Operation CHARM: Car repair manuals for everyone.
Home >> Audi >> 1998 >> A8 Sedan (4D2) V8-3.7L (AEW) >> Repair and Diagnosis >> Powertrain Management >> Tune-up and Engine Performance Checks >> Compression Check >> Testing and Inspection
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Compression Check: Testing and Inspection

Requirements
- Minimum engine oil temperature 30°C (86°F)
- Throttle valve fully opened during cranking

Checking





1. Remove fuse 1 from fuse panel -4- at right A-pillar.
- Reinstall fuse after completing compression test.
2. Check compression with compression pressure recorder tools No. VAG 1381 and adapter VAG 1381/5, or equivalents.

NOTE: Refer to the operating instructions for use of the compression tester.

3. Crank engine with starter, until no further pressure increase is indicated on tester.
Compression pressure specifications:
New: 10-15 bar (145-220 psi).
Wear limit: 7.5 bar (110 psi).
Permissible difference between all cylinders:
Maximum: 3 bar (44 psi).
pro multis · About Operation CHARM