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ok, I have been reading throughout the forum for a little problem I have found with my 08 SONATA i4.
I bought this car on march 10th, I drove from Marysville WA. to Eugene OR. 3 days after buying it.
When I got there the transmission started to whine a lot when first driven when cold, well transmission was replaced under warranty due to "pump failure"?
I noticed that the loaner car I recieved for tranny replacement had a knock at startup so I called and told the dealership about it, they said it was the timing chain, it was a v6, oddly it didn't sound like timing chain to me, started after fast idle and went away within about 100 feet of driving.
2 days after I got my car back it would knock after I started it up cold when it came down off fast idle, and would knock for about 100 feet of driving or so, then the knock would disappear until the next cold start. exactly like the loaner V6
well took my car in to have it looked at, got another loaner, 09 sonata I4, same **** knock, service couldn't replicate problem with my car.
went ahead and got oil change, drove car home and the next day it had the same knock at startup when cold.
Just took it back to dealership to have them look at irregular tap/knock when warm at idle, also car still has startup knock, but just not as loud.
Got an 07 sonata V6 as a loaner, it has the startup knock too. Is it just me or have any of you had this kind of knock too?
 

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I have been trying to get video of it, but My phone (LG-VU) doesnt pick it up from inside the car, and its not really clear outside either, I am still trying to get a video that is clear. Also I know that the sound is not normal, no car should make an obvious metal to metal knock at any time during operation.
 

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Oddly enough, service department called today, told me they replaced 2 pulleys and I can pick up my car, well I'm not completely stupid, I know it wasn't a pulley making the noises, I will just drive it till it stops, them let them fix it.
 

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Does the knock sound like a hollow piece of wood?Alot of cars do this when first cold, Mine does it sometimes as well. I have been told it is because the pistons in newer engines are so close to the top of the cyl head that any layer of carbon deposits will actually cause the piston tops to make a slight contact with the head. the use of a good fuel injector cleaner like Regane or Techron will usually eliminate this problem. Try that first as it worked on mine. I understand they have a name for it, called CCDI (Combustion Chamber deposit Interference). Here is a link or two:

http://www.sae.org/technical/papers/940385

http://kereta.info/what-is-the-effect-of-e...ngine-deposits/
 

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QUOTE (kevin s @ May 26 2010, 07:10 AM) index.php?act=findpost&pid=326464
Got an 07 sonata V6 as a loaner, it has the startup knock too. Is it just me or have any of you had this kind of knock too?
Is it truly a knock (also called "spark knock"), or tappet noise caused by cold start?

Spark knocks are easy to detect, as they're loud and make the engine run roughly. Tappet
noise is harder to hear, and often can't be heard inside a closed cabin. Tappet noise usually
doesn't cause the engine to run roughly, it can be heard but not felt.

Slight tappet noise is normal until oil pressure comes up. Spark knock that lasts more
than a few seconds is not normal, and can be destructive. It needs fixing right away, and
is probably computer or sensor related. Sometimes it's water in the gasoline, which could
explain 3 cars from that dealer making noise.

The faulty timing chain tensioner some V6 owners have experienced makes an awful grinding
noise.
 

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My Santa Fe's V6 knocks just a little bit at first start up but only until the oil circulates and gets everything lubricated. The longer it's been sitting, the more likely it is to do it. The car's been sitting since about 11 PM last night and hasn't been touched since. I'm probably going to go out later so I'll try to see if I can catch it on video for you and see if it's anything like what you've been experiencing.
 

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I am still trying to get a good video of it, but my phone really sucks, in car I can hear it, but on phone it sounds like a rumble, I will keep trying to get a good video then post it on youtube, then link to it.
 

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weather has warmed up quite a bit here over the past month or so, I dont really hear the startup knock as much as before, it is still there just not so pronounced unless its colder when I start it up.
I am still trying to get a vid of it, will keep trying.
 

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Took my car to the dealer again today, showed them the video, and took Tech on a drive to hear knocking noise in motor.
Tech did not hear noise from motor, I heard it the whole time, Tech told me that the fuzzy logic in the car is picking up on what I am doing and causes the knocking noise or other noises that I hear.(something doesnt seem right to me).
Also Tech told me that the clacking/knocking noises in the video is my transmission switching bands or something similiar. (again, something don't seem right to me).
Any opinions on the noise?, I am thinking rod knock.
Tech says when I hear a loud noise and have to have it towed in with pieces falling out of it, that's when they will find the problem.
 

