[dmercado]

I Have a '94 MKIV auto with low mileage and I seem to be spending more and more money just to find out what is wrong. Maybe you can help diagnose my problem.

Here is my problem:

A rhythmic humming sound, fairly audible at speeds above 60 km/hr --> sound and feeling seems to come from the front end of the car and feels as if one of the front tire radials are rubbing the road the wrong way.

As I increase the speed the rhythmic humming sound still exists but with a higher rhythm.

I have had the car looked at by a couple of Toyota dealerships. I have recently completed:
1) Wheel balancing
2) Left Rear wheel bearing replacement
3) An alignment.

Please let me know what you think.

Thanks.

 

[supra_10]

Going by my gut, it doesn't sound as if it's speed related.
60 km/hr is less then 40mph and it's too low a speed for wheel balance issue, etc.
To check for possible vibes coming from a loose part, related to RPM, I'd try first to lock the tranny in first gear and drive it to same RPM that you reach normally at 60 km/hr and then repeat at 2nd gear.
Then I'd try same RPM range without driving at all.

Any loose screw/washer or any other parts can cause this kind of humming. Try to evaluate the pitch and frequency and try to match it to a possible small/large loose part or solid vs sheet metal, etc.
Also, broken/loose pieces in a cat (if you have one) may manifest itself in some cases with humming vibes.

Good luck!

Jay

 

[dmercado]

Got my car back from the dealership after they completed an adjustment to the parking break and re-checked the alignment.

This was their diagnosis for the humming in the front-end:
"WORN/FEATHERED/OUT OF ROUND TIRES... TIRES MUST FIRST BE REPLACED FIRST TO ELIMINATE MOST OBVIOUS CAUSE"

Now they are correct with the fact that my tires' tread is close to looking bald.

Any experience with "WORN/FEATHERED/OUT OF ROUND TIRES..."? Do you get any bad rubbing with tires, hence causing a rhythmic humming, in this condition?