| OIL LEAKS ON 1984-86 GM 2.8L ENGINES USED IN AMC |
Oil Leaks On
1984-86 Chrysler (AMC) 2.8L (173 CID) Engines Used In Jeep
Applications
Chrysler (AMC) says there are three possible oil leak locations
on its 2.8L (173 CID) engines: the valve covers, intake manifold
and rear cradle area of the oil pan.
Replace leaking valve cover gaskets with AMC part #8983 503 179
or aftermarket equivalent. The seam where the intake manifold
and cylinder head mate must have a small amount of RTV sealer
applied to eliminate gaps or steps that will allow leaks. Gasket
over-crush is prevented by metal pins located on the side of each
bolt hole.
Intake manifolds usually leak at the rear manifold-to-block
mating surface. After removing the manifold and thoroughly
cleaning it, use a 3/16 (4.7mm) diameter spherical cutter
(Figure 1) to cut a 3/16 (4.7mm) wide groove that's 1/16
(3.1mm) to 1/8 (1.5mm) deep.
(Insert Illustration)
Fill the groove with RTV sealer when reinstalling the manifold
(Figure 2).
(Insert Illustration)
For 1984 engines, Chrysler (AMC) supplies an oil pan gasket kit
AMC part #8983 500 853 (or use an aftermarket equivalent), which
should be installed in place of the RTV sealer used at the
factory. It is important, however, to seal the rear cradle
corners with RTV sealant.
1985-86 engines should be closely inspected for deformed oil pans
(Figure 3). Replace deformed oil pans with AMC part #8953 001
840. Engines built after January 21, 1986 should not have
deformed oil pans.
(Insert Illustration)
The new, recommended method is to remove the stand-offs on the
oil pan rails (Figure 4) with a file or small hand-grinder. Use
AMC oil pan gasket kit #8983 500 853 or aftermarket equivalent.
(Insert Illustration)
The rear cradle seal is installed in the groove in the main cap
and a small amount of RTV is applied to the corners of the seal
where it contacts the block. Please note that once the stands
have been removed, RTV can no longer be used in place of the
gasket.
The AERA Technical Committee
August 1986 - SB 134
##END## |
| VALVE SEAT INSTALLATION CAUTION |
Valve Seat Installation Caution On
Chrysler 4.0L Engines
AERA members have reported coolant loss on Chrysler 4.0L engines used in the Jeep vehicles. This loss occurs shortly after cylinder head remanufacture and can vary in amounts.
If exhaust valve seats are installed during cylinder head rebuild process, the counterbore tool may break into the coolant passages of the head. A valve seat counterbore as small as 1.500 outside diameter by .218 deep may create a through passage. Although each individual head casting may vary in casting thickness in this area, caution should be used in seat selection. Pressure
checking the head after seat installation is advised.
If a seat is installed into the number one cylinder, you may be able to see the newly created passage by looking through the thermostat housing opening at the very front of the head (see illustration).
The AERA Technical Committee |
| DISENGAGED PUSHRODS ON AMC 4.2L ENGINES |
Pushrod Problems On
1981-82 Chrysler (AMC & Jeep) 4.2L (258 CID) 6 Cyl. Engines
Pushrods in some 1981-82 Chrysler (AMC & Jeep) 4.2L (258 CID) 6 cyl. engines built prior to May, 1982, may disengage from the rocker arms causing noise, backfire or a miss.
To correct this problem, install a complete set of .070 longer replacement pushrods if any of the original parts become disengaged or bent.
The original pushrods are 9.640 to 9.660 long. (Part No.3227329)
Replacement pushrods are 9.710 to 9.730 long. (Part No.3242395)
NOTE: The original shorter pushrods (Part No. 3227329) are stillrecommended for use in 1980 and prior Chrysler (AMC & Jeep) 4.2L (258 CID) engines.
