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ENGINE NOISE ON 1983-92 ENGINES | Engine Noise On Mitsubishi
1983-92 1.6, 1.8, 2.0, 2.4L Engines
AERA members have reported engine noise on 1983-92 Mitsubishi four cylinder engines. This noise is most noticeable at cold engine start-up and is loudest in the timing cover area. It has been described as a high pitched whine and may be coming from the engine's oil pump.
To help reduce this type of noise, a revised oil pump is now available. This new pump uses a helical gear set, compared to the previous spur type gears (see illustration below). To purchase an improved design oil pump, a new case assembly and two individual gears must be ordered. Those components are also different for the various engines and cannot be intermixed with each other or the previous design.
Part Number Part Description Usage Vehicle
MD170852 Front Case Assembly 2.0L SOHC 1989-92 Galant
2.4L SOHC 1992 Expo
MD170854 Front Case Assembly 1.8L SOHC 1983-88 Cordia &
Tredia
2.0L SOHC 1984-88 Cordia &
Tredia
2.4L SOHC 1985-92 Galant,
Pickup & Van/Wagon
MD175762 Front Case Assembly 2.0L DOHC 1989-92 Galant
2.0L DOHC 1990-92 Eclipse
MD179151 Front Case Assembly 1.6L DOHC 1989-92 Mirage
MD174580 Oil Pump Drive Gear 1.8L SOHC 1983-88 Cordia &
Tredia
2.0L SOHC 1984-88 Cordia &
Tredia
2.4L SOHC 1985-92 Galant,
Pickup & Van/Wagon
MD174581 Oil Pump Drive Gear 1.6L DOHC 1989-92 Mirage
2.0L SOHC 1989-92 Galant
2.0L DOHC 1989-92 Galant,
Eclipse
2.4L SOHC 1992 Expo
MD174582 Oil Pump Driven Gear Used in all applications
listed above.
All engines built from engine build code LX8939 and up have been assembled with the new oil pump components.
The AERA Technical Committee | |
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 | |
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 | |
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 | |
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
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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 | |
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 | |
WARM ENGINE KNOCKING NOISE | Warm Engine Knocking Noise On
Chrysler 3.0L SOHC (MMC) Engines
The AERA Technical Committee has received reports of knocking noises at operating temperature on Chrysler 3.0L SOHC engines. The knock is most noticeable when operating under light to mediumacceleration. Subsequent disassembly of these engines could notlocate any apparent engine damage or mechanical cause for thenoise.
Chrysler has issued the following diagnostic information that pertains to this knocking that may be mistakenly diagnosed as a bearing failure. Only use this procedure if the knock occurs at operating temperature. Do not use this procedure if the knock occurs when the engine is cold.
Using the appropriate scan tool, verify that all systems are functioning properly and that no fault codes are present. Disconnect the #2 injector and raise the engine RPM to 1,700-2,000 rpm. If the engine noise is eliminated or diminished
considerably, the Single Board Engine Controller (SBEC) needs to be replaced with an updated version.
The appropriate SBEC is available from Chrysler and is distinct to the vehicle application, year and VIN. Chrysler 3.0L SOHC engines are manufactured by Mitsubishi Motors Corporation and used in various vehicles.
For additional information see AERA Technical Bulletins: TB-988 & ES-25
The AERA Technical Committee | |
VALVE TRAIN CLATTER | Continued Valve Train Clatter On
1989-92 Chrysler 2.0L DOHC (VIN R,U)
The AERA membership has experienced many instances of valve train clatter on the Chrysler 2.0L DOHC engines manufactured by Mitsubishi. These noises can be attributed to adjuster sounds that do not stop even after the engine has been running for some time.
This engine, as well as many other overhead cam (OHC) engines, uses hydraulic lash compensators (HLC) to maintain zero (0) lash between the camshaft follower, camshaft lobe and valve tip. If the valve train itself is within wear limits, there are two other possibilities that can lead to continued valve train clatter. They are:
1) A low oil level in the engine, permitting air to be drawn into the oil pump.
2) An oil level that is too high, where oil is stirred by the crankshaft and
mixed with large amounts of air.
In either case, the engine's high pressure oil supply is being mixed with air. If aerated oil enters the high-pressure chamber of the lash compensator assembly, the air will become trapped. As the valve opens, the air is compressed creating abnormal noise when the valve closes. This is similar to excessive dry lash clearance.
The solution to this problem (once the oil level has been verified) is to slowly race the engine up to ten times. Gradually increase the engine speed from idle to 3,000 rpm (hold for 30 seconds), and then gradually slow to idle speed (for 30
seconds). If the abnormal and continued valve train clatter cannot be eliminated, replacement of the hydraulic unit is recommended.
This situation (aeration) may also occur if the vehicle is parked on a slope and restarted. Another possibility exists if the vehicle has been in storage for an extended period.
The AERA Technical Committee | |
BALANCE SHAFT TIMING | Balance Shaft Timing Caution On
Chrysler 2.0L (MMC) Engine
The AERA Technical Committee has had reports of a drone or buzz noise on Chrysler 2.0L engines that appeared after the engine had been remanufactured. This engine is manufactured by Mitsubishi Motors Corporation and is used in several of their vehicles as well as several automobiles marketed by Chrysler
Corporation.
AERA Members experiencing this problem should pay close attention to the timing of the counter balance shafts. Unlike the 2.6L engine, which is virtually impossible to assemble incorrectly, the 2.0L may have the lower shaft 180° out of phase. The result is excessive secondary harmonics which will emit a drone or a buzz noise. One of the reports described it as a vibration
that goes through the accelerator and can be felt by the foot of the driver.
The procedure for correct timing of the balance shafts requires an inspection plug to be removed on the left side of the block. Insert a .31 (8 mm) diameter screwdriver through the opening (see illustration). Rotate the balance shaft until the screwdriver can be inserted at least 2.36 (60 mm) into the opening. The lower balance shaft is now properly timed.
Keep the screwdriver in place while indexing the rest of the timing components. Finally, remove the screwdriver and replace the inspection plug.
The AERA Technical Committee |
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