Reader asks about a strange vibration

Wheels: Steve B. from Oregon asks: "I hope you can help. My company car is a Dodge minivan and I like the vehicle but recently, I attended a conference in Seattle and I had a vibration problem when driving at highway speeds. When the speed limit was 65 MPH, the van rode great and very smoothly. When the speed limit changed to 70 MPH and I sped up, however, the whole front end started to shake. The dash rattled and it seemed as if the car was going to shake itself apart. I had to continue the trip up to Seattle and back at 65 MPH to avoid being shaken up. When I returned, I had a local shop check out the front tires and suspension and everything was normal, including the tires and tire balance. The shop was able to verify the condition, but did not know the cause. The owner of the van authorized replacing all four tires; this did not solve the problem. The wheels were also checked for runout and they were found to be almost perfect. Any ideas?"

Halderman: If a vibration is felt or seen in the dash, this usually indicates a fault with the front wheels or tires. Because these and everything in the front suspension has been checked, this leads me to think outside the box. I experienced a similar situation when test driving a customer's pickup truck. At lower speeds, everything was smooth, but when a certain speed was reached, the hood started to shake, and the dash and steering wheel began to shake, too. It turned out that the owner said that it was fine until he installed a bug shield on the front edge of the hood. To check to see if this was the cause, the bug shield was removed and the vibration problem did not occur. Therefore, check to see if there is an aftermarket bug shield or a covering over the front of the vehicle. If so, try removing it to verify that this is the cause.

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