Engine - Thumping Noise

88ford08

ENGINE - "THUMPING" NOISE - 3.8L - #1 MAIN BEARING

NOISE - "THUMPING" FROM #1 MAIN BEARING - 3.8L

Article No. 88-7-10

FORD: 1988 THUNDERBIRD

LINCOLN-MERCURY: 1988 COUGAR


ISSUE: A "thumping" noise from the engine assembly may be caused by too much clearance in the upper #1 main bearing. The noise is noticeable under the following conditions:

^ Transmission in gear and engine RPM just above idle.

^ "THUMP" is ONLY heard inside passenger compartment.

^ "THUMP" is more noticeable with the A/C on.

^ "THUMP" occurs at about half the engine speed.

ACTION: To correct this, use the following diagnostic procedure to determine if a new undersize upper #1 main bearing is required.

1. Confirm that the thumping noise exists under the above conditions.

2. Remove the air conditioner accessory drive belt.

3. If the noise is eliminated with the A/C belt removed, install a new upper #1 main bearing, (E8DZ-6333-A) that is color coded blue. Refer to the 1988 Car Shop Manual, Volume D, Section 21-15-35.

CAUTION: If the engine is raised, the EGR backpressure transducer must be removed. Use the procedure outlined in TSB 87-24-11.

PART NUMBER PART NAME CLASS

E8DZ-6333-A Main Bearing - Upper CG

OTHER APPLICABLE ARTICLES: 87-24-11
WARRANTY STATUS: Eligible Under Basic Warranty and Powertrain Warranty Coverages
OPERATION: 880710A - Inspect only
TIME: 0.3 Hr.

OPERATION: 880710B - Inspect and replace bearing
TIME: 3.1 Hrs.
DLR. CODING: Basic Part No. 6333
Condition Code: 56