Audi Engine >> LACK OF COMPRESSION OF AUDI 2.8L ENGINES

Audi Engine >> LACK OF COMPRESSION OF AUDI 2.8L ENGINES

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

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