2004 ISUZU TF SERIES low oil pressure

ENGINE MECHANICAL (6VE1 3.5L) 6A-11
Symptom Possible Cause Action
Engine overheating Level of Engine Coolant too low Replenish
Fan clutch defective Replace
Thermostat defective Replace
Engine Coolant pump defective Correct or replace
Radiator clogged Clean or replace
Radiator filler cap defective Replace
Level of oil in engine crankcase too
low or wrong engine oil Change or replenish
Resistance in exhaust system
increased Clean exhaust system or replace
defective parts
Throttle Position Sensor adjustment
incorrect Replace with Throttle Valve ASM
Throttle Position Sensor circuit open
or shorted Correct or replace
Cylinder head gasket damaged Replace
Engine overcooling Thermostat defective Replace (Use a thermostat set to
open at 82
C (180
F))
Engine lacks compression ———— Refer to Hard Start
Others Tire inflation pressure abnormal Adjust to recommended pressures
Brake drag Adjust
Clutch slipping Adjust or replace
Level of oil in engine crankcase too
high Correct level of engine oil
EGR valve defective Replace

ENGINE MECHANICAL (6VE1 3.5L) 6A-17
Engine Oil Consumption Excessive
Symptom Possible Cause Action
Oil leaking Oil pan drain plug loose Retighten or replace gasket
Crankcase fixing bolts loosened Retighten
Oil pan setting bolts loosened Retighten
Oil pan gasket broken Replace gasket
Front cover retaining bolts loose or
gasket broken Retighten or replace gasket
Head cover fixing bolts loose or
gasket broken Retighten or replace gasket
Oil filter adapter cracked Replace
Oil filter attachings bolt loose or
rubber gasket broken Retighten or replace oil filter
Oil cooler broken Replace
Crankshaft front or rear oil seal
defective Replace oil seal
Oil pressure unit loose or broken Retighten or replace
Blow–by gas hose broken Replace hose
Positive Crankcase Ventilation Valve
clogged Clean
Engine/Transmission coupling failed Replace oil seal
Oil leaking into combustion chambers
due to poor seal in valve system Valve stem oil seal defective Replace
Valve stem or valve guide worn Replace valve and valve guide
Oil leaking into combustion chambers
due to poor seal in cylinder parts Cylinders and pistons worn
excessively Replace cylinder body assembly and
pistons
Piston ring gaps incorrectly
positioned Correct
Piston rings set with wrong side up Correct
Piston ring sticking Replace cylinder body assembly and
pistons
Piston ring and ring groove worn Replace pistons and others
Return ports in oil rings clogged Clean piston and replace rings
Positive Crankcase Ventilation
System malfunctioning Positive Crankcase Ventilation Valve
clogged Clean
Others Improper oil viscosity Use oil of recommended S.A.E.
viscosity
Continuous high speed driving and/or
severe usage such as trailer towing Continuous high speed operation
and/or severe usage will normally
cause increased oil consumption

6A-18 ENGINE MECHANICAL (6VE1 3.5L)
Fuel Consumption Excessive
Symptom Possible Cause Action
Trouble in fuel system Mixture too rich or too lean due to
trouble in fuel injection system Refer to “Abnormal Combustion"
Fuel cut function does not work Refer to “Abnormal Combustion"
Trouble in ignition system Misfiring or abnormal combustion due
to trouble in ignition system Refer to “Hard Start" or “Abnormal
Combustion"
Others Engine idle speed too high Reset to Section 6E
Returning of accelerator control
sluggish Correct
Fuel system leakage Correct or replace
Clutch slipping Correct
Brake drag Correct
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Lubrication Problems
Symptom Possible Cause Action
Oil pressure too low Wrong oil in use Replace with correct engine oil
Relief valve sticking Replace
Oil pump not operating properly Correct or replace
Oil pump strainer clogged Clean or replace strainer
Oil pump worn Replace
Oil pressure gauge defective Correct or replace
Crankshaft bearing or connecting rod
bearing worn Replace
Oil contamination Wrong oil in use Replace with correct engine oil
Oil filter clogged Replace oil filter
Cylinder head gasket damage Replace gasket
Burned gases leaking Replace piston and piston rings or
cylinder body assembly
Oil not reaching valve system Oil passage in cylinder head or
cylinder body clogged Clean or correct

