does a 2005 hyundai sonata gls/lx 2.7L v6 have a timing belt or timing chain?

First of all, if your 2.7 liter 05 Sonata camshaft/crankshaft lines are out of order, don't worry. In order to line up the marks on the camshaft and crankshaft sprocket, you must rotate one camshaft at a time, 1/4 (one quarter) of a turn, only, then stop to rotate the other the same. When you rotate a camshaft, do it clockwise only. Put a socket wrench on the bolt in the center, 15mm I believe. When you turn one crankshaft, it will resist and then suddenly turn about one quarter turn and stop. Don't push too hard. Be gentle. Because sometimes the camshaft will not turn unless you unfreeze the crankshaft at the bottom (22mm bolt). Then you must rotate the other camshaft, (intake & exhaust-both above the crankshaft below). Do the other one quarter of a turn. If neither will turn, then you must rotate the crankshaft sprocket. The crankshaft (behind front passenger wheel) is able to be rotated just a little bit counterclockwise(carefully), as well as clockwise(proper), which will unfreeze the camshafts. A sprocket spanner wrench can be used on the crankshaft pully to turn the crankshaft, or to hold it in place while unloosing the 22mm bolt. This wrench consists of two prongs (adjustable) which are placed inside of the two crankshaft pully holes, to hold it in place, or to turn it. These crankshaft pullys often freeze onto the gear, during removal and a harmonic balancer, pully puller can be used, which places two bolts into the two holes (threads must be created), so having the right size bolt may require buying an extra at a home department store. These two bolts hold a bracket in place, in which a 3rd bolt will screw through the center, pushing out the crankshaft pully. Sometimes, the pully puller bolt will not fit into the crankshaft, therefore placing a smaller bolt inside of the crankshaft hole will act as leverage for the pully puller bolt to press against.

It appears it has both a camshaft timing chain and a timing belt according to the parts chart for a 2005 Hyundai Sonata V6 2.7L Old Body Style 4 door car. The cam shaft chain is part number 24321-37100, and the timing belt is part number 24312-37400 (replaced by part number 24312-37500). I found a description on a different engine of how exactly a cam shaft chain and a timing belt work together in the same engine (it may be similar here): "On the [Engine 1 - 8 valves - with only timing belt], valve timing for both the intake and exhaust valves is accomplished by a single overhead camshaft. The [Engine 2 - 16 valves - with both camshaft chain and timing belt], have two camshafts, one for the intake valves and one for the exhaust valves. On these cars, the exhaust valve camshaft is driven by a camshaft sprocket directly from the timing belt, identical to the [Engine 1] cars. However, the exhaust and intake camshafts have a toothed gear located near the center of the shaft. A chain between the exhaust and intake cam allows the exhaust camshaft to drive the intake camshaft. The drive chain tension is maintained by an oil fed tensioner. Over time, the tensioner will eventually wear out..." ( http://www.clarks-garage.com/shop-manual/cam-04.htm ). A picture of this can be seen by the following link - notice the camshaft chain is at the top of the right head of the overhead cam - coupling intake and exhaust camshafts: https://i1.wp.com/kingbain.com/wp-content/uploads/2013/12/81jMQOD2pKL._SL1500_.jpg?resize=768%2C677&ssl=1