I have a 2003 ford escape (V6 Limited/Automatic) that just hit the 145,000 mile mark. With routine maintenance and minor repairs, I am hoping to make the car last at least 200,000 miles. I currently have an annoying, intermittent problem that I have not been able to solve on my own, so I am hoping someone can shed some light on this for or point me in a different direction. The car has no performance issues, but when the vehicle come to a stop while in drive (at a red light, etc) the car make a low humming noise that is coming from the front of the vehicle. The noise stops once I get the vehicle back in motion or when I throw the car into neutral. The humming also changes when I turn the steering wheel, but I think that might have to do with the load on the engine changing. The only thought I have is the torque converter, but I am not sure how I would test or rule that out. Any help or suggestions is greatly appreciated. Thanks!
Before you go to any extreme measures, have the car put up on a lift and checked for a loose or bent heat shield on the exhaust system. These thin sheet metal parts can produce a variety of noises under specific circumstances (e.g.–only at certain RPMs, only when the transmission is in gear, only at certain ambient temperatures, etc.), and can frequently be fixed by using a large screw-type clamp in the right place.
Among the noises that a loose or bent heat shield can produce are sounds that can be described as…buzzing…grinding…rattling, so hopefully your “hum” is just a symptom of a loose/bent heat shield. If this turns out to be a blind alley, then I would suggest a visit to an independent transmission shop. DO NOT go to AAMCO, Lee Myles, Cottman, Mr. Transmission, or any other chain operation unless you want to be sold a rebuilt transmission–whether you actually need one or not.
Along with that^ very solid advice, you may want to get yourself an automotive stethoscope (harbor freight, advance auto, pepboys, etc) and probe around to see where it is coming from.
Could just be a belt or automatic tensioner. The stethoscope would help isolate where the noise is coming from.
Thanks for the advice- I will look into all of these suggestions as soon as I can. I also wanted to mention that the past 2 years have included a lot of driving in the city with slow traffic and idle time. That’s another reason I was thinking the torque converter, but I will certainly double check the easy items first.
I bought a stethoscope and went under the vehicle tonight, and I was able to rule out the heat shield, exhaust, and tensioner as the culprit. I put the stethoscope on the torque converter and transmission housing and there was no sign of the noise. To my surprise, I think the noise is actually coming from the power steering system. Would a bad steering gear, rack and pinion, or pump cause this kind of intermittent humming? The noise is also extremely pronounced within the vehicle if I turn the wheel all the way to either side.
The problem might be with the Idle Air Control valve. There have been reports that the IAC valve can make a humming noise at the front of the vehicle on Fords at idle.
Now that you have a stethoscope, when the engine is idling and the humming noise occurs place the tip of the stethoscope on the IAC valve. That’ll confirm if that’s where noise is coming from.
Tester
Hi tester, thank you for the suggestion. I actually recently replaced the IAC valve as a part of my last major maintenance, and I actually did listen to its function with the scope just to make sure. The sound does not seem to be related to the IAC valve.
I was thinking the power steering pump when you mentioned the noise changed while making steering changes. I guess you have already made sure the fluid level is where it should be.
Does anyone have suggestions as to how I could differentiate between a bad steering gear and a bad power steering pump? The noise I am hearing changes when I engage/disengage any of the mechanical items that run off the drive belt. For instance, when I turn off the headlights or the a/c, the noise will change and then come back. Perhaps I am hearing the sound at idle as the rpms drop and don’t spin the power steering pump fast enough to compensate for a malfunction? Still shooting in the dark. Thanks again for any suggestions.