ENGINE MECHANICAL (6VE1 3.5L) 6A-19
Engine Oil Pressure Check
1. Check for dirt, Fuel or water in the engine oil.
a. Check the viscosity of the oil.
b. Check the viscosity of the oil.
c. Change the oil if the viscosity is outside the
specified standard.
d. Refer to the “Maintenance and Lubrication"
section of this manual.
2. Check the engine oil level.
The level should fall somewhere between the
“ADD" and the “FULL" marks on the oil level
dipstick.
If the oil level does not reach the “ADD" mark on
the oil level dipstick, engine oil must be added.
3. Remove the oil pressure unit.
4. Install an oil pressure gauge.
5. Start the engine and allow the engine to reach
normal operating temperature (About 80C).
6. Measure the oil pressure.
Oil pressure should be:
392




550 kPa (56.9




80.4 psi) at 3000 rpm.
7. Stop the engine.
8. Remove the oil pressure gauge.
9. Install the oil pressure unit.
10. Start the engine and check for leaks.

6A-84 ENGINE MECHANICAL (6VE1 3.5L)
NOTE: Do not allow the crankshaft to rotate.
5. Remove the rod caps.
6. Measure the width of the plastigage and determine
the oil clearance. If the oil clearance exceeds the
limit, replace the rod bearing as a set.
Standard : 0.019 mm




0.043 mm
(0.0007 in




0.0017 in)
Limit : 0.08 mm (0.003 in)





015RS008
7. Clean the plastigage from the bearings and the
crankshaft pins.
Con




rod Bearing Selection
Select and install the new connecting rod bearings,
paying close attention to the connecting rod big end
diameter size mark (1).
NOTE: Take care not to confuse the alignment mark (2)
and the size mark (1) during the installation procedure.





015RS034


1 Size Mark Big end Bore
Diameter Crankshaft Pin
Diameter Connecting Rod
Bearing Thickness
(Reference) Color of
Size Mark Oil Clearance
(Reference)
A 56.994-57.000
(2.2439-2.2441) 1.512-1.516
(0.0595-0.0597) Yellow 0.025-0.054
(0.0010-0.0021)
B 56.988-56.994
(2.2436-2.2439) 53.922-53.937
(2.1229-2.1235) 1.508-1.512
(0.0594-0.0595) Green 0.027-0.056
(0.0011-0.0022)
C 56.982-56.988
(2.2434-2.2436) 1.504-1.508
(0.0592-0.0594) Pink 0.029-0.058
(0.0011-0.0023)

Reassembly
1. Install connecting rod
2. Install piston
3. Install piston pin

Apply a thin coat of engine oil to the piston pin.
Try to insert the piston pin into the piston pin
hole with normal finger pressure.
NOTE: When changing piston / connecting rod
combinations, do not change the piston / piston pin
combination and do not reuse the old piston pin.

Attach the piston to the connecting rod with the
piston front mark and the connecting rod fron
t
mark on the same side.

6A-88 ENGINE MECHANICAL (6VE1 3.5L)
Disassembly
1. Remove cylinder head assembly.
2. Remove cylinder head gasket.
3. Remove crankcase with oil pan.
4. Remove oil pipe and O-ring.
5. Remove oil strainer and O-ring.
6. Remove oil pump assembly.
7. Remove crankcase side bolts.
8. Remove oil gallery.
9. Remove piston and connecting rod assembly.
10. Remove flywheel.
11. Remove rear oil seal retainer assembly.
12. Remove main bearing cap.
13. Remove crankshaft.
14. Remove cylinder block.
Inspection and Repair
1. Remove the cylinder head gasket and any other
material adhering to the upper surface of the
cylinder block. Be very careful not to allow any
material to accidentally drop into the cylinder block.
Be very careful not to scratch the cylinder block.
2. Carefully remove the oil pump, rear oil seal
retainer, and crankcase assembly installation
surface seal.
3. Wipe the cylinder block clean.
4. Visually inspect the cylinder block. If necessary,
use a flaw detector to perform a dye penetrate and
hydraulic (or air pressure) test. If cracking or othe
r
damage is discovered, the cylinder block must
either be repaired or replaced.
Flatness
1. Using a straight
edge and feeler gauge, check
that the upper surface of the cylinder block is no
t
warped.
NOTE: Be very careful not to allow any material to
accidentally drop into the upper surface of the cylinde
r
block. Be very careful not to scratch the upper surface
of the cylinder block.
2. The cylinder block must be reground or replaced i
f
the warpage exceeds the limit.
Warpage
Limit : 0.15 mm (0.0059 in)
Maximum repairable limit: 0.15 mm (0.0059 in)




