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Engine Squeak

I have a 1999 Dodge Ram 1500 V6 that has been squeaking for a long time now, slowly getting louder and more obnoxious. The belt and belt tensioner were bad so I replaced them, but the squeak was still there. Then I replaced the tensioner pulley, followed by the alternator, but it still squeaks. If the belt is removed and the engine run, there is no squeak. Its very hard to localize where it is coming from - as best I could tell it was coming from the tensioner or the alternator (they are next to each other), but with both of them replaced and nothing else nearby I am at a loss. Looking through some other discussion boards seems like another common problem is the fan clutch. Mine actually went bad 4-5 years ago so I replaced it back then, but this squeak is different than what it was doing back then, so I’m hesitant to replace that again.

Any ideas?

The squeak might be coming from the water pump bushing. Water pump bushings will make that type of noise just before the water pump seizes up.

Tester

@climbhigh more possibilities are the idler pulley and the harmonic balancer.
Fan clutches typically don’t make a squeaking noise.
Remove that belt and spin the idler pulley. If in doubt, replace it.

I finally took it to my mechanic this week, which didn’t do me any good. His only explanation was that the belt was too big. He said the belt was technically the right size, but he thought it was too big, which caused the tensioner to essentially extend all the way out. By going beyond its intended length, the tensioner was rubbing against something causing the squeak. He said he tried the next size belt smaller but it was too small to fit. He also tried a new tensioner but that didn’t fix the problem either.

Fortunately he didn’t charge me anything for this “consult.” But when I got home I examined the tensioner and couldn’t find any place where it might be rubbing against something. It has free range of motion, and if you watch it while the engine runs it barely moves, if at all, making it hard to believe that such subtle movements could make such a loud noise.

I asked him about some of these other possibilities - the fan clutch, the water pump bushings, but he was confident that neither of them were the culprits.

Not really sure what to do at this point…I hate to just keep throwing money at this thing…

Thanks for all the input!

Have You Tried Locating The Sound By Listening Up Close ?

Some sounds are easier to isolate using either an automotive stethoscope (15 bucks at Auto Parts or Sears) with two ear-pieces or a length of hose (discarded hose - freebee) placed against one ear. I’d use both.

Carefully probe different componets and areas of the engine compartment while the noise is present until something stands out as the culprit. Obviously, you can’t touch moving parts with your probe and you must be careful not to have anything “grab” it. Don’t have anything loose on you that could also be caught in there.

CSA

A 3/4 inch rubber hosed used like a stethoscope (watch out for moving parts) can be a tool to locate the source of the noise.

@climbhigh I’d think twice about taking it back to your mechanic.

" . . . the belt was too big. He said the belt was technically the right size, but he thought it was too big . . ."

Putting on a smaller belt is doing you NO favors. The bearings in your accessories may quickly wear out. Unless there is some technical service bulletin or other document instructing the mechanic to put on a non standard length belt, you put on the correct belt.
Period
End of discussion

Perhaps he will next say your brake pads are too big . . .