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QUOTE (kevin s @ Jul 10 2010, 04:59 AM) index.php?act=findpost&pid=340480
on the noise?, I am thinking rod knock.
Tech says when I hear a loud noise and have to have it towed in with pieces falling out of it, that's when they will find the problem.
Very reassuring tech you have there. :)

Do you know the difference in once per revolution and once per 2 revolution sounds?

Crankshaft noises such as knocking rods repeat once per rev. They usually make a
"rattling-knocking" sound that changes character under various engine loads. Close
examination of oil filter often reveals more fine metal particles than normal.

Camshaft noises repeat once per every 2 engine revolutions. They usually make a "tapping"
sound that change a bit with engine temperature, but not with engine load. Some valve train
noise is normal on DOHC valve trains. There are no traditional hydraulic lifters keep the
slack out of the parts. All-aluminum engines transmit sound better than iron, so there's a
double whammy. These engines are LOUD under the hood, but not in the cabin. Some
people are more sensitive to noise than others, and that may be the whole problem.

Any mechanic worth his salt can tell the difference in crankshaft and camshaft noise. Get
a mechanically inclined friend or relative to take a listen.
 

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What you describe is the classic timing chain tensioner problem for the V6 and not the I4. There is a TSB for it. They are SUPPOSED to fix it under warranty, but it's a tremendous PITA because they almost have to remove the motor to do it. So I think they shy away from it. The TSB talks about how if the tech is able to observe the problem, then they will repair under warranty.
 

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ok I have a vid of the knock, it is very hard to pick up from inside the car, the sound is also very quiet on the vid, (stupid phone), if yu have earphones it should be easy to hear as the RPM's are raised a little bit. 2 vids but they are quiet.

http://www.youtube.com/watch?v=1AM_S5Tcro0

http://www.youtube.com/watch?v=GVfp6jTYFLY

Please tell me what you think, also about 3 months ago when I took the car to dealership, they still could not hear the noise,
also it has sounded like this since about 28,000 miles in may of 2010, now there are some 34,000 some odd miles on it, would a rod knock continue for this long?
 

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Anyone could mean power steering fluid needs changing. After doing mine, I no longer hear a whine. Fluid change 9 months ago, first winter here no problems. I don't hear anything in the videos, perhaps you should step outside. A rod knocking would have failed. Ticking is normal I hear it in mine all the time.
 

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Is there a reason you recorded from INSIDE the car? Wouldn't you get a better result if you recorded from the FRONT of the car with the hood UP? I can't hear much of anything.
 

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On cold mornings I hear lifter noises, piston slap, valve train clatters and it's twice as loud in my Sequoia with a v8. One of the joys of newer cars is all the lightweight aluminum parts but some stuff still needs to be steel which expand at different rates and need respective tolerances. Forums for all the manufacturers are loaded with the same complaints. One of the joys of the Sonata is that it is a very quiet interior which allows you to hear these noises better.

Driving back and forth to work the last 2-3 weeks I've been starting to hear a buzz vibration at about 3000 rpm (a muffled version of my 3800 RPM buzz I've had for 4 years and 76k miles search my posts coming from exhaust flex pipe). When I have time I'm going to try a vibration damper from another vehicle that mounts them on the exhaust for the same reasons to see if it changes it.

OP,
profile doesn't list where you are for others to understand correct temperature scenarios. Tomorrow night here in NY is supposed to be 3 degrees F. Should be REAL noisey on startups of both vehicles.

What oil are you using? Factory filters or fram? I don't know if it was here or some other forum where I was reading some oil topics and many new cars are going to 0W-20 (or 30) weight oils as it allows better cold flow with same warm demands. Maybe your dealer is using something too thick? I've done numerous oil analysis on my Sequoia and the Sonata and all show nothing out of the ordinary except a little high iron in the Sonata. Comments from Blackstone where it was normal if the car sees any "racing" which when I called them they clarified. It's my DD but I bought a stick shift for a reason and like driving it. It frequently sees higher RPMS in 1-2-3 gears and then traffic has me at 3000 rpms pretty consistently. I also "heard" :whistling: that the rev limiter kicks in around 6200 RPM so you don't blow the motor which fit their "racing" category.

My old Corolla had a lot of startup noises that after switching back to factory filters I realized was from the FRAM filters I was using allowing all the oil to drain out of it when it sat. After cutting an old one open I saw why and haven't used FRAM since. Not sure how it would be on the Sonata because the filter sits facing up so no where to really drain out. The Corolla was mounted sideways by the top of the motor allowing it drain very easily back into motor.
 
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