08-12-07, 12:08 PM
Hello again, I have been hearing a rattling sound comming from the engine for the past couple weeks. A friend and my mechanic told me that it sounds like it's comming from the fan bearing but I'm not sure. Can anyone tell me what a bad fan clutch bearing can sound like and what are some symptoms please?? 1992 Broougham 5.7 111000miles.
Thank you again
08-12-07, 01:10 PM
just grab one of the fan blades( with the engine off!!) and try to wiggle it back and forth, If it moves the bearings are bad.
08-12-07, 06:47 PM
mortis08, I tried that already..very little play. can it still make noise wothout it havng much play? I want to know examples or close toos of what a bad fan clutch bearing sounds like
The rattle can also be from the water pump or even a pulley that is close by, all are in the front of the engine. Try to use a mechanics stethoscope or a piece of rubber hose to listen to each component while the engine is running. BE CAREFUL - don't get wound up in a belt!
08-14-07, 08:22 AM
Mud, thank you for the reply. My water pump is actually going....It leaks bit by bit from the bottom weep hole of the pump..Can this be it?
I would not be surprised at all if the noise was the WP bearing. Remember that the WP shaft has the weight of the fan clutch/fan/pulley out on the end of it plus the dynamics of the spinning belt. You may not hear anything trying to spin it by hand, but it can certainly be bad and noisy when under load. Coolant leaking from the seal (as you've spotted from the weep hole) is also coolant that is wiping out the bearing as well.
I would suggest replacing the WP as you obviously need to, then see if the noise remains. While you are at it, it may a good time to replace any coolant hoses that are getting a little soft around the clamps or are old.
A note on fan clutches - I have seen many that are still somewhat stiff to turn, but are not 100%. This comes into play at hot idle, especially in summer when you need lots of airflow over the radiator and the a/c condenser. You will find engine and a/c vent temps creep up while sitting in traffic. I can always hear the "roar" of a new fan clutch doing its job when replacing what I thought was one still in reasonable shape. The roar is the sound of the full air flow pulled in by the fan. Anyway, I tend to replace them at about 100K miles or so just to ensure that the engine and a/c systems are getting max air flow.
The Ape Man
08-14-07, 06:57 PM
If the water pump weeps it's time to replace it. Bad fan clutches usually seize pretty quickly and cause nasty engine speed sensitive vibrations.
08-15-07, 12:26 AM
Another note: it's very important to have enough airflow over the a/c condenser at idle. If you don't you will subject your a/c compressor to high pressures, and as my mom found out with her truck, cause it to seize.
Now we know to check the fan clutch every couple years. I just replaced mine on my DeVille.
09-01-07, 01:59 AM
follow up: went to my mechanic today.and the rattle was actullty the alternator pully bearing AND the water pump bearing....so got both changed.along with fresh oil.....new alternator = car har more prep. I can swear the front passenger window rises faster now.....