My wife had been complaing of a noise on startup which I was unbale to reproduce until today. After the car had sat for about 24 hours when I went to start it up it cranked fine and once it started and you let off the key it makes a very loud ratlle for a few seconds and goes away. I shut it off and tried to restart it immediatly and the noise was gone. This is louder than a valve train rattle or a chain slap. It goes away immediatly after the first start, which rules out the engine warming up ect...
It almost sounds to me like the starter solenoid is not disengaging and "free spinning" against the flywheel. And after that initial start the solenoid moves freely. Anyone experience anything like this before?
Never had it in my Sorento, but my old '98 Silverado had it happen - caused by the bendix drive on the starter to be sticky - usually due to lubrication failing and corrosion starting to form. A bendix drive is basically a spiral groove in the drive shaft of the starter, with a gear that has a matching inner cog that rides in that spiral, and a spring pushing the gear back toward the starter motor. When you engage the key, the mass of the gear itself doesn't "want" to start spinning, but the starter shaft is spinning very fast. This "kicks" the gear up the spiral against the spring and into contact with the ring gear on the engine's flywheel. The load of the ring gear engaging with the starter gear keeps "pushing" the gear up the spiral against the spring and keeping it engaged with the ring gear until the engine "over-runs" the starter (spins faster than the starter is spinning) - once this happens the small starter gear is no longer being pushed up the spiral ramp of the starter shaft, and the spring forces the gear back toward the starter and out of the ring gear. You release the key or the "push button start sensor" determines the engine is running and the starter stops spinning, the gear is disengaged fully by the spring and all is well.
If the spiral ramp on the starter shaft, or the inside of the starter gear that rides in that spiral, aren't well lubricated anymore, or start to corrode, two things can happen - 1. the starter spins and the gear never flies up and engages - this sounds like "whirr" "whirr" with no engagement or turnover of the engine. This is common if the corrosion or lack of lubrication is near the starter end of the shaft. 2. The gear flies up the ramp fine when you go to start, but then when the engine fires and it tries to kick the gear back down the spring doesn't push it all the way back. The over-running of the ring gear on the engine flywheel forces it back until the point where the teeth just disengage enough that it's not spinning the gear back down the shaft, but unfortunately the edges of the teeth will chatter.
Get it fixed immediately. It will likely be a rebuilt starter is your cheapest option if you're out of warranty. If you're still in warranty a new starter is called for. If you don't get it fixed, every time you hear that chatter there's impact damage between the bendix drive gear on the starter and the ring gear on your flywheel. If the ring gear teeth get damaged enough (not that hard to have happen) the starter gear won't be able to engage it properly any longer, and you'll not only need a new starter but a whole new flywheel and ring gear - which usually means the engine has to be pulled and a pretty big disassembly project takes place. If you're paying the bill a new starter will be a few hundred $ installed (probably about $550). If you wait until the ring gear is damaged from those impacts, you're probably closer to $2000 for the repair.
Never assume that it could be the lesser evil, starter, when it could be an oil supply pressure problem.
Consider getting an oil pressure gauge and monitor the pressure during starts that are noisy and normal running at temperature.
When last was it serviced and what oil filters being used - the wrong, or non-OEM filters could do this - filters with poor ant-drain valves could cause this.
I have the same issue. Dealer had it for a day trying to reproduce the noise through out the day but no luck. I was able to record the sound on my phone though you can't tell where it's coming from. I played it for several people in the service department but they don't know what it is.
I had a lengthy sit down talk with my service manager today about the noise and it turns out there is a TSB (140, Rev 1) from Feb 2014 for 3.5L produced from Oct 26,2009 to Jul 14, 2012. Why this wasn't told to me last March I have no idea. It involves replacing the intake CVVTs and intake camshafts. He's putting a request to KIA corp to OK the work. I'll update this thread when I have an answer to the request.
I had a lengthy sit down talk with my service manager today about the noise and it turns out there is a TSB (140, Rev 1) from Feb 2014 for 3.5L produced from Oct 26,2009 to Jul 14, 2012. Why this wasn't told to me last March I have no idea. It involves replacing the intake CVVTs and intake camshafts. He's putting a request to KIA corp to OK the work. I'll update this thread when I have an answer to the request.
Bendix,aka, state solenoid may need attention. Disconnect your batery and get under it to check to make sure the electrical leads to it are tight and corrosion free.; make sure the electric posts coming out of starter solenoid are tight.
Sounds like the return spring in Bendix is wearing out and starter pinion gear remain in contact w flywheel teeth - this is probably due to bearing wesring in starter solenoid to pinion shaft is wearing in the exrended or engaged position
I mentioned the starter to the service manager but he feels it's the CVVTs. There was an audio file attached to the TSB and it did sound similar. The thing that's pissing me off is unless they get paid they don't want to put any work into diagnosing the issue other than look on their computer.
Attached is the audio file per the Service bulletin. If this is the noise you are hearing I'd recommend bringing it to your dealer and letting them check it out. Note be sure to leave it with them overnight so they can check it in the AM/Cold to verify. This is a common issue on the MPI 3.5l engines. This will be covered under Kia's 10yr/100k powertrain warranty. Starter Bendix's sticking are highly uncommon on this model, but anything is possible
Thank you for this, also to cmack for the photos of the tsb. But is there anyway you can include the after startup file / sound? It would be greatly appreciated, as the tsb states some valve train noise is normal and is included in the 2nd / after audio file. Thanks
I had clatter for 5-10 seconds after cold start since we bought our used 2011. We bought it with 22K on it back in 2012. One week after we bought it it was taken to the dealer for warranty work and I mentioned the staaartup noise. We were told it was normal.
Fast forward to 4 weeks ago and 57K miles. I had taken it in for some small issues and an alignment. I mentioned the noise and the service manager said I should leave it overnight so they could hear it cold. Long story short, I picked it up a week ago with a brand spanky new motor. Diagnosis was bad rod bearing. Caught that just in time, not being the original owner my drive train warranty goes bye bye at 60K.
I really can't say enough good about how well I was treated by everyone at the dealership. Other than this the Sorento has not had any other issues outside of normal replacement items. I've been so happy with it we just bought a 2015 Optima EX.
The issue is with the 3.5 V6, which I also have in my wife's 2011 Hyundai Santa Fe... I also have the clatter sound and am currently trying to find out if the TSB will be honored by Hyundai. Would also be nice to know, if this repair does not get done, will the engine still be reliable for 200K miles plus... This is not a normal drivetrain sound.
I had a Chrysler, K-car convertible yrs ago making a similar starting noise, and so did my elderly neighbor (with his K-car hardtop). It drove me nuts! Finally had a local gas station put it on the lift, and I found a loose vibration damper pulley. Tightened the bolts, and it was just like new again! :thumbsup:
Car went in Monday for the startup noise TSB & shift interlock recall and got a call today saying it's done. I guess time will tell if it really fixed the noise.
Around 100K. I did an oil change (had been a while) and it was a bit sludgy. After changing the oil the sound got better so i think your right they just do this on startup. I am going to do a few more oil changes and see what happens.