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Insane engine noise

At least I THINK its an engine noise! I have a 2007 Ford Focus. She’s a lovely car; the first I’ve owned entirely on my own (I’m 64), with a moon roof and stick shift, and she’s red. Since she has front wheel drive I’m not really sure where the noise is coming from. I’ve had a mechanic look at her, but he has not had the time to take her on the freeway, and she doesn’t make the noise at low speeds.
The story is this: When I got the car in October it was very quiet running. New brakes, complete overhaul, about 50K miles, new tires. It was love at first sight. Some engine noise started to develop in late winter and someone told me it was the belt so I had that replaced. The noise was gone at low speeds, but once I got over 50mph it was back and has gotten louder and louder. Now its so loud it drowns out my singing, which is probably a good thing, but still worrisome.The mechanic said at first he thought it was the air conditioner belt but I havent used it or the heater in a month. Then he said he had the same noise in his truck and it had been there for awhile and was not a problem, so he would get to my car when he could and not to worry about it. The noise keeps getting louder. I AM worried about it!

It sounds like a sewing machine on steroids. Like someone has the pedal to the metal on a Singer. It also throbs at times like a cat purring. There is a small range of speed where the noise is less, but thats about 55-58mph and it never goes away at speed. Other than that it’s really loud. And about a “G” on the music scale. I do a lot of highway driving every day and I’m afraid I"m damaging my car. Any suggestions? Any help?

Maybe buy a cheap automotive stethoscope and probe around to see where it actually emanates from. This would work:
http://www.harborfreight.com/mechanics-stethoscope-41966.html

It would just be a guess as to what it may be without seeing it for ourselves.

You probably have a wheel bearing going bad. Any decent chassis shop should be able to find this within minutes.

Will it make the noise standing still, the car in PARK, and you slowly increase engine RPM to mimic high-speed driving…Or does the car have to be moving for the noise to occur??

The car has to be moving to hear the noise, and only at speed.

Ah, in that case forget the stethoscope unless you can run fast.

Thanks, RemcoW. Since I’m over 60 and somewhat gimpy, I doubt I could keep up!

I would have the wheel bearings and CV joints checked. Check the brakes while you are at it, even though they were “overhauled”…

+1 with mark and caddy. That’s a very good place to start.

I was under the impression the noise was always there, whether it was moving or not. If your mechanic can’t find a bad wheel bearing of CV joint, you may not want him to be your mechanic, though. Those are very common problems.

Thank you all for your help. I’ll get her into the shop right away.

I would be looking at the plastic “skid plate” or what ever that thing is called, especially if the noise started up right after an oil change. If there is a loose bolt, or torn out bolt hole, this thing will vibrate when the “wind” under the car is at the right speed. If you have a plastic spoiler, check it also.

Also check the plastic inner fenders and for any access flaps on those inner fenders. A loose or broken grill can also contribute noise.

Thanks for all our comments. Took the car in today and it turns out its the TIRES. The mechanic said they were badly “chopped”. When I asked he showed me. The inside edge was worn on all 4 tires, and when I ran my hand over that edge, it was ripply. Up, down, up, down, like waves. He said it MIGHT have been caused by the fact that the front wheel drive Focus is so light in the back end that it bounces a bit on the road, or it might be all the flippin’ construction and pot holes in Buffalo! Anyway, I’m getting new tires.
Oh, and to top it off, when I got home there was a nail in one of the tires!

If this noise continues when you are coasting at speed (with the transmission in neutral) then it has to be something to do with something between the tires and the output stage of the transmission. If so, then the frequency of the noise should increase w/speed. Does it? Think positive and hope it is one of the tires. Can you tell the general direction the noise is coming from? If so, take a close look at that tire and see if you see any defect in the rubber or inflation problem. If not, then the next most likely thing (if the noise is coming from the front) is the wheel bearing or the CV joint. Your car is about the right age for a CV joint, so unless you’ve hit some big potholes, I’m guessing something in the CV joint is amiss. It might just be the CV rubber boot that has split.

First things first. Ask your mechanic to put your car on the lift and check all four of the CV boots and the four tires.

You said the tires were new in October and now all 4 are badly chopped? It sounds like you have a suspension or alignment problem. Don’t just assume that getting 4 news tires will fix everything, because in another 9 months your new tires will be badly chopped again. You may need new struts and/or a 4- wheel alignment.

He said it MIGHT have been caused by the fact that the front wheel drive Focus is so light in the back end that it bounces a bit on the road

@meeksa
Boooogus alert!!! This explanation makes no sense. If that were true, then every front wheel drive Focus on the planet would ruin all four tires every six to eight months, and I’m sure somebody would have noticed that (and Focus sales would have plummeted).

Jesmed has pointed out the more plausible explanation. The condition you described, that your tires are “chopped” sounds like what I’ve heard called “cupped”. One reason tires get cupped is that they bounce, even imperceptibly, as you drive (so your mechanic may have been partly right). This can be the result of such things as tires being out of balance, or having worn shocks or struts. There are probably other causes too. Once cupping has been started, it’s unlikely to be overcome. A cupped tire will make some road noise at higher speeds, so I imagine four cupped tires would create quite a symphony.

It’s odd that all four tires have the same defect. One tire could lose a balance weight, or one or two struts could be bad, but having the problem at all four wheels is puzzling. So as Jesmed implies, the chopped or cupped tires are a sign of some other problem, which if not resolved, will just continue destroying tires. I think he’s right, that it’s something in the suspension or alignment, or maybe the car had been in an accident before you got it and the frame is bent (unlikely, but possible). I suggest you see if you can find an independent shop that specializes in alignment and suspension, and avoid the national chain stores. Chances are good they will find your problem very quickly and solve it properly. If you find such a shop, be sure to give them good referrals, including on the Mechanics Files on this website.

Good luck!
–Roadtripper