Sometimes when the belts are changed and tensioned a little more than it was previously, the bearings on the alternator might just be pushed over the edge - run it for a short time with these belts off and see if the noise/knock stops, and if it doesn't, it might be something more serious like valve timing or worn engine bearings.
When last was the timing belt changed - has the performance changed? - have the mechanic check the valve timing and condition of the timing belt.

 

I had the timing belt checked not long ago and it is ok. I will be changing it within the next 20,000km. I will try to have them remove the belts to check whether it is has been tightened too much or not. As for the valve timing, are you referring to the valve springs? If so, then no i haven't had them checked since acquiring the vehicle in november 2011. I was wondering if it is worth a shot to check the engine mounts because i can feel a bit of engine vibration too. Thanks.

 

I had the timing belt checked not long ago and it is ok. I will be changing it within the next 20,000km.

What is the mileage on the current belt?
Typically the belt is not checked, it is replaced at the manufactures recommended interval.
There's no reliable way to really check the condition of the belt - of course you can tell when it's really bad, but you cant tell how much life is still left in a belt that appears good in a visual inspection.
Part of installing the timing belt is to ensure that the valve timing marks are correctly aligned - if the belt degrades and jumps a tooth, then the valve timing can shift, and depending on how far it shifts, the pistons could strike the valves.

I will try to have them remove the belts to check whether it is has been tightened too much or not. As for the valve timing, are you referring to the valve springs? If so, then no i haven't had them checked since acquiring the vehicle in november 2011. I was wondering if it is worth a shot to check the engine mounts because i can feel a bit of engine vibration too. Thanks.

It doesn't take much to check the engine mounts, and if their rubber cushions are bad it could also transfer a "knock" to the cabin.

 

I am not sure how much life is on the actual timing belt, but the car has approx 167xxx km on it, so i suspect it has been changed somewhere in the 80-100xxx range. I had the belt and timing visually inspected by a good mechanic friend of mine and he said there is nothing to worry about at that point in time (about a month or 2 ago).

 

I am not sure how much life is on the actual timing belt, but the car has approx 167xxx km on it, so i suspect it has been changed somewhere in the 80-100xxx range. I had the belt and timing visually inspected by a good mechanic friend of mine and he said there is nothing to worry about at that point in time (about a month or 2 ago).

With this engine (interference engine) you are living very dangerously.

There is no mechanic out there that can tell you that the belt is good for "X" miles based on a visual inspection, so disregard what you heard from your good mechanic friend.

It is likely that you are way past the manufacturers recommended replacement interval of 60K miles or 5 years - if the belt slips, you're looking at buying a new engine.

http://www.kia-forums.com/kia-rio-forum/34914-diy-timing-belt-warning-interference-engine.html

 

So the consensus on the knocking noise has been narrowed down to the alternator being a bit loose on the bottom bracket. The motor now runs smooth and quiet, but I will definitely get on top of that timing belt issue too, thanks.

 

Good to hear that you got it sorted and it was a simple and cheap fix, and thanks for reporting back.

Take care of that ticking time bomb timing belt ASAP.