Bearing noise

[tpm64]

As background, 2007, 20.5k GVWR, 21000 miles.

When heading out on our Thanksgiving trip, we were loaded average on the MH and towing a 5,000 lb toad. So we were about 25,000 combined weight. In going over a mountain, the fan clutch kicked in (it has only done this a couple of other times in 4 years). I slowed down some to reduce the load. No warning lights, no big movement of any gages. At the top, the clutch fairly quickly disengaged as expected.

After that, every time I headed up a hill, I got what I would describe as a fairly loud rough bearing noise from somewhere at the front of the engine. Going down hills, I would get it as the rpm's hit 4,000 or so with engine braking. 45 mph on flats and it completely went away. It is heat and/or RPM dependant, not load dependant. If I start quickly (higher load) there is no noise for a while.

i disconnected the toad and finished the trip. We made the 175 mile trip back home with the noise happening about 10 times. When I got over 60, the tire and other engine noise are louder than this bearing noise.

The fan clutch feels smooth, and I have not had time yet to disconnect the serpentine belt to check other parts. No leaks from the water pump.

Thoughts on the cause? Tests to do?

Thanks in advance.

[LVJ58]

I take it the bearing noise you're hearing is different from that of the fan noise when the fan clutch engages, correct?

Most fan clutches are heat activated, however there have been occasions with our coach when climbing a grade at high rpm's with fan clutch engaged, it would disengage, so higher rpm's may play a role in the fan clutch operation.

[tpm64]

Jim, yes - different noises. Our fan clutch is like a roar, but smooth. The bearing noise is more grating or scraping. The part that has me stumped is that it does not just get progressively worse.

I was hoping someone would say that when their clutch started to go, it sounded like mine does now.

[LVJ58]

That is interesting, it could be the fan clutch, or bearing going out on the belt tensioner pulley. Other possibilities could be AC compressor clutch dragging, or bad alternator, power steering pump, or water pump bearings.

If the grating/scraping noise varies with engine rpm then it would appear it's related to something driven by the serpentine belt.

Our coach has 74k miles and so far no noises like you describe yet.

Good luck in ferreting out the noise source, and keep us posted.


Safe Travels

[Mekanic]

I have never heard of a bearing going out in a fan clutch but that is exactly when it would make noise I suppose. You could unbolt the fan from the clutch and bolt the clutch back on so the pully is still there then run it (MAKE FOR SURE YOU WATCH THE ENGINE TEMPS SO NOT TO KILL IT) and then see if the noise comes back and normal temps. I don't think it will as I think it is the load applied to the clutch when it hget hot.
My test would rule out a water pump bearing, PS Bearing, Alt bearing,.....
I

[Jagtech]

Perhaps the water pump bearing is causing this; there's a lot more load on the water pump bearing when the fan clutch engages.

On edit: check for looseness in the pump shaft.

[cannon man]

could it be the fan blades hiting the shroud? just a thought. good luck

[tpm64]

I spent a couple of hours yesterday checking out the good suggestions I have gotten in this thread. No luck finding the problem in the driveway. No bearings seem rough, no dripping from water pump, fan clutch is smooth, no strange wear on belt.

Looks like I will have to figure out an inspection spot at the top of a hill somewhere so that I can catch the noise before it "disappears" again. Or just start replacing parts (I hate doing that).

I will keep you posted as I try more things next week.

[jimbooth25]

I had a similar issue in my 97 ford 450 dually and to make a long storie short it was the ac clutch I would make all kinds of noise and the ac still worked replaced clutch and no noise. Hope that helps but when u find the issue let us know

[tpm64]

Just to complete this thread....

It was the AC clutch bearings. Hope this helps someone else in the future.

Now, it is time to go camping.

[LVJ58]

Quote:

Originally Posted by tpm64 Just to complete this thread.... It was the AC clutch bearings. Hope this helps someone else in the future. Now, it is time to go camping.

Thanks for letting us know the fix and now enjoy your camping adventure.