towing ISUZU TF SERIES 2004 Workshop Manual
Page 1841 of 4264
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  
  
Page 2418 of 4264
6-12 ENGINE DIAGNOSIS (C24SE) 
Engine Oil Consumption Excessive  
Condition Possible cause Correction 
Oil leaking  Oil pan drain plug loose  Retighten or replace gasket 
  Oil pan setting bolds loosened  Retighten 
  Oil pan gasket broken  Replace gasket 
  Front cover retaining bolts loose 
or gasket broken Retighten or replace gasket 
  Head cover retaining bolts loose 
or gasket broken Retighten or replace gasket 
  Oil filter adapter cracked  Replace 
  Oil filter attaching bolt loose or 
rubber gasket broken Retighten or replace oil filter 
  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 
 Engine/Transmission coupling 
area 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 Rebore cylinder and replace 
pistons and others 
  Piston ring gaps incorrectly 
positioned Correct 
  Piston rings set with wrong side 
up Correct 
  Piston rings sticking  Rebore cylinder and replace 
pistons and others 
  Piston ring and ring groove worn  Replace pistons and others 
  Return ports in oil rings clogged  Clean piston and replace rings 
Crank case ventilation, Positive 
Crankcase Ventilation System 
malfunctioning Positive Crankcase Ventilation 
Hose 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 
  
Page 2999 of 4264
MAINTENANCE AND LUBRICATION  0B-11 
SEVERE CONDITIONS MAINTENANCE SCHEDULE (For GENERAL EXPORT) 
    
Severe driving conditions   
A :  Repeated short trips 
G : Gasoline engine 
B :  Driving on rough roads 
4JA1-T : 4JA1-T Diesel engine 
C :  Driving on dusty roads 
4JA1-TC  : 4JA1-TC Diesel engine 
D :  Driving in extremely cold weather and/or on salted roads 
4JH  : 4JH1-TC Diesel engine 
E :  Towing trailer or climbing mountain frequently 
D: Diesel  engine 
  MT : Manual transmission 
  
AT : Automatic transmission 
  
4WDFour wheel drive 
  Condition 
      A B C D E A+D
Engine oil G  : Change every 5,000 km (3,000 miles) or 3 month4JA1-T  : Change every 2,500 km (1,500 miles) 4JA1-TC  : Change every 5,000 km (3,000 miles) 4JH  : Change every 7,500 km (4,500 miles)    
  
G  Replace every 5,000 km (3,000 miles) or 3 month  
   
Engine oil filter 
D  Replace every 5,000 km (3,000 miles)   
   
Exhaust system  Inspect every 5,000 km (3,000 miles) 
  
   
Air cleaner element  Replace every 20,000 km (12,000 miles) D  : Inspect every 2,500 km (1,500 miles)   
    
Steering system for looseness 
or damage Inspect every 5,000 km (3,000 miles) 
 
     
Universal joints and sleeves  Inspect for wear and lubricate every 5,000 km (3,000 
miles)  
     
Transmission or transfer case 
oil MT Change every 20,000 km (12,000 miles)  
after changing at initial 10,000 km (6,000 miles)  
     
 AT  Transmission:  
Change every 20,000 km (12,000 miles)   
 
 4WD  Transfer:  
Change every 20,000 km (12,000 miles)  
     
Differential oil  Change every 20,000 km (12,000 miles)  
after changing at initial 10,000 km (6,000 miles)  
     
Front brake pads and discs  Inspect every 5,000 km (3,000 miles) 
     
Rear brake lining and drum 
wear Inspect every 5,000 km (3,000 miles) 
     
Interval Item  
Page 3000 of 4264
0B-12  MAINTENANCE AND LUBRICATION 
SEVERE CONDITIONS MAINTENANCE SCHEDULE (For EUROPE) 
Severe driving conditions 
4JA1-TC  : 4JA1-TC Diesel engine 
A: Repeated short trips 
4JH  : 4JH1-TC Diesel engine 
B:  Driving on rough roads 
D : Diesel engine 
C:  Driving on dusty roads 
MT : Manual transmission 
D:  Driving in extremely cold weather and/or on salted roads 
AT : Automatic transmission 
E:  Towing trailer or climbing mountein frequently 
4WD : Four wheel drive 
  
Condition 
Item Interval 
A B C D A+D
Engine oil 4JH   : Change every 5,000 km (3,000 miles) 4JA1-TC  : Change every 7,500 km (4,500 miles)   
 
Engine oil filter 4JH  : Replace every 5,000 km (3,000 miles) 4JA1-TC  : Replace every 7,5000 km (4,500 miles)   
 
Exhaust pipes and mounting  Inspect every 10,000 km (6,000 miles) 
   
 
Air cleaner element  Replace every 20,000 km (12,000 miles) 
  
  
Steering system for looseness or 
damage Inspect every 5,000 km (3,000 miles) 
 
    
Universal joints and sleeves  Inspect for wear and lubricate every 10,000 km (6,000 miles)   
   
Transmission or transmission 
with transfer case oil MT Change every 30,000 km (18,000 miles)  
after changing at initial 10,000 km (6,000 miles)  
    
 AT
 Transmission:  
Inspection every 20,000 km (12,000 miles)    
 4WD  Transfer:  
Change every 30,000 km (18,000 miles) 
After changing at initial 10,000 km (6,000 miles)  
    
Differential oil  Change every 20,000 km (12,000 miles)  
after changing at initial 10,000 km (6,000 miles)  
     
Front brake pads and discs  Inspect every 5,000 km (3,000 miles) 
    
Rear brake lining and drum wear  Inspect every 5,000 km (3,000 miles)