Nissan Engines make 2 Noises:
gateway wrote:Have a 2010 Rogue, bought brand new, and rattles for 2 seconds on startup. Has done it since brand new. Dealer cannot reproduce condition - and was also told that this is normal. The noise is a distinct metal to metal contact. Souns like a collapsed hydraulic lifter; but I know there are none in this engine. Has anyone managed to get a video of this? I try to catch mine every morning but it only happens when I don't have my camera with me. I am extremely unhappy with the nissan brand.
the 1-2second rattle upon start-up -&- the tapping you hear for about 1-5minutes upon initial warmup when its cold outside. i will describe both noises for you:
Initial Start-up (1-2seconds) Rattle:
This is Totally Normal. Nissan engines use oil as the hydraulic pressure to adjust the cam chain tensioner. it takes a second or 2 in the initial start up to build the oil pressure up in order to bring the chain tension under the correct tension to prevent the chain slap that you are hearing. This also happens on Yamaha engines, and many other engines that use this type of timing chain system.
If you dont like timing chains, feel free to go buy a volkswagon or acura/honda or similar car that uses flimsy rubber timing belts and costs over $1,000 every 50,000miles to replace. that random rattle is the pay-off for the expensive out-dated timing belts. more and more engines use timing chains now a days. these tensioning systems are too are a wear item- but i dont see this going before 150,000miles IF PROPER OIL CHANGES WERE SCHEDULED. check your oil level to make sure its not low(thus the reason for chatter to begin with) and make sure its not getting to crazy. otherwise chain chatter upon start-up is normal.
wrong engine, i know- but still a nissan nonetheless.
please see the TENSION ARM and see how it places tension on the chain WHICH IS TURNING THE IDLER SPROCKET(upper one).
Warm-Up 1-5 Minutes Tapping (commonly refereed to a knocking or slapping type of noise):
This kinda sounds like banging a spoon on a coconut = this is called 'piston slap'. Some mechanics see this as sign of a worn engine, but in our case of the Rogue it's due to the engine design and not wear/tear. This is common also on many engines if this is how the engine was designed- which in our case, our engine was designed for expanding - so its normal. (but this also happens when the engine is worn as parts reduce in size, and cause constant piston slap) how do you know the difference? ours goes away once the engine is warm = it was designed this way and is normal. LET ME EXPLAIN.
As Kerrton stated; our engine(QR25DE) is a very long stroke, 4 cyl engine. That combined with the short piston connecting rod design produces the piston slap you are hearing. The piston rings sit higher on the piston to further seal off any carbons inside the combustion chamber to further reduce lost power. After the engine warms up, the piston expands inside its cylinder and creates a tighter "seal" so to say and no longer clicks its skirt against the cylinder wall.
If the clicking you hear would NEVER go away - even after reaching operating temps = then you have a worn piston. but since ours goes away after operating temps are achieved; its a normal design. THIS IS WHY I PREACH TO NOT DRIVE THE CAR FOR AT LEAST 3-5MINS WHEN BELOW 40DEGREES.(earth friendly hippies dont want you to idle, but i dont care. if the seal is not achieved, combustion gases sneak past the rings/piston and into my oil)