If your Hyundai Sonata idles rough, is sluggish, clattering or backfiring, your timing chain probably needs replacing. The timing belt keeps your car's crankshaft and camshaft valves opening and shutting in synch with the pistons. Checking and replacing the belt regularly prevents breakage and serious engine damage and helps you avoid being stranded on the highway.
Check your owner's manual for the recommended mileage for replacing your timing belt. Replacement for Hyundai Sonatas is 60,000 miles.
Locate the timing belt and examine it for breaks, damage, fraying, worn spots or looseness.
Inspect the belt for cracked or missing teeth that may be the result of foreign material collecting between them.
Determine if the timing belt damage is on both sides. Single-side damage may be caused by the timing belt's guide.
Disengage the negative battery cable.
Turn the tensioner arm to the right 14° and take the timing belt off its pulley.
Take out the coolant pump, idler, tensioner and crankshaft pulleys and both timing belt covers.
Remove the engine's mounting insulator and mount bracket and the auto tensioner.
Align the crankshaft's timing mark so the first cylinder piston is at "Top Dead Center" (TDC). The camshaft sprocket and cylinder head cover timing marks also should align.
Unfasten the timing belt.
Examine the cam and crankshaft sprockets. Replace if there is excessive wear or other damage.
Position the new timing belt on the sprockets.
Relax the timing belt tensioner so it can make contact with the belt. Adjust the belt to the tension recommended in your vehicle owner's manual. Also align the timing indicators on the cam, crank and other sprockets.
Return the engine to the 0° mark by turning it two revolutions in the direction of travel.
Secure the timing belt cover and reinstall whatever was removed to access the timing cover.
Reconnect the negative battery cable and any other items that were disconnected.
Start the engine and look for leaks.
