Engine fan hitting something noises??

clarkent1

A couple of days ago I started hearing loud noises that sound like the fan is hitting something when I'm at idle or slowing down for a stop sign, but the noise goes away to normal at speed.

I cannot see the fan hitting anything, all seems tight and even with a friend looking, we cannot tell where the noise is coming from looking at the engine.

I'm afraid it could be some bearing in one of the pulleys or engine, but how come it goes away at speed and the car runs normal. Any ideas?

tidester

Could it be the fan clutch or water pump?

tidester, host
SUVs and Smart Shopper

clarkent1

Somebody said that maybe the timing chain adjustor is loose and maybe the chain is loose and it tightens itself at speed. Does this sound like something possible.

What could make loud clacking noises at idle and correct itself at speed?

tidester

At higher speeds the centrifugal force on the chain will keep the tension higher. The noise at lower speeds may be the result of a little slack in the chain which is essentially nonexistent with high tension.

tidester, host
SUVs and Smart Shopper

clarkent1

I wonder if I could I still drive the car lightly... Is this something I can fix or do I need a specialized mechanic... ?

tidester

I can't advise you on that but I would consult with a mechanic or visit the dealer.

tidester, host
SUVs and Smart Shopper

mglossip

after reading this, i went out and felt my chain and it did indeed feel a little loose. maybe theyre right.

mglossip

its been a while since you posted on your noise problem. i dont know if youve gotten the full blunt of the problem yet. well in case you didnt.....i have a 2000 3.5 liter and i had the same problem. i now broke a rod and have to hopefully just rebuild my engine (that is if the rod didnt screw up my cylandar) ive done alot of research on this problem and the our engines just suck.....get a rebuild kit and dont drive anywhere if you have the same problem as me..our rings only have 4 small oil drain holes and they get blocked really easy thus burning oil really fast, the way way of knowing this in time is with an oil pressure gauge that our vehicles dont come with.
take it easy

whitall

Our 2004 Tahoe has always had some knocking noise in the dash, if course it wouldn't perform on demand while it was under warranty. Now it is more persistent. It sounds like knocking, it happen mainly when the heat is on and the controls are set all the way to the top of the red. When we back it down 2-3 notches the noise usually stops. I do think it does it with the a/c too, though haven't tried to isolate at what temp contol it does it. I think maybe it has to do with the blower motor. In my Taurus that was an easy do-it-yourself. Any thoughts on what it is? ( I think I hear it best when my ear is to a vent--but noises are so hard to tell where they are coming from...)

1999trooper

i was wondering how your rebuild went. i have a 1999 3.5 that i suspect just lost a rod bearing, or there is a monkey trapped inside the motor trying to break out with a ball-ping hammer, either way i may have to rebuild. Did you buy a kit? which brand? did you consider a swap with a different gm motor.