HOW TO: SEAFOAM (Motor Treatment) A 370z

Jordo!

Yeah... agreed. The "I see smoke coming out" is essentially a "I know it's working because it's tingling" rationale.

Where is the evidence it actually does anything to clean the valve train? Where is the independent data on improved gas mileage or whatever other claims it purports?

I wouldn't pour this gunk into the engine. I'd say its as likely to weaken seals or gunk EVAP valves as it is to remove any presumed carbon deposits.

That users report no apparent harm (other than a CEL!?!) is hardly a ringing endorsement. That the car "runs smoother" afterwards is shaky anecdotal evidence at best.

Anyone adhering to a regular maintenance schedule, using top tier fuel, and perhaps after 60 - 200K miles a proper fuel injector cleaning service (rather than just dumping extra detergents into the tank) is doing plenty to keep the engine in excellent running condition for several hundred thousand miles easily without adding this alchemist's brew.

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