| FRONT OF ENGINE OIL LEAKS |
Front Of Engine Oil Leaks On
1991-92 GM 1.9L Saturn Engines
AERA machine shops have reported engine oil leaks near the front crankshaft oil seal on 1991-92 GM 1.9L Saturn engines. This leak is between the seal and the pulley or damper. Both SOHC and DOHC engines have been affected from what appears to be excessive porosity of the pulley or damper.
If the leak is determined to be in this area on 1991-92 engines, pulley/damper and seal replacement may be necessary. A replacement pulley for the SOHC engine is available under Part #21000756. The DOHC engine requires a different pulley with the Part #21006009. Both engines use the same oil seal Part #21000707. Depending on the extent of the porosity, it may be possible to install a thin-wall sleeve on the pulley.
Dampers and pulleys built after VIN Code # NZ143903 in 1992 have been machined to provide a better sealing surface.
The AERA Technical Committee |
| PISTON & CONNECTING ROD ASSEMBLY |
Piston & Connecting Rod Assembly Information For
1991-99 GM 1.9L VIN 7, 8 & 9 Engines
The AERA Technical Committee offers the following piston and connecting rod assembly information for 1991-99 GM 1.9L VIN 7, 8 & 9 engines. These engines are used exclusively in Saturn vehicles. This information is to be used to update the originally published service manual contents, as it was somewhat inconclusive.
In some instances the piston used may not have a front mark indicated on the piston. In those instances view the underside of the piston and reference the rectangular casting block located on the piston pin boss. The markings on the piston pin boss should face the rear of the engine. Those markings vary in appearance depending on engine and piston application as shown in Figure 1.
It should also be noted that the piston pin retaining ring pry slot shown in Figure 1 should be toward the intake manifold for SOHC engines. On DOHC engines the two-machined eyebrows on top of the piston go toward the intake side (engine right) of the engine.
The connecting rod bearing locating lug for all engines should be toward the exhaust manifold (engine left) side of the engine when correctly assembled to the piston as shown in Figure 2.
The AERA Technical Committee |
| CYL HEAD OIL FEED MODIFIATION ON 91-92 1.9L |
Cylinder Head Oil Feed Orifice Caution On
1991-92 GM 1.9L Engines
The AERA Technical Committee cautions members on the cylinder head oiling orifice on 1991-92 GM 1.9L engines used in its Saturn vehicles. The caution expressed involves removing the existing orifice in engines built before 1993.
Apparently under certain situations, this orifice may limit the amount of oil to the cylinder head. Limited oil supply to the cylinder head may cause camshaft or lifter bore scuffing during engine start up. The amount of oil supplied to the cylinder head is controlled by a .157 (4.0 mm) opening in the head gasket.
It is therefore recommended anytime the cylinder head has been removed, that the oiling orifice be removed also. The orifice may be removed by installing a screw into it and pulling it out with a slide hammer.
The AERA Technical Committee |
| ENGINE MISS OF POPPING NOISE |
Engine Miss Or Popping Noise On
1991-97 GM 1.9L Engines VIN 8 & 9
The AERA Technical Committee offers the following information on an engine miss or popping noise on 1991-97 GM 1.9L VIN 8 & 9 engines. These vehicles
equipped with SOHC engines built before and including VIN VZ263139, either with LK0 or L24 engines, may miss or lack power under all normal engine-operating conditions. A popping noise may also be emitted through the exhaust manifold on deceleration or idle.
One cause of this condition is gum and/or carbon deposit accumulation in the exhaust valve guide(s) and on the valve stem(s). These deposits may cause an
exhaust valve(s) to stick open producing a misfire or noise. This condition may occur under all normal engine-operating conditions.
