High pitch noise (like a screaming girl) from the engine bay, what could it be?

[defever]

Hello knowledgeable people,

My car seems to be in a phase when things go wrong one after the other. Recent fan belts replacement, both rear suspensions, airbag warning (was just a grub on connectors under the seat), and now this one:

I was driving around all day on Sunday driving through several towns (start - stop) and through country roads and A roads (up to 70mph) and noticed a very unpleasant high pitch noise almost as unpleasant as whining little girl screaming on top of her voice.

This happened while driving through a town (start-stop) and came on randomly for around 5min. I couldn't quite figure what it was as nothing I was doing affected it (changing gears up-down between 1 and 3, breaks, hand breaks, acceleration, clutch, engine on/off, steering left / right). There was an boy-racer modified Fiesta driving right behind me so I finally assumed that it was his car not mine. I was that uncertain and the noise was really random. Drove for another couple of hours since then but no relapse.

Today I drove the car for about 1hr for the first time since Sunday and the noise came back on. I drove for 30min through country lane and town, stopped and went to a shop for about 10min, then drove again and it came on. Not as severe as on Sunday and not that long either. Just hissing high pitch in the back ground for 1min or so. Again couldn't affect the noise by my action (did all the above again with no change).

Googled a bit and there was something similar symptoms associated with turbo, "suspected" bearing, front wheel mal-tracking, uneven wear on the front tyres, and gear box differentials (?!)

I realise that I'm not helping anyone to help me by being rather vague but I just wanted to seek guidance to what I would need to look out for or what to check as process of elimination.

I don't have one but would it be worth scanning Vag-com? I was going to get a cable very soon. Perhaps if anyone is around in East Sussex, I can offer 4x cans of beer in return for your time and cable?

Thanks everyone for reading, always very helpful people here.

[zollaf]

far too vague. could be anything, stone trapped in brakes, worn out pads, turbo, sooo many things. usually people have some idea though to be able to point in a general direction, like it was from the back of the car. the thing is, it could be very dangerous yet you just drive on hoping it will go away.
cars are expensive to run, especially old ones like yours, which seems to have needed some routine maintenance you are unhappy with, and now needs a bit more. in its day it was an expensive luxury car, and still is. mine is the same, but i fix mine myself because thats what i do for a living. you will just have to give in and take it to a garage i'm afraid.

[defever]

Thank you zollaf, very truthful and for that reason I appreciate your reply.

Indeed it is an well-driven car and I don't intend to make any short cuts. It wasn't my intention to appear as if I was unhappy with my car or expecting a free / cheap solution. I was curious to see if it's something that has been experienced by fellow drivers and could guide me to the right way, rather than as you say trying my luck and continuing to drive hoping it goes away. I agree that I was too vague, and I'm sorry for being vague.

I like to know what I'm facing so before I call in a garage I wanted to ask what it could be (something I can visually check or not? something which may appear on VCDS?) or at least find out how I can best describe the symptom so that a mechanic can understand what I experienced with the car.

I'm sorry if I came across as if I was taking this forum for granted and unnecessarily posting another thread for no reason. Slap on the wrist...

[dreddfan]

As Zollaf says it's a bit vague but as he suggested the brakes it's relatively simple to check the brakes.
Jack and prop the car on stands, pop off each wheel, examine the brake system for any stones and pad condition. If there is a stone in there and it's been there for a while it'll probably have left a mark on the disk.
At least it's one possibility off the list.

[defever]

Thanks dreddfan for your 2p.

Little update. I took the car to the usual garage, they drove it around and (as half expected), they couldn't reproduce the symptom. They suggested to keep my ears open for similar noise. Bit disappointed but relieved to know that a mechanic has "checked" (how well, debatable) and doesn't seem to be something which needs immediate attention.

Yesterday, I happened to do the same journey as the one I heard this noise the first time. Jinx, the noise appeared. But very minimal, almost hissing. I usually have music / radio on but since the first episode, I've been driving with minimal background noise so I could detect this "metal ring screeching" noise instantly (I had the aircon and music on the first episode so it was LOUD).

Fortunately there was no traffic when the noise came on yesterday so I pulled to the side hoping to detect where exactly the noise was coming from. Pressed the brake a little and the noise went. Came back again few seconds later as I was going to a complete stop and braked again and the noise diminished. No noise at stationary.

So I'm immediately thinking it could be something to do with brake system. But I'm confused as to how the noise reacted instantaneously as I braked this time and not the first episode (I changed gear, applied foot break, hand break, stationary engine on/off, steering). Strange, but the noise was identical, only alot less in volume and duration.

Detection continues... Next time I have time I'll jack one side of the car and check the brake disc/pads for anything visually obvious. I'm glad I don't use the car as much as I used to, I can cope with not using a car for a while if needs be.

[zollaf]

something amiss with a brake pad then, possibly. some grit maybe on the pad ? how do you drive though, real careful, least use of brakes possible ? this can lead to glazing and squeels. sometimes a few emergency stops from 60 down to 10 (never a complete stop) can sort things out, get the brakes working and cut the glazed surface from the pad. sometimes new pads are called for though, although it could also be a stuck pad or caliper slide pin holdinjg the brakes on slightly. might be best to pull the lot apart and check and service all moving brake parts, including the not so moving bits.

[defever]

Thanks zollaf for instant comment!

I forgot to add this: Looking back at it and how it behaved yesterday, the noise is something similar to what I experienced with my previous car which had 1/4 of the disc left (!!) and it was screeching every time when the car was moving unless I do a few 1-sec hard stops. It was really bad after going around a roundabout and I always had to stay on the slow lane to get rid of it. Good times with a banger (got it sorted a week later).

I drive carefully, I anticipate what's ahead a lot and cruise or roll (without ******* off the drivers behind) whenever possible, with minimal use of breaks if not very gentle bouts of short break application (i.e. interval breaks on/off 1sec over longer distance rather than 10sec of constant application in shorter distance, if situation allows). So your suggestion is very convincing.

Get my Haynes and gloves out and see what's behind the tires. Thanks again for the advices, I feel better about it.

[dreddfan]

i've just changed out a knackered rear brake caliper on mime last night and it a relatively easy job.

13 and 15 mm spanners to remove the slide pins, copper grease for the pins and rear of the pads, length of string to hang the caliper off of a suspension spring, Wire brush to clean the crap off the caliper body (wear a face mask coz it's nasty dust)

Check the rubber pin covers for wear/holes. Mine were like swiss cheese. The front ones are available from Mintex with part number MBA 1301

If possible you should get some replacement pads and have them handy, most places will let you return unused sets of pads. Nothing worse than stripping the whole lot down then finding you need pads and having to go get them (not that's ever happened to me )

[defever]

Just a little update. I went to a quiet road and did few strong breaks and the noise disappeared. It's been two weeks and no noise since then. No difference in breaking performance.

So good news. Thanks all for your comments, I know little bit more about car now.