Mysterious noises from my Escort

"Billy H" wrote in news:438dfcc1$0$18532$ snipped-for-privacy@ptn-nntp-reader02.plus.net:

Without hearing, and/or feeling, it is hard to tell. It is hard with sometimes too. The symptoms would point to something on the right side drive train, but any loose piece of sheet metal can act like that. Loose exhaust and catalytic converter heat shields are often the culprit discovered after long periods of fixing things. I'd put an eye on the motor mounts as well, they can allow the engine to shift enough to cause vibration in otherwise quiet sheet metal. Could be a delamination in a radial tire sidewall as well, typically seen in old but not worn out tires. Can you make the noise by revving the engine with the car stopped? That will tell you a lot. If so you should be able to find it by ear. Drive down a hill and put it in neutral and/or turn the engine off (watch out for loosing power steering and brakes). Does the sound go away?

Dear Billy H:

I'd check the fuel system. Possibly a "dismounted" fuel pump, or injector lines contacting something they shouldn't. I have absolutely no confidence in this suggestion, so don't spend money investigating it.

Could you get a little more into a description of "rhythmic humming"?

David A. Smith

Huuuummmmmmmmm

-- Regards,

John Stevenson Nottingham, England.

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Dear John Stevenson:

"John Stevenson" wrote in message news: snipped-for-privacy@4ax.com...

No way!! He said a Ford Escort diesel, not a Mazda. ;>)

David A. Smith

Don't quite understand why you would only change the bearing on the one side? I always change pairs of bearings and bushes as a matter of course.

But... if you are turning left then the unsprung mass of the nearside wheel will effectively reduce more than the effective increase on the offside (because the outside bearings will already be 'loaded-up' even at rest. Load is slightly exponential rather than purely linear in cornering). The noise (if it is the bearings) would then tend to change 'more' on turning left because that side would experience the greater apparent change in Mass-loading (the centre of gravity moves to the outside of the circle and the loading on the inside of the corner goes through the greater amount of 'change').

I would start with replacing the other wheel-bearing also.

Next ... check the exhaust baffle at the bottom of the bulkhead (I think they all had this)... my daughters' car which she had before emigrating (Escort Diesel) had a small blow in the exhaust just at the baffle plate... the exhaust gases were 'hitting the baffle and acting like a little drum. Inside the car it sounded awful, outside you couldn't hear the damned thing above the noise of the engine. It got louder/faster with engine speed. (Not just road speed) . Which is yours .. engine speed or road speed dependant? If it is engine speed related .. then obviously it is highly unlikley to be anything to do with suspension/steering. Road speed dependant .. it is likely suspension/steering.

As for radial tyre sudewall delamination as a suggested cause .... highly unlikely/improbable. Such, if it were to occur, is unlikely to give the symptons you describe. I haven't heard of delamination of car tyres being a problem for c.30 years .. you would see the effects of sidewall degradation (cracking and splitting first ... so this should be a really simple visual check).

Can't quite follow the logic of a noise being a 'balance problem' ... if it was a wheel balance problem you would not just hear it but also expect to feel it at it's resonant speed. Do you?

As this is OT for this group... you can drop me a offline email if you want to discuss.

ieb-aht-klokwurx-dot-koe-ukay

BTW .. my background includes (amongst others) automotive engineering so I do have some knowledge in this area.

I'd definately start with that 'other' wheel-bearing (especially if it is a humming sound rather than a graunching or rattling). Regards

Ian

"Billy H" wrote in message news:438dfcc1$0$18532$ snipped-for-privacy@ptn-nntp-reader02.plus.net...

Apart from the turning left my Mondeo had the same symptoms, getting worse over time. Two new rear tyres = instant fix.

I would have put £20 on a wheel bearing or related bit on the front end. Particularly since the rear tyres were in decent nick. Well known Mondeo problem (so I'm told).

Steve

If its got hydraulically assisted power-steering, then sounds to me like it could be the power-steering fluid pump. Turning puts more load on it, not necessarily the same on RH and LH turns.

Around the late 80's my boss at the time had a 5 series BMW which developed a humming noise, increasing with road speed, that baffled all the technicians for over a year. Apparently, this was not an entirely uncommon fault, and sometime after this period BMW found the problem and put out a service bulletin instructing that a piece of double-sided tape should be placed between the very thin plastic trim strip at the bottom of the windscreen (outside, not inside the car) and the screen itself. The result was an instant fix, as the wind pressure/speed had been causing this to resonate against the glass.

Perhaps something similar may be occuring with a piece of external trim or engine sheilding?

Peter

"Billy H" wrote in message news:438dfcc1$0$18532$ snipped-for-privacy@ptn-nntp-reader02.plus.net...

Thanks all!!

The noise is definitely not power plant related, I base this on the fact of my running the car with the engine off, the noise is the same.

