Weird issue that started last winter, when it is below 32 F outside and i start up the car it makes a terrible metal clanking sound. Like somebody is under the vehicle clanking a screwdriver around under there but it only last for about 10 seconds or so then stops. It only does it when its 32 F or under. if its in the 40's or so nothing perfectly quiet, so it started last winter towards the end and it went all spring and summer and fall no noise whatsoever. Now its winter again and the noise is back. Its hard to narrow down where it is coming from because it echos, but general area is exhaust manifold and transmission case under the car. Any ideas? Car is a 2010 murano with 170,000 miles on it.
Metal clacking noise coming from under the car when its cold
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Sometimes a noise like that is caused by a loose exhaust heat shield or some pebbles rattling behind it. My '03 had a noise on startup similar to yours, it was just a pebble caught behind the heat shield... The noise goes away when the exhaust heats up and expands.
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Almost certainly you need to replace the timing chain and tensioners. Or sell the vehicle.
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2013 MO with the same issue, I've tried to track it down. I've replaced all pulleys (tensioner, idlers) all accessories (air con, alternator, power steering) thinking it was the tensioner "clacking" from some drag on the unit in the cold weather. same issue. I've been looking into doing the timing chain set (not looking forward to it) but unless there's someone with more insight about this problem I think that will be my next step. I have an idea it may be the timing chain tension hydraulic plunger getting stuck in the cold. I'm planning to pull the oil pan to look for debris (plastic) that isn't able to go through the drain plug hole. I change the oil religiously, use only synthetic and quality oil filters. I ran some sea foam through the oil, drove for about 300 miles and dumped the oil, refilled and new filter. Wife said it was less the next morning but the day after was back. Don't want to send the chain through the case or smack valves so, I guess we'll see.
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You may want to try a multichannel microphone device to better isolate where the noise may be coming from:
Wireless:
Amazon.com: Steelman Wireless ChassisEAR Auto Diagnostic Tool Kit, Identify The Cause of Troubling Vehicle Noises, 4 Transmitters with 50-Foot Range : Automotive
Wired, less expensive:
Amazon.com: STEELMAN ChassisEAR Electronic Squeak and Rattle Finder Auto Diagnostics Tool, 6 Microphone Clamps with Leads, Over-Ear Headphones : Automotive
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I would think if it's your timing chain tensioner you would see the timing bouncing around at idle when it occurs...
Have you tried using an app like Torque Pro to monitor what's going on in the engine?
Have you tried using an app like Torque Pro to monitor what's going on in the engine?
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The tach is steady at idle but i'm still suspicious of the chain. I cannot think of anything else in the vicinity. I just use a mechanic stethoscope when trying to isolate the sound, but sometimes it stops quickly enough and once its done and has warmed, it won't do it again until its cold.
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I have a 2011 Murano with 170K miles which is doing something very similar. I haven't been able to locate the cause. Like Viking_Lander, I changed the tensioner, one of the idler pulley, and inspected the other pulleys/accessories. It doesn't seem to be engine related because rate doesn't increase with engine RPM (idle to 2500 rpm). Sound goes away in less than a minute and only happens when its cold outside and been sitting for a few days.
Any update or root cause on this issue?
Any update or root cause on this issue?
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