Page 63 - Energize October 2022

TECHNICAL

Dipstick disasters and loss control

Say ‘dipstick’ and any driver’s mind flies towards an engine oil dipstick – especially older truck

models that are not electronically equipped with sump level sensors and instrument panel signals.
But modern trucks come standard with other fluid dipsticks as well, and that is where it all begins.

by Dave Scott, independent author; information supplied by WearCheck

driver’s daily check sheet will include engine oil levels. Dipstick procedures must be cold checks
But, unless the check is specific and limited to the engine Top-up oils are most often stored at the fuel pump, which entails
A only with training on how and when to read the dipstick, a vehicle movement to the fuel pump before checking the
there is a danger that an ‘enthusiastic’ driver starts checking dipstick – oil levels should be checked before engine start-up.
all the other dipstick levels that are best left to workshop By the time the vehicle arrives for refuelling, the engine has
technicians. warmed up and oil is in the cylinder head and other galleys to
Power steering, torque convertor automatic transmissions give a false dipstick reading. A hot truck engine cylinder head can
and automated manual transmission (AMT) viscous couplings hold many litres of lubricant when switched off – in some cases
all require top-up techniques at operating temperatures with the recommended waiting period prior to checking the engine
absolute cleanliness. Also, some systems – such as automatic sump dipstick is at least 10 to 30 minutes, depending on engine
gearboxes – require the lubricant level to be checked while the design and sump capacity.
engine is running at idle. And then all components outside of the
engine require very specific lubricants totally different to engine Case study: The dipstick that was too short
lube specs. A new truck recorded excessive oil consumption. Before the
engine was going to be stripped down, a visiting service manager
Early morning start-up audit asked for a spare dipstick from the parts division for comparison
Start-up and checking procedures are often executed in poor to the dipstick already in the engine that was used as the
lighting conditions and pre-dawn, without a torch. This makes measuring device for excessive oil consumption. The wrong
reading an engine dipstick a hit-and-miss procedure, where dipstick was present in the motor and, being too short, the
the faulty perception exists that it is better to err on the side engine was overfilled every time while blowing out the excess oil
of overfilling. The hit-and-miss problem is compounded with on every trip – the correct dipstick solved the problem without a
returning and inserting the dipstick in the dark and missing the costly, and fruitless, engine teardown.
dipstick seating orifice – the bottom of the dipstick gets jammed
into grinding material collected around the dipstick entry point. The overlooked engine breather’s role
The accumulated contamination is then inserted into the A rotating crankshaft, churning the lubricant in the sump,
engine to initiate engine wear and premature failure – a disaster! creates a heavy oil mist that leaves through a breather that, on
modern engines, exits into the airflow before the turbocharger.
It sounds too basic to be true, but engine lube levels must be If it entered after the turbocharger, the turbo would pressurise
checked when a vehicle is on a level surface. the sump! Abnormal lubricant volume in the turbo will deposit

Figure 1: Dipstick and filler neck Figure 2: Engine oil dipstick under driver side from wheel arch

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