Tom

Tom,

Q Is fuel system cleaning really necessary? If so, at what mileage? Or is it a

“fluffy“ extra that the dealership wants to talk me into, like rust proofing.

Joe—Montana

Joe,

A Fuel system cleaning is a part of your maintenance schedule every

30,000 miles or so (mileage intervals from vary carmaker to carmaker). This
is a necessary service to clean out the varnish and dirt buildup that takes
place in the fuel delivery system. Fuel injectors are sprayers that have tiny
orifices. When these small openings get clogged from dirt and varnish
buildup, they dribble fuel instead of delivering a steady properly mixed dose
of air and fuel, necessary for efficient combustion. Clogged injectors result in
higher tailpipe emissions, poorer fuel economy, and poor engine performance
overall.

Intake plenums, cylinder heads, valves, and pistons also get dirty over
time from unburned fuel settling on them. This hardened, unburned fuel saps
the fuel out of the air-fuel mixture, resulting in a lean condition. The car’s
computer “sees“ this lean condition and richens fuel mixture, resulting in
decreased fuel mileage. Fuel system cleaning should be performed every
35,000 to 45,000 miles. As for rust protection, depending on where you live
and if salt is used during the winter, a good rust protection will protect your
investment, so don’t under value it.