Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement page 298

ENGINE <4G9> –
Good
High-pressure chamber
On-vehicle Service
NOTE
(1) If the vehicle is parked on a slope for a long period
of time, the amount of oil inside the lash adjuster will
decrease, and air may get into the high pressure
chamber when starting the engine.
(2) After parking the vehicle for long periods, the oil drains
out of the oil passage, and it takes time for the oil
to be supplied to the lash adjuster, so air can get
into the high pressure chamber.
(3) If either of the above situations occur, the abnormal
noise can be eliminated by bleeding the air from inside
the lash adjusters.
1. Check the engine oil and replenish or replace the oil if
necessary.
NOTE
(1) If there is a only small amount of oil, air will be drawn
in through the oil screen and will get into the oil
passage.
(2) If the amount of oil is greater than normal, then the
oil will being mixed by the crankshaft and a large
amount of air may get mixed into the oil.
(3) If the oil is degenerated, air and oil will not separate
easily in oil, and the amount of air mixed into the
oil will increase.
(4) If the air which has been mixed in with the oil due
to any of the above reasons gets into the high pressure
chamber of the lash adjuster, the air inside the high
pressure chamber will be compressed when the valve
is open and the lash adjuster will over-compress,
resulting in abnormal noise when the valve closes.
This is the same effect as if the valve clearance is
adjusted to be too large by mistake. If the air inside
the lash adjusters is then released, the operation of
the lash adjusters will return to normal.
11A-15