Mr Stephenson is partially correct, it is huuuummmmm but with a little huuuummmmmm HUMMMMM huuuummmmm tempo to it, i.e. it has a discernable wax and wain, althought the timing between these is imeasurable with my stopwatch!!!!

I have in mind the rear wheels, although I was certain it was the front.

I shall change the other front bearing whenever I get the opportunity, along with the second wishbone.

There is no resonance, I had a front wheel with balance problems causing a big pull to the left but cured it with a change of wheel, and the wobble now is not noticeable if there at all.

Rear wheel change seems best next course of action.

Thanks again!

"N:dlzc D:aol T:com (dlzc)" wrote in message news:LErjf.10514$dv.8256@fed1read02...

I only changed the one bearing as I was convinced the problem lay in the one side. One mechanic I spoke with is baffled. The other said it sounds from my description to be the offside bearings.

I was told to let it develop, and I may well have ot if it is not fixed by replacing wheels and bearings.

Do you have think it could be CV joint? My father says they tend to click if they need replaced, this noise is not a click, although the humming is more akin to a vibration (although the car does not shake) than to a flute or trumpet!

Regards the bearings, the wheels do not and did not wobble vertically when given the grip and push-pull procedure, they did wobble a little left right but I am told this is normal.

Dear Billy H:

Let's work on nomenclature. You are in the UK. A turn to the left will place more load on the driver-side bearings, suspension, and depress the wheel further up into its wheel well.

What side of the car is the "offside"?

Google hum "CV joint" ... only 777 hits. You could decide based on some of these if it sounds like your problem.

Sounds right.

I notice that you said elsewhere that the noise continued after the engine was turned off.

When did the noise start? Before or after correcting the wheel balance by changing the wheel?

Is the tire(s) installed identical to the ones that were on it before? I am curious if you got a different profile, and are contacting some of the bits (metal or plastic) inside the fenderwell.

How much transmission fluid is in the tranny?

Is the same noise made when going backwards, and making the same type turn (or can you not safely go that fast)?

David A. Smith

"N:dlzc D:aol T:com (dlzc)" wrote in message news:NrNjf.10661$dv.5551@fed1read02...

based on the nearside being nearest the kerb and us in UK driving on left, offside is right.

began after some work on the alternator. that had me flummoxed. but am quite sure it is not the alternator!!

don't know, need to check. makes noise when tranny disengaged.

unsafe.

Does it have electric fan? Bearings! Water pump, alternator bush, Is it overhead cam? cam belt adjusting wheel bearings? All these can make the noise you describe. Maybe noise is coming from somewhere different than you have been looking. Just coincidence turning corner seams to alter noise?

Just thinking, doesn't power steering pump squeal if low on fluid?

Lionel

Take fan belt off and do a short trip to test. Will be Ok in cold weather for a couple of miles with no water pump

This will then eliminate one area.

-- Regards,

John Stevenson Nottingham, England.

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I'll be here forever with all these little things.

I know it is not the fan belt. (He says with an air of hope in his head!!)

I adjusted the belt and it made zero difference.

Having said this do you suggest I do release the belt? I know what you say is purely scientific, but must I go to this extreme?

Electric fan yes.

Water pump, maybe ( sadness ) but later date.

Alternator bush unlikely (engine does not need to turn for sound to occur).

Cam belt adjusting wheel bearings? What do you mean? I changed the belts a couple of thousand miles ago...

Manual steering. Does power steering do that?

Dear Billy H:

...

...

Since you have turned the engine off, and teh noise persists, this is not he cause. No, you do not need to do this.

David A. Smith

Dear Billy H:

So the bearing on the side you didn't replace the bearing on is the one that *could* (not does) get louder when you turn left.

...

Is the fan electric? In some cars, this will continue to run for a bit, and you may have moved the fan shroud while you were poking around. No need to check this if the "rhythm" changes with car speed.

In a front wheel drive, disengaging the transmission simply prevents the torque converter rotation from reaching the rear wheels. There are a large number of gears that are still directly connected to the driven wheels, and turn when they do.

OK. They did it in "Hooper" (a really bad film you probably didn't see)... ;>)

Make sure the fender wells are clear around the tires. Plastic bags, cardboard, displaced fender well liner.

David A. Smith

"N:dlzc D:aol T:com (dlzc)" wrote in message news:5F5kf.10763$dv.6601@fed1read02...

Yes.

All this makes me sound *to myself* a total imbecile. I am however receptive to advice from elders and betters (and the judgement of who is *better* is down to me, and I'll always get things wrong on my own... *but sometimes they'll get it right*... life is a pain in the infundibula...).

Yes I listened to advice and changed the side I thought was okay but could've been wrong and left my adjudged side alone. (slap me now before some fool does...).

Never again shall I take paraffin on a river boat trip...