Dodge ram truck 3500 1996 Service Manual page 1000

I - 1 1 ENGINE
BR
D I A G N O S I S
AND TESTING (Continued)
NOTE: Worn valve guides or cocked springs are
sometimes mistaken for noisy tappets. If such is
the case, noise may be dampened by applying side
thrust on the valve spring. If noise is not apprecia­
bly reduced, it can be assumed the noise is in the
tappet. Inspect the rocker arm push rod sockets
and push rod ends for wear.
(3) Valve tappet noise ranges from light noise to a
heavy click. A light noise is usually caused by exces­
sive leak-down around the unit plunger, or by the
plunger partially sticking in the tappet body cylinder.
The tappet should be replaced. A heavy click is
caused by a tappet check valve not seating, or by for­
eign particles wedged between the plunger and the
tappet body. This will cause the plunger to stick in
the down position. This heavy click will be accompa­
nied by excessive clearance between the valve stem
and rocker arm as valve closes. In either case, tappet
assembly should be removed for inspection and clean­
ing.
(4) The valve train generates a noise very much
like a light tappet noise during normal operation.
Care must be taken to ensure that tappets are mak­
ing the noise. If more than one tappet seems to be
noisy, it's probably not the tappets.
ENGINE OIL P R E S S U R E
(1) Remove oil pressure sending unit.
(2) Install Oil Pressure Line and Gauge Tool
C-3292. Start engine and record pressure. Refer to
Oil Pressure in Engine Specifications for the proper
pressures.