UNDER THE HOOD: Troubleshooting that annoying ‘chirping’ sound from behind the dash
By Brad Bergholdt, Knight Ridder Newspapers
12/26/2003
Q. I have a ’94 Explorer, which I enjoy very much. In the past two years a sound has developed that no one — and I mean no one — seems to be able to fix.
It only occurs when it is cold outside. The sound comes from behind the dash area in front of the driver. It is a chirping-type sound. It starts when I have increased the speed past 40 mph. After about two miles, it seems to quit. I have had the fan belt replaced twice and the speedometer cable has been replaced. The water pump also has been replaced. I hope that you might give me some suggestions. This will probably go into the Guinness Book of World Records for frustration.
— Ron Rounds
A. Abnormal noises can be very difficult to diagnose, even when hearing the sound firsthand. I once entered a customer’s just-purchased new vehicle and found a note instructing me to play the included audiotape, which contained the offending sound and the customer’s narration of the accompanying road conditions. Even with this helpful assistance, it took some time to find the cause — an empty Sangria bottle entombed within a section of the rear quarter panel. Removal required breaking the bottle and vacuuming out the pieces.
Let’s try a few things that might narrow the source of your offending noise. When the chirping occurs, do you see any accompanying movement in the speedometer needle? If so, the speedometer cable is the prime suspect. Does the noise change as the Explorer accelerates, brakes or turns? If so, then it might be caused by an engine component or hose rubbing against the body.
On a straight, deserted section of road at 50 mph, slip the gearshift into neutral and shut off the engine momentarily. Does the noise continue? If so, it again may be caused by a faulty speedometer cable. If not, it’s likely caused by engine-body interference. (Be sure to restart the engine and re-select "Drive" before attempting to brake or turn.)
You mentioned the speedometer cable had been replaced. Was this an attempt to cure the noise, or for another reason? Was the new cable properly routed? If any of its bends are too tight in radius, this can contribute to cable noise and needle bounce. I’d also consider lubricating the cable shaft (if it can be removed from the sheath) with a slightly heavier lubricant.
350,000 MILES
Our current high-mileage, original-engine champ is Peary Kraft’s ’93 Ford F250 pickup with 350,000 miles. Peary believes regular maintenance is the key to the truck’s excellent service. Keep those stories coming in.
SUGGESTIONS
Reader suggestions for our trunk emergency kit: Brenda adds a pair of gloves and some wire (for securing a broken tailpipe). Ken includes a disposable camera (to record accident details), a permanent marker and paper, and a poncho. Dale suggests a pocketknife with a bottle opener and wine cork puller (might as well enjoy yourself while waiting for help to arrive). Finally, John recommends some basic tools in order to change that broken drive belt.
Brad Bergholdt teaches automotive technology at Evergreen Valley College in San Jose, Calif. E-mail him at under-the-hood@juno.com or write to him in care of Drive, Mercury News, 750 Ridder Park Drive, San Jose, Calif. 95190. He cannot make personal replies.
