| EXCESSIVE OIL CONSUMPTION |
Excessive Oil Consumption
on 1978-89 Chrysler Jet Valve Engines
AERA members have reported excessive oil consumption and spark plug fouling complaints on 1978-89 Chrysler jet valve engines. These engines are manufactured for Chrysler Corporation by Mitsubishi Motor Corporation of Japan.
There are several possibilities for allowing oil to pass into the combustion chamber. They are oil leaking past the valve stem seal or the jet valve body O-ring, or a worn jet valve body or valve stem. Since oil can travel among the various air passages in the cylinder head casting, it is important to inspect all jet valves not just the cylinder that is indicated by a fouled spark plug.
Remove the jet valve assembly as indicated in the appropriate service manual and inspect the O-ring for nicks, cuts, tears or deformation. Likewise, a brittle O-ring is not capable of sealing out lubricating oil. The O-ring, Chrysler part #MD009786, should be replaced whenever the jet valve assembly is removed from the cylinder head.
Disassemble the jet valve assembly and inspect the valve stem seal for damage or deformation. Chrysler recommends replacement of the complete assembly if the valve body or valve stem are worn. Use Chrysler part #MD009440.
Any oil residue or carbon must be removed from the jet valve passages before assembly. See the appropriate OE or aftermarket manual for further information and torque values.
The AERA Technical Committee |
| VALVE STEM SEAL IDENTIFCATION ON MITSUBISHI 3.0L ENGINES |
Valve Stem Seal Identification On
2000-02 Mitsubishi 3.0L VIN H Engines
AERA members have reported a difficulty correctly identifying valve stem seals on 2000-02 Mitsubishi VIN H engines. To properly identify the two different valve stem seals, Mitsubishi has color-coded the seals.
Upon removing the valve seals from the packaging, there may not be any identification sheet with the seals. This leaves the machinist wondering which seal goes on the intake valve and which one on the exhaust valve. To correctly install these seals, the one with charcoal gray identification color goes on the exhaust and the one with the green identification color goes on the intake.
Color Location Part #
Charcoal Gray Exhaust MD184303
Green Intake MD307342
AERA is currently unaware of an aftermarket supplier of the valve stem seals mentioned above.
The AERA Technical Committee |
| BURNED JET VALVES |
Burned Jet Valves On
Chrysler (Mitsubishi) 2.6L Engines
The AERA Technical Committee offers the following consideration for Chrysler 2.6L engines with repeated jet valve burning problems. This problem is most prevalent with engines that utilize hydraulic lash compensators (HLC). Reported failures have usually been shortly after cylinder head installation or
compensators replacement.
Unless the jet valves are readjusted after the engine has reached operating temperature, improper clearances will result. The correct lash adjustment of .010 (.254mm) can only be achieved of the HLC plunger is in its operating location. If the jet valve is adjusted before that point, or on the bench, operating oil pressure will change the previous clearance. Insufficient clearance may hold the jet valve off the seat and eventually burn it.
The AERA Technical Committee |
| REVISED CRANK ON 92-96 2.0L ENGINES |
Revised Crankshaft On
1992-96 Mitsubishi 2.0L Engines
AREA members have reported a revised crankshaft on 1992-96 Mitsubishi 2.0L engines. The area of revision is the thrust width and flywheel flange. At first glance, the crankshaft would appear to be the same as previous crankshafts.
Modification to the thrust area of the crankshaft involved reducing the length by approximately .130 (3.302 mm). The number of flywheel mounting bolt holes was also increased from six, to seven. It also appears, that the length of all other main bearing journals has been reduced slightly.
Years Used Thrust Length Number Of Rear Bolt Holes
1983-91 1.144 (29.58 mm) 6
1992-96 1.013 (25.53 mm) 7
Currently, main bearings sets are only available from Mitsubishi.
The AERA Technical Committee |
| CORRECT CYLINDER BLOCK OIL GALLEY PLUG |
Correct Cylinder Block Oil Galley Plug On
2.6L Chrysler (MMC) Engines
The AERA Technical Committee has learned that installing the incorrect oil galley plug can lead to oil leaks. This plug is located at the rear of the cylinder block.
According to Chrysler and Mitsubishi parts catalogs, the part number is identified as a 3/8 tapered pipe plug. AERA members have reported that a 3/8 plug only catches on a couple of threads and can create an oil leak. The actual Chrysler Part #MD145018 duplicates the original factory plug and should be used for all 2.6L cylinder blocks.
The AERA Technical Committee |
| OIL IN THE COOLING SYSTEM |
Oil In The Cooling System On
1987-95 Chrysler 3.0L SOHC Engines
AERA members have reported engine oil in the cooling system on 1987-95 Chrysler* SOHC engines. The source of this condition has been determined to be coming from either of the engine's cylinder heads. The cause of this contaminated coolant is a crack in the number two cam bearing cap bolt hole. A crack in that bolt hole may connect the engines pressurized oil galley to coolant passages in the cylinder head.
