Mito whistling squealing engine noise

[Jamez]

Hi, I’m a forum newbie although I’ve owned Alfas for nearly 10 years. I’ve got a 2009 Mito 155TB Veloce (with 20k miles on the clock), really love the car but I have a mystery engine noise and I wondered if anyone else had encountered the same issue and hopefully resolved it! It sounds to me like a belt slipping or a worn bearing but I’ve had it checked twice by my local dealer but they can’t find anything wrong.

It’s a strange whistling, whirring, fluttering noise (similar to crickets at night!!) that can develop into a belt slipping style squeal, particularly if I allow the engine to labour a bit at low revs. It’s been happening for a while and I’ve made the following observations:

* Only intermittently heard.
* Happens when weather is cold and damp but can be heard even when the engine has warmed up.
* Only occurs at low parking speeds – noise disappears (or is drowned out) above 2000rpm or so.
* Noise can be reproduced if engine revs are too low (engine is allowed to labour a bit) when pulling away or reversing, for example when we had snow, driving in a ‘high gear/low revs’ style to avoid wheel spin.
* Occurs with car in gear or revving in neutral.
* Is mainly heard at the end of a short journey (4-5 miles) when engine is warmer.
* Generally is not heard when car is first started from cold apart from 2 times when car was started in freezing conditions, very loud but brief squealing noise from approx’ cam belt area of engine bay.
* Noise becomes louder under increased load like when heater fan speed increased and the headlights are on.
* A longer journey or blast in dynamic mode can sometimes clear the noise but not always.

Does this sound familiar to anyone? It’s frustrating because it’s not all the time - the engine normally sounds low and growly at low speeds (which is very nice). It’s unpleasant when it sometimes sounds more like an old transit van when parking up. Also I’m concerned it’s a developing problem that might result in an expensive repair somewhere down the line.

Any advice or ideas gladly received!

[GT_MitoOwner]

Sounds like a slipping fan belt to me..

Espically when you say it increases when you put heater and lights on

[996]

Yep get the same noise here..Always been the same tbh and does sound like the fan belt slipping slightly...
Not been of concern though as it only appears when I'm being lazy with the revs and gear changes

[wo0dy]

Have a similar problem, same model and age. Took it too dealers 3 or more times before they say they think its the alternator/belt to be at fault. They kept saying it was my tyres being noisy, so I had them changed at my cost hopefully this sorts it; ill let you know in a week or so when it's in to be sorted. Had the extended pipe fix done when the whole freezing scenario started a couple of years back. My other thought was it could be the waterpump maybe?

[Jamez]

Cheers for the replies - yeah I'm pretty sure its the fan belt slipping too, just need to convince the dealer! They insist the belts are fine and plenty tight enough. Sods law of course whenever they've looked at the car the noise stubbornly refuses to make an appearance.

[Jamez]

Wo0dy, sorry to hear you've had the same issue, although its interesting to hear the same problem on the same model/year. I'd be really interested to see if the fix works - please post an update when you know more. Water pump idea is a good one - I'm no mechanic but surely there's a bearing or impeller that might be noisy when worn?

[GT_MitoOwner]

Possibility of it being the alternator or perhaps the pulley. Some pulleys these days on alternators have little clutches in them to protect the alternators form surges in power, no idea if MITO's have them or not but mabe worth a look seen as how its apparent with load change. Might need to see a parts picture to find out....

[mitomatt]

Yep, a problem for a few of us:

http://www.alfaowner.com/Forum/alfa-...om-engine.html (Squeak from engine.)

[Stibbs]

Surely they can just take the belt off and if the noise goes away it's the belt, pulley or the tensioner

[996]

Originally Posted by Stibbs

Surely they can just take the belt off and if the noise goes away it's the belt, pulley or the tensioner

[996]

On the way home tonight in slow traffic it started again...

I've sussed out that driving at 2000 rpm in 3rd for 30 yards or so then give it some
throttle it rears it's head
Tried it several times just to make sure...

Tried the same in 2nd, 4th, 5th and 6th and not a peep ....

Doesn't do it revving/driving from 0 in 3rd either .... Only at 2000 rpm and in the above way ?

[Jamez]

Thats weird. I only notice it at low speeds, under 2000rpm in 1st & 2nd gear. I always hear it when I'm parking in the multi storey where I leave it when I am at work (alway take it up to 3rd floor to keep her well away from other cars!). Its bizarre because all last week I was plagued by the noise but today and yesterday not a peep - engine has sounded perfect. Whats that all about?

[996]

[QUOTE=Jamez;
Whats that all about?[/QUOTE]

It's an Alfa

[wo0dy]

My problem appears to be solved by a new alternator/belt/bracket. This morning the car said it was -1.5 and all good.

[ViR2]

I have the same whisling noise, but it's surely not a belt or anything... I think it's the engine

[Jamez]

Cheers Wo0dy, fingers crossed thats the problem sorted for you. I will attempt to find a helpful dealer and see if they will take a look at mine with the alternator/belt in mind. Did whoever fixed yours actually hear the noise to start with?, because my biggest problem so far is the dealer can't hear it and probably thinks I'm making it up!

[wo0dy]

It took many visits for them to hear it; was a right jobs worth! But all good now fingers crossed.

[Jamez]

Woody, which dealer did you use to replace the alternator etc? The ones I have contacted that are local to me are not filling me with much confidence, and I'm trying to avoid the repeat visit scenario. Cheers mate.

[996]

Sod's law .. Mine has decided to squeak, squirrel and squirl in 2nd, 4th and 5th between 1-2 rpm as well as in 3rd now

[wo0dy]

Sounds like gearbox 996 :-/

[996]

Originally Posted by wo0dy

Sounds like gearbox 996 :-/

Deffo sounds like a slipping belt , my gearbox makes an altogether different bum cheek
clenching sound

[Jamez]

Encouraging news, Blade in Cheltenham say they've had a Mito in with a similar problem and it turned out to be the alternator so I'm going to book the car in with them and see how it goes. The other dealer I contacted refused to comment on the symptoms and would only have the car in for a test drive. Fingers (and everything else) crossed Blade can fix it.

[wo0dy]

Originally Posted by Jamez

Encouraging news, Blade in Cheltenham say they've had a Mito in with a similar problem and it turned out to be the alternator so I'm going to book the car in with them and see how it goes. The other dealer I contacted refused to comment on the symptoms and would only have the car in for a test drive. Fingers (and everything else) crossed Blade can fix it.

who was the other dealer?

[Jamez]

Quick update to this very old post - I decided not to do anything about the squealing whistling noise as it went away with the (relatively!) milder weather last summer, but sure enough it came back with a vengeance this winter. Couldn't take it to the Cheltenham dealer in the end as it no longer exists, so booked in with Johnsons in Solihull and they decided it was a worn aux belt and a failed battery (wasn't holding much above 50% charge when they tested it). So they fittted a new battery and replaced the belt (they also checked the tensioner which was ok) and although its early days, so far so good - the noise seems to have disappeared. Fingers cross it stays that way! Johnsons were very good by the way - they genuinely wanted to solve the issue and took on board all my ramblings about the symptoms. Didn't charge the earth either.