The AERA Technical Committee |
| KNOCKING NOISE |
Engine Noise Diagnosis On
1981 Chrysler (Jeep) CJ Models With 4 Cylinder Engines
The 4 cylinder engines used in 1981 Chrysler (Jeep) CJ models generally produce a higher level of operating noise than the 1981, 6 cylinder engines. This is due to design differences that primarily affect operating clearances. For example, cold engine piston slap or knock that ceases after a few minutes of operation is normal on 1981 Jeep 4 cylinder engines.
Because some engine operating noise is normal,, it is important that this fact be taken into consideration when diagnosing suspected engine noise. Some known sources of abnormal engine noise are: excessive piston-to-cylinder wall clearance; excessive connecting rod bearing clearance; carbon buildup on piston; loose or improperly seated camshaft or crankshaft sprockets and loose
torque converter-to-drive plate attaching bolts.
Correction of a 4 cylinder noise condition should be performed only after the noise has been determined to be abnormal and the source of the noise pinpointed through careful diagnosis. The diagnosis procedures for the above mentioned sources of abnormal engine noise are as follows:
Connecting Rod Bearing/Torque Converter Bolt Noise
Connecting rod bearing noise (knock) caused by excessive bearing clearance is generally noticeable when the engine is not under load. Loose torque converter bolts can also produce a noise similar to connecting rod bearings with excessive clearance.
However, converter bolt noise is generally more noticeable when the transmission is in Neutral and engine is operating at fast idle speed. This noise may, or may not be noticeable when the transmission is in gear and the engine at idle speed.
(1) If noise is most noticeable with transmission in Neutral and after throttle is opened and closed rapidly several times, check for loose torque converter bolts. Remove any loose bolts, apply Locktite 271, or equivalent and install and tighten bolts to 40 foot pounds (54 N·m) torque.
(2) If noise is most noticeable with transmission in gear and engine is not under load, check connecting rod bearing clearance. If clearance is excessive, 0.001 or 0.002 undersize bearings may be installed.
Piston Slap/Carbon Knock
Piston slap caused by excessive piston-to-cylinder wall clearance occurs in both low and high mileage engines. Carbon knock is more likely to occur on high mileage engines, but may also occur on low mileage. Carbon knock is not sensitive to engine load and is most noticeable when the engine is not under load. Carbon knock may be loudest when the engine is cold and may continue
even after the engine warms up.
NOTE: Cold engine piston slap that ceases after a few minutes operating time is normal on 1980-81 Jeep 4 cylinder engines.
(1) If noise is not sensitive to engine load, clean engine piston tops and combustion chambers with AMC combustion chamber cleaner or equivalent.
(2) If noise ceases after using combustion chamber cleaner, return automobile to owner.
(3) If noise does not cease, check piston-to-cylinder wall clearance. if clearance is excessive, pistons may be knurled to provide desired clearance. However, if knurling service is not readily available, 0.005 oversize piston and ring sets may be installed to obtain desired clearance.
NOTE: Piston-to-wall clearance should be 0.0027 - 0.0033 (0.0635 - 0.0838mm). Measure piston diameter at the pin centerline 1-3/16 below the piston pin (on the piston skirt). Measure the cylinder bore at a point 2-1/4 below the top of the bore. Cylinder taper should be no more than 0.001 (0.0508mm).
Camshaft/Crankshaft Sprocket Noise
Loose or incorrectly seated camshaft or crankshaft sprockets are generally noticeable when the engine is warm. Sprocket noise is sensitive to engine speed, but not load. Sprocket noise is also evident at warm idle and sounds similar to a loose timing chain.
(1) Remove accessory drive belts and position sound detection tool on timing pointer to verify noise.
(2) If sprocket noise is detected, repair or replace camshaft or crankshaft sprockets.
The AERA Technical Committee |
| REVISED CYLINDER HEAD GASKET |
Revised Cylinder Head Gasket On
Chrysler/Jeep 4.0L (VIN L,M,S) Engines
Chrysler Corporation has revised the cylinder head gasket on 1987-93 Jeep 4.0L engines. There have been reported problems of coolant and oil seepage at the cylinder head and block joint on the right (camshaft side) of the engine.
The revised design gasket incorporates beaded silicone sealer on both sides of the gasket to eliminate the seepage problem. The Chrysler part number for the improved gasket is 53020219. Chrysler recommends the use of the improved gasket during any repairs requiring removal of the cylinder head.
