Gen III Pistons - There are plenty of Gen III's that have never had any oiling issues, whereas there are some that have had excessive oil consumption issues. As we all know, "Bad news" travels twice as fast as "Good news". Apparently GM has changed the piston and ring design 3 times (to suit Australian fuels and oils not USA's) to try to get the oil consumption down, without impeding power or noise. Gen III engines are quite often noisy/rattly when cold (piston or gudgeon noise), which is a result of assembly tolerances. Those types of noises should be reduced as the engine and oil warms.
Gen III Oil Problems - During a cold start-up, a GEN III should have more than 150kpa of oil pressure. If there is less than that, GMH suggest further action, which usually results in the engine being removed. Once the engine is removed, the oil pump is replaced, and the pickup tube o-ring is changed. This procedure is recommended to be carried out with the engine out of the vehicle to ensure the correct refitting of the sump.
Australian Gen III's have a front mounted oil pickup and sump design, where as the Gen III's originally (US) had a rear mounted pickup and sump design. A downside to this is that under hard acceleration, the oil pump pickup may not be submersed in enough oil, so the oil system momentarily aerates. During hard acceleration, zero or extremely low oil pressure will easily damage any crank bearings. That applies to any engine.
Gen III Oil Consumption - Oil consumption has been found to be reasonably higher than previous models, with 2.5Ltrs per 10,000Km's being the acceptable limit.
Gen III Oil leaks - On the front left edge of the engine sump, there is a oil pan transfer cover (just above the oil filter). Some Gen III's may leak oil from this area. A possible caused can be porosity in the oil pan transfer cover stud holes. A revised sump was introduced early in 2000. O-Rings were added to the oil pan transfer cover studs (with a gasket as well), to help reduce leaks from this area. In some situations, the sump itself can be porous, and may need to be replaced.
Unfortunately, early production sumps can not have O rings fitted to them, as they have not been counter bored around the transfer cover mounting studs.
Gen III Coolant Leaks - Gen III's have a coolant crossover pipe located below and behind the radiator. The hoses were connected using spring band type clamps. In some cases, these clamps are insufficient, and coolant may leak from this area. Worm drive hose clamps for the cross-over pipe hose connections (larger radiator hoses) have been fitted to vehicles (during production) from mid 2000.
Hose Clamp - Part number 92138604
Gen III Engine Covers - Engine cover rattle at idle, or just above idle speed is common. This is caused by the engine cover contacting the coil/bracket assembly. GMH have revised the support brackets and the mounting nuts. Split covers are readily available which reduce inlet manifold temperature for better performance. In mid 2002, the brackets were again revised with bumpers, and no longer require spacer nuts.
Engine cover Insulator (front) - Part number 92086029
The engine cover may also rattle against the hydraulic clutch hose on manuals built before vin # L867194. The clutch hoses may become twisted or distorted and interfere with the engine cover. A revised clutch hose with quick-connect fittings was introduced mid 2002.
Gen III Vibration - Some VT's may suffer from an excessive vibration, which is felt within the vehicle. Vibrations may be felt when A. The vehicle is stationary with the engine idling in gear and the A/C is on , B. When the idle speed drops during automatic gear selection and/or a steering load is applied, or C. During slow acceleration or low speed driving in a low gear, with engine speed between 650 and 1000 rpm. Several areas may cause these issues. One area is the PCM calibration, which was later revised with improved idle speed control. Another area may be a stressed exhaust system. A Bent catalytic converter bracket is an indication that exhaust stress is evident (this should be straight). Spacers can be added to keep this bracket straight when bolted in place.
Rocker gear 5.0ltr V8 - Rocker gear wear is inevitable. Alloy rocker bridges and steel rockers arms wear with age, and wear increases noise and reduces valve lift. New rocker arms and bridges are available.
Petrol Filler Cap - VT's fitted with LPG need a smaller petrol filler cap (92077227, and are grey in colour), which increase the room available to remove either the LPG cap or Fuel cap.
Fuel Tank Capacities - For 1997 Models: Dry 70ltrs, When distance to empty is zero 60-64 ltrs, When low fuel warning chime sounds 58-62 ltrs. For 1998 Models: Dry 75ltrs, When distance to empty is zero 65-69 ltrs, when low fuel warning chime sounds 63-67 ltrs.