To prevent the possibility of gum or carbon deposit forming and causing the above-mentioned condition, a fuel additive is advised. Saturn suggests adding one 20 oz. bottle of Saturn fuel injector cleaner Part #21007313 or equivalent (fuel injection cleaner containing Techron) to a full tank of fuel. The fuel injector cleaner must contain Techron or gum deposits may not be removed from the valves and the valve guides. Caution: Adding a full 20 oz. bottle of injection cleaner to a partially filled gas tank may cause the fuel to create deposit formations on the valves and in the combustion chambers.
Machining the exhaust valve guide lower is also required to complete the repair. Using the service tool #SA9704E a pilot end mill and plastic stop, machine the exhaust guides from the combustion chamber side of the head. Apply pressure straight on to the guide so that no damage is done to the service tool. The plastic stop will make contact with the valve seat, shown in the figure below, when the end mill has cut the guide down. The approximate amount of guide removal is .406. For best results, oil or cutting oil should not be used. After the guide has been shortened, use a 7mm reamer or chamfering tool to remove any sharp edges left by the end mill.
The AERA Technical Committee |
| CRANKSHAFT IDENTIFICATION |
Crankshaft Identification On
1991-97 GM 1.9L VIN 7, 8 & 9 Engines
AERA members have reported some confusion identifying crankshafts for 1991-97 GM 1.9L VIN 7, 8 & 9 engines. There seems to be only one crank casting number, 21000883, but two different crankshaft designs. These engines are used in the GM Saturn vehicles.
The difference between those crankshafts is in the amount of advance of the reluctor wheel. Both versions have a notch in the reluctor wheel for direct ignition, but in the years of 1993-97 the notch is advanced 10° more than it was
in 1991-92.
To distinguish which crankshafts are advanced 10° more than the others, position the crankshaft with the snout facing you. Rotate the crankshaft until the key-way is at a three o?clock position as viewed from the crankshaft front. Then,
use twelve o?clock as a reference point and observe the location of the notches machined into the reluctor wheel. Refer to the illustrations below before proceeding.
If the double notches are about even with the left edge of the cast window of the reluctor wheel, it is a 1991-92 crankshaft. If the double notches are closer to the twelve o'clock position and approximately 1/2 to the left of the left edge of the cast window, it is the 1993-97 crankshaft. These two crankshafts should not be interchanged or driveability issues will result.
The AERA Technical Committee |
| ENGINE COOLANT LEAKS ON 1.9L DOHC SATURN ENGINES |
Engine Coolant Leaks On
2000-2001 GM 1.9L DOHC Engines
The AERA Technical Committee offers the following information on an engine coolant leak on 2000-2001 GM 1.9L DOHC engines. These engines are used in the Saturn vehicles made by GM. Vehicles affected are up to and include VIN 1Z305500. Some customers may comment about loss of engine coolant, low coolant levels and/or engine overheating.
These customer complaints may be due to the intake manifold gasket leaking. The leak may occur at the cylinder head to intake manifold coolant passage located at the rear of the number four cylinder intake port. The intake manifold seal may experience a compression set allowing an external coolant leak past the seal during cold engine operating conditions.
To solve the complaint of coolant loss, Saturn has come up with a revised intake manifold gasket for the DOHC engines. The gasket is a new 2-piece design as show in Figure 1. A separate coolant seal (1) that is made of a different material and is black in color. A shortened intake manifold gasket (2) is of the same material and orange in color like the original one-piece design.
The AERA Technical Committee |
| ENGINE OIL IN THE COOLING SYSTEM ON 1.9L VIN 8 & 9 ENGINES |
Engine Oil in the Cooling System On
1991-97 GM 1.9L VIN 8 & 9 Engines
AERA members have reported engine oil in the cooling system on 1991-97 GM 1.9L VIN 8 & 9 engines. Only Saturn vehicles equipped with this SOHC engine may encounter this condition. Symptoms of this condition may include engine overheating. The owner may also comment on continuously adding engine oil to the crankcase.
