recommended).
  • Spark plug #1 issue:
    • Plug #1 “was not tight” and was apparently barely seated/loose from the start, which likely contributed to compression leakage under load.

Time spent

  • Roughly ~45 minutes total (started around 4:50, entered maintenance mode/first start around 5:22–5:30).

Performance / outcomes after installation

Running condition

  • The engine started and ran smoothly at idle (“purr like a kitten”).
  • Frothy oil was reportedly gone when checked after the drive (they still planned an oil change).

Fuel economy improvement (major selling point)

  • Previous highway fuel economy: ~32.8 mpg
  • After the tune-up: ~40.3 mpg average over a ride (about 21.4 miles noted)
  • Briefly mentioned: possibly reaching ~41 mpg during the trip
  • Reported even with the check engine light on: ~40 mpg

Check engine light

  • After driving, the CEL came on solid (not flashing).

Pros (as stated/shown)

  • Cost-effective: $56 for coils + plugs.
  • Restored fuel economy: from about low-30 mpg back to ~40 mpg, consistent with what they expected from a high-mile Prius.
  • Fix for loose plugs/coils: they discovered two spark plugs were not tight (especially cylinder #1), which likely contributed to misfire behavior under load.
  • Temporary coolant-in-oil mitigation: after using BlueDevil earlier, the speaker reports no more froth afterward (not directly part of the $56 kit).

Cons / limitations

  • Does not fully fix the root issue: diagnostics still show:
    • Cylinder 1 misfire (pending/intermittent)
    • Catalyst system efficiency below threshold (bank 1 pending)
    • TPMS code
  • The misfire is described as intermittent/random, complicating troubleshooting.
  • The video suggests unresolved concern that catalyst efficiency issues may be secondary to misfires (unburnt fuel) or related to exhaust/emissions problems such as a partially plugged catalytic converter or EGR-related concerns, but the cause is unclear.
  • The car reportedly has an unusually complex emissions setup, potentially involving multiple catalytic converters (possibly four).

Comparisons made

  • No direct comparisons to other brands/kits were provided.
  • The narrative implies a comparison between:
    • a cheap tune-up parts approach vs.
    • the expectation of a much bigger repair.
  • They also compare actual performance to expected Prius norms:
    • Expected ~40+ mpg highway vs. prior ~32 mpg

Unique points mentioned (all)

  1. A 2010 Prius with 448,000 miles, purchased cheaply at auction (final $3,300 out the door).
  2. Pre-existing problems included coolant leak into oil (“milkshake” oil), temporarily addressed with BlueDevil.
  3. Cylinder #1 misfire suspected; possible head gasket concern after symptoms.
  4. Spark plug/coil replacement is harder than it looks due to Prius packaging/access.
  5. Aftermarket kit on Amazon costs $56 and includes 4 plugs + 4 coils.
  6. Wiper/cowl removal uses many 14mm and 10mm fasteners; clips/wiring harness removal is involved.
  7. Speaker notes missing/incorrect clips and references a bolt/fastener issue (stripped/long bolt note).
  8. Coil boots/plugs are difficult to maneuver in tight space.
  9. Discovery: spark plugs (cyl #1 and #3) were loose/not tight, with cylinder #1 essentially causing poor seating/compression leakage.
  10. After install, the car runs smoothly at idle.
  11. After install and drive, they claim no froth on the oil cap.
  12. Fuel economy jumped from ~32.8 mpg to ~40.3 mpg average over the ride.
  13. Check Engine Light returned as solid.
  14. OBD results: - Cylinder 1 misfire (pending/intermittent) - Catalyst system efficiency below threshold (bank 1 pending) - TPMS code
  15. Troubleshooting possibilities discussed include: - clogged injector, valve adjustment, low compression, catalyst/converter issues, EGR system issues, wiring/harness/ECM/PCV, etc.
  16. Misfire appears under heavy load: - freeze-frame shows calculated load ~87% when misfire began.
  17. They speculate misfire could contribute to catalyst efficiency problems via unburnt fuel, but they don’t know the true cause-and-effect (“chicken/egg”).
  18. They plan further work and mention getting a new code reader since the freeze frame was temporarily missing.

Verdict / recommendation (based on the video)

  • Recommendation: Worth doing as a low-cost, high-impact maintenance step—the $56 plug/coil kit significantly restored highway fuel economy (~32 → ~40 mpg) and corrected at least part of the running problem (especially loose plugs).
  • But: It does not fully resolve the intermittent cylinder #1 misfire and catalyst efficiency code(s). Expect further diagnostics beyond plugs/coils (potentially including injector/compression/valves or exhaust/emissions components).

Speakers/views

  • Only one primary speaker appears in the subtitles (the mechanic/host “Randy” is mentioned but not presented as a separate expert viewpoint with distinct conclusions).
  • No additional separate expert perspectives are provided beyond the host’s narration.

Original video