Cold start clicking; pulley?

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2000 Durango, 4.7L, 122k. I'm getting a click from the front of the engine compartment on cold starts. Under 30 F only. Installed a rebuilt AC compressor over the summer, but I don't think that's the culprit. Seems to be one of the pulleys the serpentine belt uses.

First time having an issue like this. Goes away with some heat/time. Doesn't seem like a huge deal at this point, but I always feel better when my car starts and it doesn't make unusual noises.

What am I hearing?
 
What you're hearing is your hydraulic valve lifters starving for oil at start up. Either your oil filter is too restrictive, or your oil isn't flowing quick enough at those low temperatures.
 
Originally Posted By: Merkava_4
What you're hearing is your hydraulic valve lifters starving for oil at start up. Either your oil filter is too restrictive, or your oil isn't flowing quick enough at those low temperatures.


You do realize that with a POSITIVE DISPLACEMENT pump, all the oil from the oil pump is going through that filter, no matter what, right? The only exception would be if the filter was experiencing too great of differential pressure and some oil was bled off through the by-pass valve- and those times are rare. Jim Allen did a lot of testing and data logging to support/prove this.

Besides ticking lifters, another possibility is a leaking exhaust manifold. The 4.7's liked to break bolts/studs and tick a bit when cold.

If you're confident that it's in the accessory drive, then remove the belt and restart it. If the noise goes away, give each item driven a spin and a wiggle. You may find a growling bearing that way.
 
Thanks. But it's not IN the engine. It's in front of the engine and behind the radiator. I'm pretty sure it's a pulley/tensioner.
 
Do you have an engine stethoscope? Put it on the bolt that holds the pulley wheels on.
 
Originally Posted By: Michael_P
Do you have an engine stethoscope? Put it on the bolt that holds the pulley wheels on.


Thats the only way to pinpoint the noise. If you don't have one and can't borrow one, a length of garden hose does a fine job. Hold one end to your ear and then carefully hunt around for the noise.
 
My bet its a pulley . Thought I had a lifter going bad on the bird one time turned out to be a bad pulley.
 
Is it rhythmic, corresponding with engine RPM? Or a single or occasional click? If your defroster is on the AC compressor will be running so there would be that clutch click. Exhaust metals can click or "tink" when warming up (or cooling down).
 
If changing RPMs doesn't change the noise, it is unlikely to be related to the belt, or anything turning with the belt. How often do you hear the "click" ie. Many or several times a second, once a second, every 15-20 seconds, once a minute etc. It might be nothing to worry about.
 
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