012RS004
Cylinder Bore
Use a cylinder gauge to measure the cylinder bore
diameter in both the axial and thrust directions. Each
measurement should be made at six points.
CAUTION: Be very careful not to allow any material
to accidentally drop into the upper surface of the
cylinder block. Be very careful not to scratch the
upper surface of the cylinder block.
Cylinder Bore Inside Diameter
Limit : 93.530 mm (3.6823 in)
If the measurement exceed the specified limit, the
cylinder block must be replaced.
Diameter
Grade A : 93.400 mm




93.410 mm
(3.6772 in




3.6776 in)
Grade B : 93.411 mm




93.420 mm
(3.6776 in




3.6779 in)
Grade C : 93.421 mm




93.430 mm
(3.6780 in




3.6783 in)

6B-6 ENGINE COOLING (6VE1 3.5L)
Draining and Refilling Cooling
System
Before draining the cooling system, inspect the system
and perform any necessary service to ensure that it is
clean, does not leak and is in proper working order.
The engine coolant (EC) level should be between the
“ MIN" and “MAX" lines of reserve tank when the engine
is cold. If low, check for leakage and add EC up to the
“ MAX" line.
There should not be any excessive deposit of rust o
r
scales around the radiator cap or radiator filler hole, and
the EC should also be free from oil.
Replace the EC if excessively dirty.
1. Completely drain the cooling system by opening the
drain plug at the bottom of the radiator.




P1010064
2. Remove the radiator cap.
WARNING: To avoid the danger of being burned, do
not remove the cap while the engine and radiato
r
are still hot. Scalding fluid and steam can be blown
out under pressure.
3. Disconnect all hoses from the EC reserve tank.
Scrub and clean the inside of the reserve tank with
soap and water. Flush it well with clean water, then
drain it. Install the reserve tank and hoses.
4. Refill the cooling system with the EC using a
solution that is 50 percent antifreeze.
Procedure for filling with coolant (in case of full change)
 Make sure that the engine is cool.
 Open radiator cap pour coolant up to filler neck.
 Pour coolant into reservoir tank up to “MAX" line.

 Tighten radiator cap and start the engine. Afte
r
idling for 2 to 3 minutes, stop the engine and reopen
radiator cap. If the water level is lower, replenish.
WARNING: When the coolant is heated to a high
temperature, be sure not to loosen or remove the
radiator cap. Otherwise you might get scalded by
not vapor or boiling water. To open the radiato
r
cap, put a piece of thick cloth on the cap and
loosen the cap slowly to reduce the pressure when
the coolant has become cooler.

After tightening radiator cap, warm up the engine at
about 2000 rpm. Set heater adjustment to the
highest temperature position, and let the coolan
t
circulate also into heater water system.
 Check to see the thermostat has opened through
the needle position of water thermometer, conduct a
5 –minute idling again and stop the engine.
 When the engine has been cooled, check filler neck
for water level and replenish if required. Should
extreme shortage of coolant is found, check the
cooling system and reservoir tank hose for leakage.
 Pour coolant into the reservoir tank up to “MAX"
line.

ENGINE COOLING (6VE1 3.5L) 6B-11
Removal
1. Disconnect battery ground cable.
2. Loosen a drain plug to drain EC.
3. Disconnect oil cooler hose on automatic transmission (A/T).
4. Disconnect radiator inlet hose and outlet hose from the engine.





P1010064
5. Remove fan guide(1), clips(2) on both sides and
the bottom lock, then remove lower fan guide(3)
with fan shroud(4).







RTW46BSH000101
6. Disconnect the reserve tank hose(6) from radiator.
7. Remove bracket(5).





110RW004
8. Lift up and remove the radiator assembly with
hose, taking care not to damage the radiator core
with a fan blade.
Inspection
Radiator Cap
Measure the valve opening pressure of the pressurizing
valve with a radiator filler cap tester.
Replace the cap if the valve opening pressure is outside
the standard range.
Valve opening pressure kPa (psi) 93.3






122.7
(13.5






17.8)
Cap tester: 5 –8840 –0277 –0
Adapter: 5 –8840 –2603 –0
Check the condition of the vacuum valve in the cente
r
of the valve seat side of the cap. If considerable rust or
dirt is found, or if the valve seat cannot be moved by
hand, clean or replace the cap.