The source of this condition may be located in the rear of the cylinder head at the number four and five camshaft journal bores and areas. Cracks located in
this area (See Illustrations Below) of the head may allow engine oil to mix with engine coolant. These cracks may have been caused by irregularities during
manufacturing of the cylinder head. Pressure testing of the cylinder head with the camshaft installed, may not always reveal a leak. Removal of the camshaft
is necessary to successfully pressure test this cylinder head.
AERA members have successfully repaired some of the cracks in the cylinder heads. If the cracking of the cylinder head is beyond repair, Saturn recommends
replacing the cylinder head. Replacement of the head has been covered under the normal Saturn warranty conditions.
Year Model Head Gasket Head Part Number
Part Number
1991-94 21008324 21008232
1995 21007332 21007138
1996-97 21007332 21006837
The AERA Technical Committee |
| CYLINDER BLOCK CAUTIONS FOR 1.9L ENGINES |
Cylinder Block Cautions For
1990-2000 GM 1.9L VIN 7, 8 &M 9 Engines
The AERA Technical Committee offers the following cylinder block cautions for 1990-2000 GM 1.9L VIN 7, 8 & 9 engines. These engines are used in Saturn vehicles and the information applies to both single and dual camshaft designs.
Cylinder block inspection:
Use extreme care and do not scratch any of the machined surfaces. It is recommended to use a plastic gasket scraper while cleaning machined surfaces of the aluminum block.
When cleaning the cylinder block, do not heat the block above 120°F (44°C) as additional heat may allow cylinder sleeve movement the cylinder head is removed.
Remove all traces of RTV sealer from all blind holes including oil pan, front cover and rear seal carrier boltholes with a 3/16 (4.76MM) drill. Doing so will reduce the likelihood of the casting cracking during assembly. (See Figure 1)
Clean the bolt holes and gasket surfaces with a chlorinated solvent such as carburetor spray clean, brake clean, or alcohol. Do not clean block with Petroleum based liquids, as they will leave a film unto which RTV sealer will not stick. (See Figure 2)
Check top of block for allowable flatness: (See Figure 3)
Width .0009 (0.24mm) to a max of .0020 (.050mm).
Length .0031 (0.80mm) to a max of .0040 (.100mm)
Liner Height should be flush +/- .0005 (.013mm).
Inspect cylinder liners for size:
Liner number?s 1,2 and 3 standard diameter is 3.2280-3.2287 (81.99-82.01mm) and the maximum standard diameter is 3.2297 (82.035mm).
Liner number 4 standard diameter is 3.2283-3.229 and the max standard diameter is 3.2301 (82.045mm).
Standard out of round and taper all .0004 (.010mm) max.
Service limit .0020 (.050mm) max.
Inspect cylinder liners for surface finish:
Deglazing can be done with a flex hone if the liners are the correct size and a 45° crosshatch is required as shown in Figure 4.
If oil consumption has occurred, honing is required with 380-450 grit stones.
If the cylinder bores require boring to an oversize diameter, remember the number 4 cylinder liner is .0004 (.010 mm) larger than the other three liners.
The AERA Technical Committee |
| OIL CONSUMPTION |
Oil Consumption On
1990-92 GM 1.9L Saturn Engines
AERA members have reported instances of oil consumption on 1990-92 GM 1.9L Saturn engines. GM considers excessive oil consumption on this engine to be more than one quart of oil (.95 liter) per 3,000 miles (4827 km). This condition may result from oil passing by worn valve stem seals into the combustion process.
If cylinder compression values are within the normal range of 185-205 psi (1,276-1,344 kPa) and valves are not damaged, installing new seals Part #21006516 should solve this problem. It is also possible to install new valve seals without removing the cylinder head from the block with the proper tools.
If cylinder compression values are lower than normal, performing a cylinder leakdown test may indicate further engine disassembly is required.
Another consideration for oil consumption is a problem with the positive crankcase ventilation system, which is described in AERA Technical Bulletin TB-791.
The AERA Technical Committee |