The AERA Technical Committee |
| CAUTION ON SURFACING CYLINDER HEADS & BLOCKS |
Caution On Resurfacing Cylinder Head And Block on
Chrysler 3.8L L6 OHC (Kaiser Jeep) Engine
The cylinder head and engine block mating surfaces of the Tornado 6-230 OHC engine should never be machined or planed. By way of explanation, the practice of resurfacing which is common with many other engines, upsets the carefully controlled tolerance between the center lines of the camshaft and the crankshaft.
Machining these surfaces can retard the timing to an extent that could definitely affect engine operation.
The AERA Technical Committee |
| ENGINE OVERHEATING ON JEEP 4.0 |
Engine Overheating Complaints On
Chrysler 4.0L (Jeep) Engines
AERA members have reported several instances of overheating complaints on Chrysler/Jeep vehicles equipped with 4.0L engines.
This cooling system is very susceptible for trapping air after the radiator or engine has beens serviced. Even though an air bleed system is provided, air can remain in the cooling system causing an overheat condition.
The best way to fill the system is to pump coolant into the system through a heater hose. Attempting to fill the system through the radiator cap is often traps air in the system. Members report raising the front of the vehicle while the cooling system is being filled also helps.
The AERA Technical Committee |
| REAR MAIN SEAL LEAKAGE ON 1997-20005 CHRYSLER 4.0L ENGINES |
Rear Main Seal Leakage, Preventative Measure For
1997-2005 Chrysler 4.0L VIN S Engines
The AERA Technical Committee offers the following preventative measure for 1997-2005 Chrysler 4.0L Jeep engines. This information applies to engines using a standard shift transmission built prior to 09/02/04 only.
There have been occasional reports of rear main seal leakage on certain vehicles using the above combination. Closer inspection of suspect vehicles may reveal the cause of the engine oil seepage past the rear main seal is due to the accumulation of dirt and debris around the outside of the rear main seal. This accumulation may act as an abrasive while rotating on the crankshaft and damage the seal and surface.
A spacer plate is used to mate the transmission bellhousing to the back of the engine. The spacer plate has a slot machined into it at the 12 o?clock position. A small opening may occur as a result of the spacer slot when the spacer is mated between the engine and transmission bellhousing. The narrow spacer opening at the top may allow small size debris to accumulate around the outside of the rear main crankshaft seal. Vehicles used in dusty off road situations have been more severely affected.
To prevent this type of condition, seal the area at the time of engine installation on remanufactured engines. Chrysler/Jeep has suggested this type of repair after the rear seal and or crankshaft has been repaired by applying a liberal bead of RTV sealer to the area. Make sure to thoroughly clean the area before applying the sealer to area 2 in the Figure 1 below.
The AERA Technical Committee |
| PISTON KNOCKING NOISE |
Piston Knocking Noise On
1991-94 Chrysler 2.5 & 4.0L Engines
AERA members have reported knocking noises on 1991-94 Chrysler 2.5 & 4.0L engines used in various Jeep vehicles. This noise is most noticeable at idle and may be heard on both hot or cold engines. Excessive piston to cylinder bore clearance is the cause for this noise.
Chrysler revised the piston design for this engine during the 1994 model year. The new piston has a moly coating on the skirt. Since the black moly coating varies in thickness, it is difficult to accurately determine the diameter of the piston.
To correctly select the piston for this engine, cylinder bore measurements must be recorded within .0001 (.0025 mm). Use the chart below to help determine the size piston required for each cylinder. Presently, Chrysler is offering pistons only as a piston and connecting rod assembly.
Cyl. Bore Size Piston Size Piston & Rod Assembly Part
Number
3.8759-3.8763 B 4773157
3.8763-3.8767 C 4773158
3.8767-3.8771 D 4773159
3.8771-3.8775 E 4773456
3.8775-3.8779 F 4773568
3.8779-3.8783 G 4778843
3.8783-3.8787 H 4778843
The AERA Technical Committee |