The location of this crack may cause a technician to overlook this leak during pressure testing procedures. A crack in this area may not leak during pressure testing when the camshaft cap and bolt are assembled. A leak in this area, with the cam cap and bolts removed, should be repaired by plugging or welding. This bolt hole is not a drilled through hole to the coolant passage.
In some instances heating the cylinder head while pressure testing has been required to reveal this leak.
* This engine is manufactured by Mitsubishi for Chrysler.
The AERA Technical Committee |
| CAMSHAFT TIMING MARKS |
Camshaft Timing Marks On
1995 Mitsubishi 2.0L VIN Y, DOHC Engines
The AERA Technical Committee advises members of the correct camshaft
timing marks on 1995 Mitsubishi 2.0L VIN Y*, DOHC engines. The
camshaft sprockets on engines built from 8/1/94-10/31/94 have two
sets of timing marks. Those engines are also identified by the date
code sticker with numbers 057-148, as shown in Figure 1 below.
Figure 1
To position both camshaft timing sprockets for belt installation,
use only the marks adjacent to the 609 stamping. Those two marks
should be directly across from each other when properly positioned
as shown in Figure 2 below. The number one cylinder piston should
also be at top dead center.
Figure 2
The marks indicated by the 2.0L Front only show the direction of
the sprocket when properly installed. Those marks should not be used
to align the camshaft, as piston to valve interference will result
when the engine is turned over.
*This engine is manufactured for Mitsubishi by Chrysler
The AERA Technical Committee
August 1996 - TB 1370
##END## |
| REAR MAIN OIL LEAK |
Rear Engine Oil Leak On
1995 2.0 VIN C Or Y & 2.4L VIN X Chrysler Engines
AERA members have reported engine oil leaks at the rear of 1995 2.0L
VIN C or Y & 2.4L VIN X Chrysler engines. The cause of this leakage is a mis-located rear main oil seal. These engines are manufactured by the Chrysler Corporation, not the Mitsubishi Motor Company.
If the rear main oil seal is installed below flush with the rear block surface, it may place the seal's sealing lip beyond the sealing surface on the crankshaft. To properly locate and install the seal, Chrysler now offers a tool, Part #C-4681. The seal should be installed dry, positioning it and the tool over the crankshaft
and lightly tap the tool until the seal is flush with the rear of the block.
Currently this seal, Part #4667904, is available only from Chrysler.
The AERA Technical Committee |
| LOOSE VALVE GUIDES |
Loose Valve Guides On
Chrysler/Mitsubishi 2.6L Engines
The AERA Technical Committee offers the following information on loose valve guides on Chrysler/Mitsubishi 2.6L engines. It has been reported that valve guides on some cylinder heads will become loose in the parent bore after an undetermined period of time.
To restore the proper fit of the valve guide, Mitsubishi offers oversize OD (outside diameter) guides. This condition can exist on either the intake
or the exhaust valve guide. Mitsubishi offers valve guides in oversizes of .002, .010, .020. Listed below are the oversizes and the part numbers for the
oversized valve guides.
Oversize Valve Guide Part Number
.002 Intake MD020551
Exhaust MD020561
.010 Intake MD020552
Exhaust MD020562
.020 Intake MD020553
Exhaust MD020563
Aftermarket valve guide suppliers offer guides in standard and oversize OD's. Be sure to measure the new guide OD before installing as not all-oversize
diameters are offered by all aftermarket suppliers.
The AERA Technical Committee |
| ENGINE BLOCK DESIGN CHANGES |
Engine Block Design Changes On
1986 Mitsubishi 1.8, 2.0 & 2.4L Engines
The AERA Technical Committee offers the following information regarding engine design changes on 1986 Mitsubishi 1.8,2.0,2.4L engines. Changes were made to the cylinder block, balance shaft and the front case assembly in the G62, 63 & 68 engine families shortly after the start of production for the year model 1986.
The revised cylinder block now has an oil hole to provide direct lubrication to the right rear balance shaft bearing. It is visible from the outside of the block and the drilled passage is plugged with a 1/16" NPT plug as shown in Figure 1.
The balance shaft rear bearings now have a 6mm hole drilled in them for oil, whereas previous bearings did not have this hole. The front balance shaft bearing located at the engine right side has been widened by 6.5mm (See Figure 2.) The previously drilled oil holes have also been eliminated from that balance shaft.
The drive gear-bearing surface on the front case assembly has been lengthened to accommodate the longer balance shaft bearings. The oil passage diameter has also been increased as shown in Figure 3.
Caution: The new balance shaft cannot be used in the early blocks, as it does not have the required internal oil passage. Any attempt to do so would result in insufficient lubrication of the rear bearing and cause a bearing failure.
The AERA Technical Committee |
