Some pre-2005 Ford Expedition and Lincoln Navigator sport-utility vehicles may produce a humming-type sound from the right corner of the engine compartment.
Ford said a noisy air suspension pump is the likely source of the irritation. A new air suspension pump noise suppression kit, part #4L1Z-5Z205-AA, is now available to alleviate the condition. Included in the kit are a newly designed pump mounting bracket, noise-suppressing isolators and complete installation instructions.
The kit helps prevent metal-to-metal contact between the pump and mounting bracket and the inner fender skirt and radiator support—all contributors to the noise complaint.
Drivers of 1999 Passport models may come into your store complaining of a constant, humming-type sound from the engine bay.
If you lift the hood you're likely to find that the anti-lock braking system (ABS) pump motor is running continuously. Honda said the most likely source of the problem is a burnt ABS coil integrated module.
Replacing the module (part #8-97202-408-0, H/C 5904016 for two-wheel-drive models; part #8-97214-704-0, H/C 6104947 for four-wheel-drive models) and possibly the complete hydraulic valve block is the permanent fix.
To find out whether one or both parts need replacing, locate the plastic gasket between the ABS pump motor and hydraulic valve block, as shown in the illustration (far left).
If the gasket looks melted—especially in the area where the wires come out of the pump—replace both the valve block and coil module. If the gasket looks OK, replace just the module.
Owners of 1995-98 Maxima models built before Feb. 4, 1998, may complain of a buzzing or rattling sound from the front suspension.
The noise occurs most frequently on rough road surfaces, Nissan reported, and is most likely the result of the coil spring windings contacting each other during suspension travel. Installing new-design front coil springs (part #54010-4L809, manual transmissions; part #54010-4L808, auto transmissions) and lower spring seats, part #54034-31U15 (two included) should eradicate the noise.
When installing the new springs, make sure the paint marks on the coils are facing up. The new springs have pre-attached upper and lower seats. Don't remove them!
Install the additional lower spring seat so that its thicker portion butts against the pre-attached rubber seat of the new spring.
“Factory Fixes” is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected]