I too have had the 2004 KIA Sorrento crank shaft bolt break twice. Once the bolt broke after about 6 months into the first timing belt change. I took it to the dealer and they were going to charge me $150 to see if it was broken, and then refund me the money when they fix it. It was 30 days from the recall cutoff. The bolt partially came out then seized in the crank shaft. Upon removal the bolt then snapped off. I then drilled out the center, put in an extractor and the extractor snapped off. I then tapped out the bolt with a smaller tap then went to the same size as the bolt thread tap. I replaced the bolt with a new bolt. Three years later it broke again. This time I used the centering jig from [url]https://brokencrankshaftbolt.com/[/url] this made it much easier drilling out the center of the bolt. I heated the bolt to remove any lock tight and the bolt came right out with an extractor. I then drilled out the crank shaft and put in a 5/8 grade 8 bolt with a “spider’ type lock washer and lock tight. The fix seems to be working great. I think the “Heavy Headed” original bolt is a very bad design, as the thick massive bolt head is actually longer then the bolt, causing centrifugal forces that aren’t needed. The standard grade 8 bolt, as used on most crank shafts, seems to work great. I also had to drill out the new harmonic balancer and washer to accommodate the larger 5/8′s bolt. I will try the softer belt tighten technique too. The fact that the harmonic balancer almost sits flush on the end of the crank shaft with no woodruff key (just a roll pin) seems to be a bad design too (have not ever seen this done). This 2004 Sorrento now has 160K on it. Very strong engine, still has a drinking problem.
Update:
I have had the crank shaft bolt break 2x and unscrew 2x. I have learned a lot. Taped out the crank shaft to receive a larger grade 8 bolt. As well as made the hole larger on the washer and Harmonic balancer pulley. Put a star lock washer on it. Torqued to 130lb with lock tight RED. A year later it loosened and sheared the timing gear pin (this is much better then shearing off inside the crank shaft like before). Bought another harmonic balancer and crank timing gear. This time I’m putting on a very heavy duty grade 8 lock washer and lock tight RED & 130lbs torque. Also put in 2 more pins in the timing gear at my local machine shop see attached pictures. So this gives it a total of three pins between the crank shaft timing gear and the harmonic balancer.
I spoke to the local Kia parts dealer and he said this engine is in 2 other Kia’s but transverse mounted with no problems. My theory is there is so much weight out there that it pulls itself apart moving up and down from the road. Since there is no woodruff key on the harmonic balancer and it doesn’t slide onto the crank shaft (like every other engine on the road) I thought 2 more pins might keep the slipping at bay. The balancer pulleys gotta weigh 15-20lbs and that’s a lot of weight spinning out there on one bolt. It’s just a bad design that needs help. I’ll repost if this doesn’t work. I should sell it but it’s the kid’s college car and other then the “y” in the heater hose and all the plastic covers turning into crayon and the head lights burning out every 6 months, and the drinking problem , , , , , it’s been a pretty good car. Mark Peveler702-379-7357 MarkPeveler@cox.net
UPDATE 28OCT14
This fix failed one year out, but the bolt didn’t break or cross thread. I will either tap in 3 or 4 flat head screws with hex drive or threaded in studs, then sand blast all compression surfaces. I will cross hatch washer as well. The Sorrento has 188K. It’s paid for and I don’t want car payments so I’ll fix it again. The benefit with the bigger bolt is it didn’t break, just lost power steering. Still ran well even though pulley didn’t turn.
UPDATE 8DEC14
New Pulley/Harmonic Balance and timing belt gear. Put in 3 Allen cap screws though pulley and into gear. Cap screws sit proud and washer was cut to allow protruding cap screws into washer. Instead of #130 lbs torque I went with #150 lbs torque on the 5/8 Grade 8 bolt. Protruding allen cap head screws should keep any movement between gear and pulley as well as washer sliding. A 6 month torque check will be in order.
Post time: Jun-12-2017