Every 12 000 miles or 12 months
25.11 a Tools required for spark plug
removal, gap adjustment and refitting
of a weak mixture or too hot a plug (a hot plug
transfers heat away from the electrode slowly,
a cold plug transfers heat away quickly).
13 If the tip and insulator nose are covered
with hard black-looking deposits, then this is
indicative that the mixture is too rich. Should
the plug be black and oily, then it is likely that
the engine is fairly worn, as well as the mixture
being too rich.
14 If the insulator nose is covered with light
tan to greyish-brown deposits, then the
mixture is correct, and it is likely that the
engine is in good condition.
15 The electrode gap is of considerable
importance as, if it is too large or too small, the
size of the spark and its efficiency will be
seriously impaired. The gap should be set to
the value given in the Specifications.
25.16b Measuring the spark plug gap with
a wire gauge...
25.11b Removing a spark plug
16 To set the gap, measure it with a feeler
blade or wire gauge and then bend open, or
close, the outer plug electrode until the correct
gap is achieved (see illustrations). The centre
electrode should never be bent, as this will
crack the insulator and cause plug failure, if
nothing worse. If using feeler blades, the gap
is correct when the appropriate-size blade is a
firm sliding fit.
17 Special spark plug electrode gap adjusting
tools are available from most motor accessory
shops, or from some spark plug
18 Before fitting the spark plugs, check that
the threaded connector sleeves are tight, and
that the plug exterior surfaces and threads are
25.16c . . . and adjusting the gap using a
special adjusting tool
25.16a Measuring the spark plug gap with a
It is very often difficult to insert spark
plugs into their holes without cross-
threading them. To avoid this possibility,
fit a short length of 5/16-inch internal
diameter rubber hose over the end of
the spark plug. The flexible hose acts as
a universal joint to help align the plug
with the plug hole. Should the plug
begin to cross-thread, the hose will slip
on the spark plug, preventing thread
damage to the aluminium cylinder head.
Remove the rubber hose, and tighten
the plug to the specified torque using
the spark plug socket and a torque
wrench. Fit the remaining spark plugs in
the same manner.
Models with Direct Ignition
19 Refit the ignition cartridge using a reversal
of the removal procedure. Tighten the four
screws to the specified torque.
Models without Direct Ignition
20 Connect the HT leads in their correct
order, and refit the rubber grommet.
21 Refit the inspection cover, and tighten the
26.1 a Withdrawing the dipstick from the
front of the gearbox
26.1 b Upper and lower level marks on the
gearbox oil level dipstick
Note: A suitable Allen key will be required to
unscrew the manual transmission filler and
level plugs (as applicable). This can be
obtained from most motor factors, or from
your Saab dealer.