Cold weather "click"

Ok so last year, when it was cooler, I changed out my radiator and serpentine belt on my 1997 xk8. When I started the car it started a rhythmic “click,click,click” sound from the front right side of the engine bay. Kinda reminds you of a stuck blend door trying to close. It goes away in a within a minute, and once the weather got warm, it never happened again. Until now. It started getting cold again and shure enough, my clicking is back! Exactly like before! Is there some kind of electric motor actuated coolant flap that could be causing this? I can’t see anything at all when looking around.

Since the problem started right after you changed the radiator and belt, start from there. Ask yourself, what did I touch and what could have changed?

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Does the click speed up with engine speed or road speed?

It usually stops by the time I drive off as I let it idle for a minute or so. I haven’t tried reving it at all when it’s doing it. I’ll have to try that this morning. I’m sure it’ll do it seeing as how it’s 28deg out there this morning. Brrrr

Ok so yes, it increases with engine rpm. Part of me is wondering about the serpentine belt tensioner. I’m going to pull the belt in the morning and see if it goes away. Then I guess I’ll start looking around if that stops the noise

So I pulled my serpentine belt yesterday and started the car. No clicking. So I spun and wiggled all of my pulleys and they felt fine, so I thought I’d go ahead and pull my tensioner anyway and swap it with the one off of my spare engine. However, after looking at them, I found that the spare engine tensioner has the plastic pulley and my original has a metal one. I noticed that the part number was the same except for the one with the plastic pulley had a last letter in the part number that was 2 letters sooner than the metal one. I’m guessing the metal one is the more recent “update”. I messed with my old one a little and decided that it didn’t feel bad at all, and I’d prefer a metal pulley over the plastic one. I also figured it wasn’t that hard to swap out again if I was still getting the clicking. I also shot some silicone spray in the spring just to give it a little love lol. I put everything back together and started the car and no clicking at all! I guess we’ll see.

Welp i guess I spoke too soon. Smh. Went out this morning and the click is back. Oh well i guess ill plan on trying to buy new pulleys and a tensioner.

Do you have a stethoscope? Could save you money and parts.

I do have one, ill have to give it a try. Always a little leary about putting the probe near a spinning serpentine belt though. Lol

Ok so yay! I popped the bonnet today and started it up and looked around. Sure enough the tensioner was pulling back and forth every second or so and slapping back in place! I decided to just try swapping twnsioners with the one from my spare engine and yeeha no more click! It see.s nice and smooth! I may still order a new one with a metal pulley, but at least now i know for certain what it was! Yay!

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Great. Thanks for getting back to everyone. Adds to our collective knowledge.

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Well crap. Went out this morning and sure enough the one from my spare engine is doing it now, although not for as long. I just ordered a brand new one, i guess we’ll see if it completely takes care of it. If not, i wonder if one of my other pulleys or powersteering pump or a/c compressor could be hanging up and causing it to pull then release. I guess we’ll see

I realized I never updated this! I replaced the tensioner with a brand new one and it still made the noise. I then ordered another serpentine belt, and its been quiet ever since! The only thing I can think is that the other belt, when cold, kept its shape from one of the pulleys, until it went around a few times. Weird, but fixed!

Makes a lot of sense, thanks.
You don’t need to let it idle for a minute by the way, ten seconds should do it and you really want it to warm up under some load. Idling to temperature just means a very rich mixture for longer and driving away is not only recommended but it also causes no harm.

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Letting the car idle to warm up is wrong and leads to oil dilution with gas. What we should do is opposite to what we learned as kids. Start up and drive off is the new rule.

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I just start and wait for the idle to drop then go. Its usually only a few seconds