jawns
New Member
- Joined
- December 25, 2011
- Messages
- 3
- Reaction score
- 0
- City, State
- Richmond VA
- Year, Model & Trim Level
- 1998 Explorer XLT
Hello Explorers,
My daughter has a 1998 Explorer XLT 4wd AT V6 SOHC, purchased in 2005 with 120K miles, that I maintain as my skills allow. I've put brakes, shocks, filters, plugs, etc. on it and it has been a reliable vehicle.
She reported that it had developed a strange noise last night at the end of a 2 hour road trip. She said that it made a loud noise when the accelerator was released after reaching 50 mph and that the noise disappeared if you got back on the gas.
I was at her house for Christmas this AM and after lunch installed one of my gifts for her (new hood support cylinders) on the truck and then took it for a diagnostic drive.
Sure enough, got up to 50 mph, released throttle, and a fairly loud noise seemed to be coming from the dashboard or floor area and stopped when throttle was pressed again. We made it repeat the noise several times and turned into a parking lot and put it in Park. My first thought was speedometer cable or speedometer because I drive a Ford truck on my job that has a screeching speedometer, so I was going to try to disconnect the cable. I didn't have a flashlight or tools and quickly knew that it would be futile.
When I shifted from Park to Reverse, the noise started and I engaged the parking brake and got out of the truck to try to locate the source. It is not coming from inside the exhaust pipe. It is loudest in the area from the radiator to the rear of the front seats. It may be louder on the driver's side, but not by much. When the hood is raised, the noise seems to be coming from below near the firewall. I tried repeatedly but could not make the noise start again without getting the vehicle up to speed.
The noise is difficult to describe but I'll try: it's a mixture of a buzz and a whir/whine; there's a slight lag between throttle release and the beginning of the noise; it's a mid-range pitch that stays constant in volume and pitch until it stops at about 10mph or when you press the gas; it seems rotational in some ways but doesn't change as the vehicle slows or when the brakes are applied; it's about the same volume inside the cab and out; the noise is loud enough that it can't be ignored but not overwhelming. It sounds like releasing the throttle starts something spinning and it continues at a constant speed until you get on the throttle again.
My gut tells me that the high vacuum under deceleration is engaging something or causing an effect like blowing a trumpet mouthpiece and the only thing that stops it is to decrease the vacuum by opening the throttle.
Has anyone experienced or heard of anything similar to this? I've heard lots of vehicle noises, but this a new one for me. I really don't think it's coming from the drivetrain because there's no effect on the way the truck drives or feels (no vibration).
Any input will be welcomed--I'm going to drive it more tomorrow and look for more clues.
Doug J
My daughter has a 1998 Explorer XLT 4wd AT V6 SOHC, purchased in 2005 with 120K miles, that I maintain as my skills allow. I've put brakes, shocks, filters, plugs, etc. on it and it has been a reliable vehicle.
She reported that it had developed a strange noise last night at the end of a 2 hour road trip. She said that it made a loud noise when the accelerator was released after reaching 50 mph and that the noise disappeared if you got back on the gas.
I was at her house for Christmas this AM and after lunch installed one of my gifts for her (new hood support cylinders) on the truck and then took it for a diagnostic drive.
Sure enough, got up to 50 mph, released throttle, and a fairly loud noise seemed to be coming from the dashboard or floor area and stopped when throttle was pressed again. We made it repeat the noise several times and turned into a parking lot and put it in Park. My first thought was speedometer cable or speedometer because I drive a Ford truck on my job that has a screeching speedometer, so I was going to try to disconnect the cable. I didn't have a flashlight or tools and quickly knew that it would be futile.
When I shifted from Park to Reverse, the noise started and I engaged the parking brake and got out of the truck to try to locate the source. It is not coming from inside the exhaust pipe. It is loudest in the area from the radiator to the rear of the front seats. It may be louder on the driver's side, but not by much. When the hood is raised, the noise seems to be coming from below near the firewall. I tried repeatedly but could not make the noise start again without getting the vehicle up to speed.
The noise is difficult to describe but I'll try: it's a mixture of a buzz and a whir/whine; there's a slight lag between throttle release and the beginning of the noise; it's a mid-range pitch that stays constant in volume and pitch until it stops at about 10mph or when you press the gas; it seems rotational in some ways but doesn't change as the vehicle slows or when the brakes are applied; it's about the same volume inside the cab and out; the noise is loud enough that it can't be ignored but not overwhelming. It sounds like releasing the throttle starts something spinning and it continues at a constant speed until you get on the throttle again.
My gut tells me that the high vacuum under deceleration is engaging something or causing an effect like blowing a trumpet mouthpiece and the only thing that stops it is to decrease the vacuum by opening the throttle.
Has anyone experienced or heard of anything similar to this? I've heard lots of vehicle noises, but this a new one for me. I really don't think it's coming from the drivetrain because there's no effect on the way the truck drives or feels (no vibration).
Any input will be welcomed--I'm going to drive it more tomorrow and look for more clues.
Doug J
