Hello everyone. I've noticed, since we purchased our 2011 Sonata, the engine is a little thrashy sounding @@ cold fire up. Not so much valve noise, but sounds more like chain or tensioner noise. After about 15-20 secs it dies down. Only @ cold startup. I hesitate to leave with dealer (overnight since it has to be stone cold) only to find out it is "normal."

Can anybody comment? Oil and filter has been changed once @ 1300 miles, currently running Castrol 5W30, no change though. Oil level is full. Car has 1900 miles on it.

Thank you.

Jim

 

What oil filter did you use? If it's not an OEM Hyundai it can cause that noise.

 

It's an OEM filter from dealer I installed. (This noise has been there since we bought the car.)

 

Likely normal high pressure pump sound... let sit, remove black plastic cover the night before, and listen while assistant start car while you hover over engine and listen. Put hand on pump/solenoid and feel if noise jives whit pump feel..

 

I suspected it may be DI high pressure pump (like a diesel sound on fire up). I did fire it last night @ 10pm after it sat for 5 hr and it does sound like it is near chain (passenger side of cam cover), though it was dark outside. Almost has the sound like a bad alternator bearing. But it's not coming from alternator, it's higher in eng comp.
At least the noise hasn't changed, which is comforting. If it were tensioner rail/tensioner/chain I would think it would be getting noisier.

 

Oil filter anti-drain back valve fail, allowing oil to drain from the top of the motor back down to the bottom end?

 

Well I guess this begs the question:

Should the injection pump/solenoid be noisy when cold?

Thank you!

Jim

 

Direct injection engines like ours operate at MUCH higher PSI than standard fuel injected engines. I too have noticed that initial thrashiness of this engine, but have put it down to the higher PSI in the cylinders.
Other FI engines I have had clicked more loudly on start up (and quietly even afterward).
These engines have Mobil 1 in them from the factory, which is reputed to have very good start up lubing characteristics, so I would not worry about the louder sounds at start up at all............