Increased engine noise after timing belt replacement and 60k service


I had a 60k service done on my car (which included timing belt replacement). The shop recommended replacing 3 other belts and since they were only $25 a piece I said ok. One of them was the balance shaft belt. However, after the service the car engine makes extra noise and vibration at about 2500 rpm. Since the automatic gear shift is around this number the noise goes away for lower gears. But in the 4th gear when I drive at 65-70 mph the noise stays (I guess because rpm stays around 25k). Before the service this excess noise was not present. I took it back to the shop and they blamed it on wheel balancing saying that since the service included tire rotation the rear wheels which were not balanced came in the front and cause this issue. They offered to do balancing for $60. Since I got the tires installed at Costco and I believe they balance them during installation, I did not buy the “rear wheels not balanced” explanation. So I asked them to switch the tires back instead for $20 (payable only if the problem goes away). But the problem is still there.

Is there anything that a mechanic can messup that will cause this noise and vibration…after some googling I found that the engine foundation being loose etc can cause something like this. Some pointed to misfiring of the engine…I did get spark plugs and ignition cables replaced as part of the 60k service. Also misfiring should probably happen at all rpms?

Any advice on what I should do? I am thinking of taking the car to Costco for free rotation and balancing (since the rotation was reversed by this mechanic) and my car to another mechanic to check the noise problem. I do have 6 month warranty for the service…does that mean I can make this mechanic pay for the repairs done by the new mechanic?


Is this noise and vibration present when the engine is revved and the car is stationary? If so, then my guess is that the timing belt is off or the balance shaft is not timed correctly.

I agree with OK4450. It sounds like the balance shaft was not timed properly before installation of the belt. ! tooth off on this shaft will give you an engine vibration at 2000-2500 rpm. Driving it this way will cause other failures.

if they are putting you off about looking at it again I would send a cerifield letter that they sign for so when 6months are up they tell the judge the 6 months are gone and you never came back to them send one each week . did they show that the rear tires had no weights on rims.
$60 to balance two wheels this should have been only $20.00 at most. was this pep—? sounds like their work