1997 Ford Explorer 6 cyl Four Wheel Drive Automatic 138000 miles
Hi, I've got a 97 Ford Explorer, Automatic, 4.0L V6, 4x4. I've recently began hearing two noises that seem to be coming from the front end. I don't know if there related or independant of each other. They didn't start at the same time and don't happen at the same time so I'm guessing their individual problems.
The first sound is a thumping sound when driving down the road. It's hard to say which side it is coming from. I checked the tires and I don't see any knots or visual sign of damage to the tires. They are the original tires on the truck and still have a lot of tread. The paperwork in the glove box when I got the truck showed the tires were balanced when they were put on. This Explorer has had new shocks, inner & outer tie rods, upper control arms w/ball joints, lower ball joints, and new sway bar bushings and end links with bushings put on within the last 6 months. The majority of the front end parts have been replaced so I'm not sure what is causing this thump sound. It only occurs when moving. Something important also is that I don't really " feel" the thump in the steering wheel. It could just be so minor that I don't notice it on road surfaces that aren't perfect and most SUV's don't ride like a car does.
Is it possible it could be wheel bearings? Could a tire have gotten out of balance already? I thought the bearings made the grinding, squeeling, or whirling sound. I never had one cause a thump before. I've checked the new parts that have been put on recently and all still seems well.
The other sound is a rattle noise. It occurs mostly when I hit bumps, but it does happen when sitting still at an idle also if the endine has a moment it doesn't run at a perfect idle all the time. It is a metal sound. I was thinking the exhaust because I recently had a new muffler put on, but upon visual inspection I can not see any loose parts. The metal sound also sounds like it is a really thin piece of steel, kind of like a dust shield for brakes. I checked that out and they weren't loose so I don't know.
I apologise for the long post, but I want to be as thorough as possible. Any thoughts on this thumping sound when moving?
Hi Steadyhand. Welcome to the forum. It sounds like you did a thorough job of looking for these problems so how about trying a different approach? There is a tool called a " Chassis Ear" that consists of six microphones you clip on to suspect areas, then drive while listening to a receiver in the truck. The new version uses four wireless microphones and two wired and has a speaker in the receiver. The older version uses six with wires and has headphones. Both have switches to select between the microphones. When you find the loudest one, you can move the microphones around until you zero in on the source of the noise.
I'm trying to buy one of these tools right now. As I recall from years ago, they cost around $100.00. They are available from the guys in the tool trucks such as Mac, Matco, Cornwell, and Snapon. You might find one for rent at the auto parts stores but a lot of people, including mechanics, have never heard of it. It was a standard piece of equipment at the Chrysler dealership where I worked. As a suspension and alignment specialist, I used this tool quite often when looking for rattles that would only show up when driving on rough roads.
May, 5, 2010 AT 3:12 PM
Unfortunately I have not found this tool locally. However, after rechecking everything yet again I did find the two camber bolts that hold the upper control arm for the front passenger side were kind of loose. I don't know if the mechanic that did the alignment didn't tighten them down or if they worked loose from the up& down motion from driving.
The left side of the arm that should have been held tight by the bolt appeared to be slid all the way out, toward the outside edge of the truck. The right side was slid all the way back towards the engine.
Is it possible the alignment was thrown off and is causing the thumping noise? I've had alignment problems cause a pulling to one side but never had one cause thumping.
I noticed something else. The thumping noise is very minimal, if at all, when backing up. You hear it very loud when going forward. What could this mean?
May, 5, 2010 AT 10:46 PM
Loose bolts are never a good thing. What does the tire wear look like? If the camber changed it will cause the toe to change too. You should have noticed a crooked steering wheel as a result, and both front tires should show toe wear. I suppose a tire could track to the side and walk back. That could make a thump but I'm sure you would have felt it in the steering wheel.
As for the Chassis Ear, it is a standard piece of equipment at Chrysler dealerships, but even a lot of mechanics there don't know what it is. I finally found it on the Mac Tools web site. Here's the web address:
It's listed under "Diagnostic and Testing", "Audio Diagnostic Units", then about half way down on the second page, it's model number ET6600. Sorry to say it costs twice what I remember at $199.99. A little further is the wireless model number ET97200.