knock on startup

Daishi

It is about 20-22 degrees outside this morning started the car up while i was at home everything ran fine the clutch was a little slow to react since it was so cold out hard to explain but i babied the car on the way to work. After I got to work and shut the car off.. waited a few seconds then started it back up again dont ask me why i just felt like doing it but this time when starting it made a knocking noise its hard to explain. I started and turned the car off a couple more times and it did it like twice more it happens as soon as the car turns over. Waited a few minutes and started the car again and no noise.. not sure what it was. Any suggestions? I know cars can act funky in such cold weather maybe it was the transmission making some kind of noise im not sure.. BTW i checked the oil and its full.. this is the first time its ever happend and this is the coldest day its ever been so far this winter.

spearfish25

Cars Do strange things when it's cold. Mine has been making all kinds of new, creepy sounds since the temps drop and the salt trucks started rolling. Do yours a favor and don't keep starting it in the super cold weather...causes lots of wear as this is when the oil flow is the worst (oil=sludge at 20F)

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2013 Cadillac V-Wagon, RIP Z

kannibul

+1, if you're not going to drive it until it get fully up to temp, don't start it.

High compression + cold engine can also = knock
Lack of oil getting to all the important places can also sound like knock...


My truck is a great example, first 1-2 seconds of start up when it's cold out = rattling engine, especially the valvetrain - sounds similar to cylinder knock. Once the oil hits it with pressure it goes away. Not a whole lot I can do about it either...just hope there's enough residual oil stuck to the parts...

Daishi

The car started fine in the cold weather.. its after its fully warmed up where i have the issue. I work at a vw dealer had a few of the techs listen to the noise its making and they told me it sounds like a bad starter i can replicate the issue everytime but its only after the car is driven and fully warmed up where i turn the car off then turn it back on. It basically sounds like the starter is skipping teeth on the flywheel.

j.arnaldo

Only 93-octane goes into your gas tank? Maybe hooking her up at a Diagnostics Center may reveal some ECU glitch. I'm no mechanic, but it sounds worrisome enough to check it out. Good luck!

chuckd05

my car def didnt like the 24 degree weather today either... it kept my idle around 2k until my oil was 180 degrees... it was kinda strange it slowly raised the idle to 2k when i was at a stop sign or light... i warmed the car up for about 5 minutes too.. but the oil took forever to get to 180 all though the digital temp gauge showed it was warm.. but until the oil temp hit 180 it was raising my idle..

i kinda feel bad for the car driving it in such cold weather.. the bridgestones certainly dont like the cold either.. i need a beater!

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09 370Z 6M PW - FBO Best 1/4 mile = 12.926 @ 109 SOLD -- 08 BMW 135i - FBO 12.1@120mph SOLD -- white 09 e92 335 Coupe Mtech - 11.9 @ 119 :-)

Daishi

yea I only put in 93 octane. car runs great otherwise.. I just dropped off my car at nissan we will see what they have to say.

needr6parts

Anyone noticing a noise when the clutch is pushed in.I can feel what seems to be a little noise like the throwout bearing when the clutch pedal is pushed in and it has a little vibration through the pedal.I had someone hold it in while i listened under the hood but could not hear anything but you can feel it through the pedal.My car has almost 11,000 miles on it and was wondering if anyone else feels this before i take it in?

Rps13.jw

If your referrin to the loud ticking sound(sounds like knocking) Its normal. The oil need to recirculate throught the motor after its been sitting. The noise is coming from the lifters. When they are empty of oil they make a loud ticking sound.

Daishi

nissan replaced the starter on my car but its still making the grinding sound. but ive been able to reproduce the issue only when its extremely cold out. below freezing. and it only happens right after i drive the car. if the car sits it doesnt happen. and now my intelligent key warning light is on lol. how many stupid problems am i gonna have with this car? hah. maybe thats cold related too lol. we will see what happens. supposed to be getting warmer the next couple days.

sminky63

Mine did the same thing...9 degree tempurature outside. Even with a warm engine, it made this disturding knocking sound on start up. Now that the temp outside is higher, the car hasn't done it again. I think (and hope) that it's just an extreme cold temp thing.

I think that the 370Z just doesn't like really cold weather.

Daishi

agreed the car hates the cold weather.. now my intelligent key warning light comes on occasionally and my steering wheel isnt locking. hopefully its just cuz its really cold out.. id notice in the morning when its 20 degrees out id go to start the car and the mechanism that unlocks the wheel would take longer than normal to unlock.

spearfish25

Nissan probably screwed up your car when they changed the starter.

Rereading your OP, I have noticed the same thing a couple times with my car. If I drive home from work (engine warm), turn off the engine, and then immediately restart it (eg if I don't like how far I've pulled into a space and need to move the car), there is a <1sec knock when it restarts.

My guess is the A/F ratio is 'off' with such a quick restart and the car/ECU quickly fixes the issue. I don't know if it's residual fuel, time needed for the injectors to reset and start working, etc.

I NEVER get a knock when I cold start the car or wait a few minutes before restarting.

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2013 Cadillac V-Wagon, RIP Z

hsdw

Hi there,

I recently bought a 370Z with the 7 speed auto. It is cold here where I'm from.
-6F. Car has about 2100 miles and I noticed the same knocking noise on start up after the car has been warmed up. I would restart the car within a minute and get this knocking sound sort of like a diesel engine for about 1 second.

Any update on this situation? Is this a problem and it is NOT normal?

Thanks.

370zFORme!!

Ive had this problem since day one. Not even weather related for me. Most times it just happens when the car is warmed up, turned off, then back on. Happens on hot days, happens on cold days. Most chalk it up to this car just having noisy valve-train.

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87' Honda Civic Hatchback: Kaput @ 288,000 miles, 90' Toyota Celica: Kaput @ 175,000 miles, 93' Mitsubishi 3000GT VR4: Kaput @ 138,000 miles, 06' Scion Tc: Traded in @ 64,000 miles, 10' Nissan 370z: Traded in @ 25,000 miles, 12' Subaru Impreza Sti: Current.