For the last few days and occasionally in the past, I've noticed a strange sound right after starting the engine from cold. About one second after the engine starts, there is a quick and rather loud "ratcheting" type sound that seems to come from right under the cab of the truck. Best way to describe it would be the sound you get from a ratchet lever on a tie down if you flip it quickly. Sounds like a gear trying to mesh or something. It only lasts for about one second and seems to only occur if the truck has been sitting overnight.
Anyone else notice this? It may be normal, but I'm not sure.
I have this too. I dont drive my truck that often so it sits in my garage for a while; when I start it after it has been sitting I especially notice it.
Could it be the timing chain? I sure hope it is not dry cyclinder walls or something like that.
Thanks for the replies guys. Good thought on the heat shield fla_guy. However, it's not a rattly/loose kind of sound if you know what I mean. It sounds like the teeth of moving gears engaging momentarily.
The truck is functioning fine though. I may ask the dealer next time I'm in if they know what it is. I'm more curious than worried. I like knowing what all these sounds are.
It's the ABS self check, I notice it more as the weather gets cooler too...check the manual if you have a hard time believing me. The ratchet sound is each of the ABS cylinders firing/checking in succession. Should be coming from the driver's side, right against the fire wall, where the ABS unit is located. Usually will only happen if the truck has been shut down and is completely cooled off.
Another sound that happens just about the same speed as the doors auto lock, is the VSC self check...makes a clunk/clank...most don't notice it cause the doors locking is louder. Sound comes from the passenger's side, towards the back of the cab. Happens when the transmission is cool. You can feel it vibrate a little. Again, it's in the manual.
One more odd one happens a couple hours after the truck is shut off, that's the EVAP check. Makes sort of a whirring sound...you guessed it, in the manual.
Hope that helps ease your mind.
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It's the ABS self check, I notice it more as the weather gets cooler too...check the manual if you have a hard time believing me. The ratchet sound is each of the ABS cylinders firing/checking in succession. Should be coming from the driver's side, right against the fire wall, where the ABS unit is located. Usually will only happen if the truck has been shut down and is completely cooled off.
Another sound that happens just about the same speed as the doors auto lock, is the VSC self check...makes a clunk/clank...most don't notice it cause the doors locking is louder. Sound comes from the passenger's side, towards the back of the cab. Happens when the transmission is cool. You can feel it vibrate a little. Again, it's in the manual.
One more odd one happens a couple hours after the truck is shut off, that's the EVAP check. Makes sort of a whirring sound...you guessed it, in the manual.
Hope that helps ease your mind.
Thanks, yes that info is helpful. I'm aware of the check that occurs when the doors lock and evap system check. But I think you nailed it on the head with the ABS firing in succession. The sound indeed seems to come from the firewall/driver side area.
Great info.
I also just read elsewhere that it might be the AC compressor kicking in. I'll have to pay attention if I left the HVAC in defrost mode thus activating the compressor on startup.
I second the opinion on the ABS self test. You can actually hear the brake caliper pistons clank around from the test when the ABS unit pulses the solenoids - really freaked me out when I heard it the first time! The longer the truck sits, the more likely it will occur, because the unit stores residual hydraulic pressure between every time the truck is driven. If it doesn't have any pressure to work with upon startup, it pumps brake fluid itself to obtain pressure for the self test.
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I second the opinion on the ABS self test. You can actually hear the brake caliper pistons clank around from the test when the ABS unit pulses the solenoids - really freaked me out when I heard it the first time! The longer the truck sits, the more likely it will occur, because the unit stores residual hydraulic pressure between every time the truck is driven. If it doesn't have any pressure to work with upon startup, it pumps brake fluid itself to obtain pressure for the self test.
Right on, that would explain why mine does it so loud; I dont drive it that much, there are long intervals between each time I get it out.
Ratcheting sound on starting cold engine?
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