I'd go with Kia's recommendation but also look at the how many months they suggest to go with.
If you research alot, I think you will find more belts go back based on years of service vs miles.
That rubber belt on a car 10 years old with only 10K needs to be changed asap. Rubber deteriorates over time more than mileage. IMHO.
If you see my '05 LS430 with only 85K. It's almost 15 years old. I changed the belts as soon as I purchased it 15K ago. I changed on time, not mileage.
Check the belt for any excessive cracking or chunks out of it. If Hyundai-Kia used a spring-loaded tensioner there might be a scale with two ranges, an normal one and one indicating to replace the belt.
OEM belts can go a long time, but replacing one out of PM can't hurt. EPDM belts doesn't exhibit the same modes of failure as an neoprene belt does.
Thank God , I have never had a serpentine belt fail . I have always tried to observe their condition and replace them when they became " cracked " .
I always try to keep an old belt in the trunk , just in case one does go bad . To use in such a case , as a spare , until I could source a new one .
You might consider doing that .
We purchased our 2006 Buick Lacrosse 3.8l , a couple of years ago , with ~ 36,000 true miles on it . I knew this was not enough miles to justify replacement of the " rubber products " , under the hook . But it was over 10 years old and I am getting old enough that I do not wish to do emergency repairs , out in the middle of nowhere . And there is a lot of open road in Texas . ( Especially if it could be avoided by aggressive preventative maintenance . )
I made a list and started ordering parts from RockAuto.com and purchasing parts locally . I sourced DEXCOOL , both radiator hoses , both heater hoses , serpentine belt , tstat , PCV valve , PS fluid , brake fluid , ATF Dexron 6 , hood and trunk lift struts . Dealer had changed the engine oil before we accepted delivery of the car .
Looking on the internet , I discovered the potential of the 2 plastic coolant elbows . Sourced / installed metal replacements for them , too . The old ones still looked good . ) The hoses would have probably been fine , also , but I replaced them anyway .
Replaced almost all of those parts . The tires still had good tread , so have not messed with them , yet . Turns out the serpentine belt still looked pretty good , so I re-used it & put the new one in the trunk .
Used a suction pump to suck out fluids and replaced with new fluids . Added 1 gallon of DEXCOOL , after replacing the radiator hoses .
Brake pads seem fine , have not messed with them . A/C still working fine , as of a few weeks ago . No work done on that system . Same with tires . Oil / filter has been changed a few times with dino oil ( DEXOS is not required / indicated ) at around 3000 - 4000 miles .
So far , we have made several trips in the Buick and had no problems , thankfully . I consider it money and labor well spent , DIY , for preventive maintenance .
As a point of reference, our 2010 Sienna is on its original serpentine belt at 205k miles. It looks perfectly fine; I'm not the slightest bit worried about it.
I'd say 100k would be plenty conservative, and you could likely go far longer than that!
Since the introduction of EPDM rubber belts, I think serp belts are way over engineered (this is a good thing) Replacement at 100,000 miles for me would fall under special circumstances if it obviously needed it.
I had a 2004 GMC Sierra, still had a mechanical clutch fan that year and I got rid of that truck at 195,000 miles with the original GM belt still looking fine, no cracking, also the original AC belt, no cracking. Currently the wife drives a 2007 Camry still rocking the original belt at 242,000 miles and counting. Zero cracks, the ridges aren't even sharp indicating a worn out belt.
Serpentine belts today are not like the belts from the 70's and 80's. they are much more durable and last much longer. 100k miles seems right although I didn't change the belt in my 2006 Camry until well after 150k miles, that was only because there was cracking.
I would have your mechanic check your belt when you have your car serviced so you have peace of mind.
The dealer wanted $129 to change a $30 ac delco belt on my 08 impala. I changed it myself but at 111k the original was in almost new condition. Literally took 10 minutes. I think I need to start a shop that just changes belts only for $69. I'd be rich.
I changed my OEM belt at 135k, not because it needed it, because I got the belt on sale and figured 135k I got good service from the OEM, plus a easy quick thing to do.
Once I got the OEM belt out, I was surprised how good it still was so I tossed it in the back cargo area with the wrench I used zip-tied to it for the spring tension pulley. The OEM belt could have gone on but whats done is done - so have a good spare on board now.
I replaced the OEM with a Bando belt that was on sale for $11.00 and after felt why did I cheap'n out on a belt, but now with 50k on the replacement belt it looks like it does fine with a visual check each OC.
Back in the day I was used to changing the ol v-belts kind of often and periodically adjusting (tightening) the tension. Then one day I got a vehicle with that thin looking serpentine belt and probably scratched a few hairs off wondering how long this thing is going to last and how often I should replace it. They seem to be proven durable. Same thing with the belt on my Harley. Seems kind of thin, and it powers the rear wheel instead of an accessory, but it keeps going and going and looks fine. I'm careful every time I remove/replace the back wheel on how I align it to run on the pulley, rear wheel turning forward. I don't carry a spare belt for the Harley.