Lack of Compression For
                                                       1998-2001 Audi 2.8L 5V Engines

The AERA Technical Committee offers the following information regarding lack of compression on 1998-2001 2.8L 5V Audi engines. Complaints for this condition include poor performance, hard starting or no start conditions. The cause of this condition may be carbon build-up on any of the engines thirty valves preventing it from sealing. 

Several measures are now available from Audi to resolve and help prevent reoccurrence of this condition. They include installing a hotter thermostat and performing an approved carbon cleaning process. At this time, only Wynn's X-Tend® V.I.C. Combustion Chamber Cleaner: Part No: 61510 (U.S.), Part No: 61512 (Canada) is authorized for use by Audi. 

A revised (hotter) thermostat was developed and installed in engines beginning after VIN 8DXA279411 for A4 vehicles and after VIN 4BXN116771 for A6 vehicles. The thermostat operating opening temperature increased from 87°C to 92°C. 

Engines should also be checked to verify the coolant temperature sending unit must be later than week 19 of 1998, i.e. 19/98. This will be stamped into the side of the sensor housing (arrow) as shown in Figure 1. Replace the sensor if necessary.
  Figure 1.

Note: Customers should be made aware that this type of carbon build-up may be due to fuels that do not contain a sufficient blend of detergents. Customers should be given the brochure Facts about Carbon and Fuel Quality (Literature No. W425527100) and advised to use Autobahn Gasoline Additive (ZVW 239 003), which is very effective in reducing and preventing carbon buildup, even if the fuel used does not contain a sufficient blend of detergents.

Audi also recommends installing a new set of spark plugs. Install new spark plugs Part #101000067 AA (NGK BKR6EQUPA) and a set of six 4-hole injectors, Part #078133551BA. The injector can be identified by their RED color as shown by the arrow in Figure 2.
   Figure 2. Four Hole Injector

It will also be necessary to change engine oil after carbon removal treatment and it is Important to note: DO NOT use 20W 50-engine oil - use ONLY factory-approved oil with proper viscosity.  

                                                                       The AERA Technical Committee

                                     Rear Main Crankshaft Seal Leak On
                                           Audi 2.0L, 2.2L, 2.3L Engines

AERA member shops have reported rear main oil seal leaks on the 2.0L, 2.2L, and 2.3L engines.  The engines are used in the Audi 80/90 and 100/200 cars.  

To verify that the engine oil leak is coming from the rear main seal, and not from the engine's valve cover, use florescent dye in the engine oil and a black light.

Audi has released an improved crankshaft seal, part number 068-103-051G to help correct this problem.  The new seal went into production after VIN # 44 LN026115 for the 100/200 models, and after VIN # 8A LA048000 for the 80/90 models.

Audi also advises using locking compound on the flywheel bolts to seal the crankcase.  The torque for the non-shoulder bolt is 55 lbs. ft.  The torque for the shouldered bolt is 74 lbs. ft. and Audi advises to always use new shouldered bolts.
                                                                         The AERA Technical Committee

                                        Hydraulic Valve Lifter Noise On
                                     1988-91 Audi 2.0, 2.2 & 2.3L Engines

The AERA Technical Committee has been informed of hydraulic valve lifter noise on 1988-91 Audi 2.0, 2.2 & 2.3L engines.  This noise may be heard both at engine start-up and during low engine RPM.  To reduce the possibility of undesirable lifter noise, Audi now supplies a new lifter, Part #034109309AD for all 4 & 5 cylinder engines.  

It is important to note that it may take as long as a week to purge all air from this new lifter after installation.  At the time of this publication, AERA is unaware of an aftermarket supplier of this lifter.

                                                                        The AERA Technical Committee

                           Valve Crosshead To Rocker Lever Clearance On
                              NH, NT & V-1710 Series Cummins Engines

Valve crosshead nose to rocker lever clearance on the subject engines must be checked during engine rebuild and at any time valve crossheads are replaced on engines using crossheads No. 123416 & 3000326. A minimum of .020 (.51 mm) clearance must be present as illustrated in Fig. 1, on the cylinder being checked with valves completely closed and crosshead in the upmost position. After installing rocker lever assemblies, check crosshead to rocker lever clearance as follows:

1. Turn crankshaft slowly in direction of rotation until the valves are closed on the cylinder being checked. With rocker lever held firmly against the stellite pad of the crosshead, a .020 (.51 mm) wire type feeler gauge must pass between the crosshead nose and the lower beam section of the rocker lever.

