I worked this week on a 1989 240 wagon (250K miles) w/ 3 problems: 1) a belt squeal at start up - and sometimes w/ the headlights on; 2) a rumbling-vibration under the hood - worst at idle; 3) a tiny coolant drip from the water-pump (WP) area. I guessed: bad alt bushings + (maybe) bad/ glazed alt belts; and a water-pump leaking at the seal from the cocked alternator.

Turned out that the leak-squeal were not related - the WP leak was at the donut.

re the alternator:

1) Both alt bushings were bad - the rear worse. Yes, commonplace.

1a. When I looked at the long lower bolt I noticed that the threads were stripped < 1" from the end and the nut couldn't be tightened. Looking through my spare bolts, 2/5 have the same problem (unnoticed before).

I infer from this that when the bolt is loose (improper tightening/ no lock-nut/ worn bushing) the metal inner sleeve rides on the threaded area of the bolt. Easy fix - add 1-2 washers under the bolt head.

1b. I also noticed that the lower alternator pivot was shorter than a factory unit by ~ 3/16" (cheap aftermarket job?). The unit had been that far forward - which was visible looking down at it. Same easy fix - 2 washers for shims.

1c. I replaced the alt bushings w/ used AC bushings from stock. These don't seem to wear as much.

2) the vibration is gone, I believe via the bushing replacement and shimming.


I've seen several 240s with loose lower alternator bolts; some with missing nuts; a couple with missing bolts - not drivable, usually "there was a bang and a screech ... all the dash lights came on". I infer here that someone lost the airplane nut during an alternator/ bushing replacement and used a regular nut.

On a frail car that's been sent somewhere with far far away, I often double-nut.
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240s: 2 drivers and some parts cars