10/1/2002
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Is it normal for a customer to lose up to a quart of oil every 2,000 miles?
Q. Is it normal for a customer to lose up to a quart of oil every 2,000 miles?
A. Surprisingly, if your customer is driving a 1999-2002 GM truck with the 4.8L V8 (also known as the Vortec 4800), the answer is "yes." General Motors says oil consumption of this magnitude under normal operating conditions is perfectly normal for these engines. However, a new fixed orifice PCV valve (p/n 12572717) is now available.
GM offers these suggestions:
Verify that the oil consumption is not the result of an oil leak or any other engine concern.
Perform an oil consumption test. GM says that at least 4,000 miles should be driven before the oil consumption rate can be established.
Remove the PCV valve and inspect the hose going to the intake manifold for signs of excessive oil.
If excessive oil is found in the hose, replace the PCV with a new style valve.
Figure 1 (above right) shows the difference between the older style spring and plunger type and the revised new style fixed orifice valve. The fixed orifice PCV valve has no moving parts and will not rattle when shaken. If a new style valve has already been fitted, oil consumption may be due to other causes.
Q. How can I determine which of the Toyota 1.8L engines I’m working on?
A. The AERA Technical Committee offers the following information on a crankshaft "caution" for 2000 Toyota 1.8L engines. During the 2000 year Toyota offered two engines with similar displacement, a 1ZZ-FE and a 2ZZ-GE designation. Determining which engine you’re working on may be confusing, as many components are similar. The crankshafts for these engines share similar main journal diameters, but the rod journal diameters differ.
The main journal diameter of both crankshafts is 1.8893˝-1.8898˝ (47.988 mm-48.000 mm). The connecting rod journal diameter for the1ZZ-FE is 1.7320˝-1.7323˝ (43.992 mm-44.000 mm), while the 2ZZ-GE engine has a larger 1.7713˝-1.7717˝ (44.992 mm-45.000 mm) rod journal diameter.
Other engine differences include bore and stroke dimensions. The 1ZZ-FE engine has a 79 mm bore and 91.5 mm stroke (1794 cc), while the 2ZZGE engine has a larger 82.0 mm bore and smaller 85.0 mm stroke (1762 cc).
There are also slight clearance specification variations between the different engines so determining which engine is being worked on and obtaining the correct specifications is crucial.
Q. How would I know which MerCruiser engine has a bad pushrod from the factory?
A. According to the AERA Technical Committee, some GMC MerCruiser engines were produced with defective pushrods. Apparently, the pushrods used in some MCM 496 MAG HO stern drive and MIE 8.1S HO inboard engines made between 1993-’97 (see Figure 2) "missed a step" during the machining operation which causes interference and results in pushrod failure.
Some of these engines were repaired at the factory, as indicated by a white mark visible on the brass fitting on the top port (left) side of the heat exchanger that connects the hose from the heat exchanger to the overflow bottle.
All others can be repaired by installing new pushrods (MerCruiser p/n 881682A-1 intake and p/n 881683A-1 exhaust) and noting that the latter are slightly longer. Reinstall the rocker assemblies, lubricate and torque the rocker nuts to 19 ft.lbs. (25 Nm).