Hyundai Repair: kia with 2.4 hyundai engine, balance shaft, mechanic check

Question
QUESTION: Hello
My timing belt and balance shaft belt were just changed at 51,000 miles . The car now sounds very loud at highway speed and also has a vibration . How would the timing belt change cause this? Thanks

Bob
ANSWER: If either of the vehicle's balance shaft belts are improperly timed, this will cause a vibration from the engine which varies with engine speed.  You'll be able to feel it simply by revving the engine in neutral or park.  

If the vibration occurs only when moving, it's likely not related to the timing/balance shaft belt replacement.

---------- FOLLOW-UP ----------

QUESTION: Hi
 If the balance shaft belts are out of time will this damage the engine, and how would the mechanic check for this?

thanks Bob
ANSWER: The only way to check this would be to remove the timing covers.  

The rear balance shaft is a simple matter of checking the marks.  

The front balance shaft, on the other hand, is a royal pain to check with the belt in place.  The sprocket turns in a 2:3 ratio with the balance shaft shaft, so even if the marks line up, the balance shaft may be 180 degrees out of phase.  

There's a bolt (which Hyundai has cleverly placed behind the exhaust manifold) which can be removed to insert a screwdriver to check to see whether the balance shaft is correctly timed.  If the marks align and the screwdriver fully inserts, the shaft is timed properly.  If the screwdriver doesn't fully insert, the shaft is improperly timed.  But you probably cannot perform this test without removing the exhaust manifold.

I think it'll probably be easier to align all the timing marks and then remove the timing belt.  Then turn the front balance shaft sprocket a small amount.  If it tends to continue turning, the shaft was improperly timed.  If it tends to return to its original position, the shaft was properly timed.

---------- FOLLOW-UP ----------

QUESTION: Hi
If they are out of alighnment will it damage the engine? It could take some time to convince the mechanic to take it apart and check them and I need wheels everyday.

Thanks Bob

Answer
Sorry, Bob.  You asked that as part of the previous question and I neglected to answer it.  

I don't foresee any measureable damage over a short period of time.  The real consequence is that there's a high frequency engine vibration that can stress a number of parts of the vehicle, both inside and out, mostly leading to rattles and such.  As for serious engine damage, I'd doubt it.