Dodge ram truck 3500 1996 Service Manual page 999

BR ^ — — — — — ENGINE 9 - 9
DIAGNOSIS AND TESTING (Continued)
pected source. Adjust the regulator to the suitable
test pressure that provide the best bubbles which
will pinpoint the leak source. I f the oil leak is
detected and identified, repair per service manual
procedures.
(10) I f the leakage occurs at the rear oil seal area,
refer to the section, Inspection for Rear Seal Area
Leak.
(11) I f no leaks are detected, turn off the air sup­
ply and remove, the air hose and all plugs and caps.
Install the PCV valve and breather cap hose. Proceed
to next step.
(12) Clean the oil off the suspect oil leak area
using a suitable solvent. Drive the vehicle at various
speeds approximately 24 km (15 miles). Inspect the
engine for signs of an oil leak by using a black light.
INSPECTION FOR REAR SEAL AREA LEAKS
Since i t is sometimes difficult to determine the
source of an oil leak in the rear seal area of the
engine, a more Involved inspection is necessary. The
following steps should be followed to help pinpoint
the source of the leak.
I f the leakage occurs at the crankshaft rear oil seal
area:
(1) Disconnect the battery.
(2) Raise the vehicle.
(3) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of oil.
Use a black light to check for the oil leak:
(a) Circular spray pattern generally Indicates
seal leakage or crankshaft damage.
(b) Where leakage tends to run straight down,
possible causes are a porous block, distributor seal,
camshaft bore cup plugs, oil galley pipe plugs, oil
filter runoff, and main bearing cap to cylinder
block mating surfaces. See Group 9, Engines, for
proper repair procedures of these Items.
(4) I f no leaks are detected, pressurized the crank­
case as outlined in the section, Inspection (Engine oil
Leaks In general)
CAUTION: Do not exceed 20.6 kPa (3 psi).
(5) I f the leak is not detected, very slowly turn the
crankshaft and watch for leakage. I f a leak Is
detected between the crankshaft and seal while
slowly turning the crankshaft, i t is possible the
crankshaft seal surface Is damaged. The seal area on
the crankshaft could have minor nicks or scratches
that can be polished out with emery cloth.
CAUTION: Use extreme caution when crankshaft
polishing is necessary to remove minor nicks or
scratches. The crankshaft seal flange Is specially
machined to complement the function of the rear oil
seal.
(6) For bubbles that remain steady with shaft
rotation, no further Inspection can be done until dis­
assembled. Refer to the service Diagnosis—Mechani­
cal, under the Oil Leak row, for components
Inspections on possible causes and corrections.
(7) After the oil leak root cause and appropriate
corrective action have been identified, Refer to Group
9, Engines—Crankshaft Rear Oil Seals, for proper
replacement procedures.
HYDRAULIC TAPPETS
Before disassembling any part of the engine to cor­
rect tappet noise, check the oil pressure. I f vehicle
has no oil pressure gauge, Install a reliable gauge at
the pressure sending-unit. The pressure should be
between 207-552 kPa (30-80 psi) at 3,000 RPM.
Check the oil level after the engine reaches normal
operating temperature. Allow 5 minutes to stabilize
oil level, check dipstick. The oil level in the pan
should never be above the FULL mark or below the
ADD OIL mark on dipstick. Either of these two con­
ditions could be responsible for noisy tappets.
OIL LEVEL
HIGH
If oil level is above the FULL mark, i t is possible
for the connecting rods to dip Into the oil. With the
engine running, this condition could create foam i n
the oil pan. Foam in oil pan would be fed to the
hydraulic tappets by the oil pump causing them to
lose length and allow valves to seat noisily.
LOW '
Low oil level may allow oil pump to take in air.
When air is fed to the tappets, they lose length,
which allows valves to seat noisily. Any leaks on
Intake side of oil pump through which air can be
drawn will create the same tappet action. Check the
lubrication system from the intake strainer to the
pump cover, including the relief valve retainer cap.
When tappet noise is due to aeration, i t may be
intermittent or constant, and usually more than one
tappet will be noisy. When oil level and leaks have
been corrected, operate the engine at fast idle. Run
engine for a sufficient time to allow all of the air
Inside the tappets to be bled out.
T A P P E T NOISE DIAGNOSIS
(1) To determine source of tappet noise, operate
engine at idle with cylinder head covers removed.
(2) Feel each valve spring or rocker arm to detect
noisy tappet. The noisy tappet will cause the affected
spring and/or rocker arm to vibrate or feel rough in
operation.