2. If the feeler gauge does not pass through:

a. Remove the rocker lever and/or crosshead and grind the nose of the crosshead or 	rocker lever beam in the area circled in Fig. 1 until enough clearance is obtained.

b. If the rocker is ground, grinding should cover the complete area illustrated in Fig. 2 in a continuous arc. Do NOT grind just the contact area.

Caution: A sharp depression in this area will cause a stress riser and eventual failure of the lever. Grind only enough material to achieve the required clearance. If grinding enters the oil passage, the rocker lever must be junked.

c. Grind sharp edges smooth.




                                                                   The AERA Technical Committee

Crankshafts Used In Industrial Applications On
GM (Chevrolet) 5.7L (350 CID) Engines

When the GM (Chevrolet) 5.7L (350 CID) industrial engine is used in some applications such as lift trucks, the only crankshaft that is applicable has the forging number 1182.  Dimension A of the rear flange is slightly smaller than that of other crankshafts used in General Motors 5.7L (350 CID) engines.

The larger flange crankshafts will not pass through the center hole of the bell housing.  This is very critical when an oil clutch system is used.

                                                                     The AERA Technical Committee

Burned Exhaust Valves, Low Power & Hard Starting On
Cummins NH & NT Engines With Jacobs Brake 25B & 30

Cummins Engine Co. reported that if the following complaints are experienced in the NH and NT engines equipped with Jacobs brakes, the slave piston clearance should be checked:

A. Exhaust valve burning

B. Low engine power when at operating temperature 

C. Engine hard to start or will not start at operating temperature

A standard slave piston adjustment of .018 +/- .001 has been established.  The .018 clearance setting is a cold setting which results in zero slave piston to crosshead clearance when the engine is at operating temperature.

Should the slave piston clearance setting be less than .018, the following conditions outlined in A, B or C above may result as well as affect breaking power.

If the slave piston clearance is greater than .018 +/- .001, the following problems may occur:

1. Engine injector train component problems
2. Injector carboning
3. Bent injector push rods
4. Worn injector adjusting screws
5. Decreased camshaft life
6. Cam follower and follower shaft failure
7. Delay in breaking action

If the above problems are experienced and the engine is equipped with a Jacobs brake, the slave piston clearance should be checked with the latest Cummins specifications.

                                                                     The AERA Technical Committee

                                      New Cylinder Liner O-Ring Seals On
                                      Cummins NH/NT 6 Cylinder Engines

Cummins Engine Company has released new O-ring seals for the cylinder liners in NH/NT 6 cylinder engines.  The new seals are made of an EP material and have a smaller diameter cross-section.

The new seal replaces both the old center seal #3008998 and the old lower seal #183049.  The new seal carries Cummins part #3032874 and is black in color with one blue dot.

The new O-ring seals are not to be intermixed with the former seals on the same liner.  Cylinder liner deformation will result.  You can use the former seals and new seals in the same engine as long as they are used in the correct combinations on each liner.  The illustration below shows the correct combinations.

                                                                       The AERA Technical Committee

                                               Oil in Cooling System on
                                         VW 1.5L & 1.6L Diesel Engines

AERA members have reported instances of engine oil in the cooling system on VW 1.5L diesel engines.  According to AERA sources, the problem is related to a crack in the cylinder head bolt hole located near the oil gallery feeding the cylinder head.

The oil feed gallery in the block is located on one side of the center head bolt hole and a coolant jacket is on the opposite side of the bolt hole.  Pressurized engine oil is diverted through a slot in the head gasket and is feed up the side of the head bolt to the cylinder head.  The oil also follows the bolt back down to the bottom of the bolt hole.  Should the crack in the head bolt hole extend to the coolant jacket, oil can mix with engine coolant.

This problem is generally found on engines equipped with 11mm head bolt holes.  Later design engines utilize 12mm head bolts and do not exhibit this defect.  At the time of this writing no successful repair procedure is available.

                                                                       The AERA Technical Committee