My alternator belt started squealing on first starting a few months ago, only on wet mornings. It's since gradually got squealier, to the point now that it squeals constantly until the engine is hot when it usually gets dry enough to grip.

I've had a look under the bonnet but it looks to be in a very enclosed location. I have found the correct part number for a replacement belt, but haven't ordered it yet.

Is this a garage or DIY job? (for someone with common sense, but not much car repair experience) I've had a hunt around the forum, but can only find info on replacing the alternator itself.

Other questions...

Should the belt be replaced instead of tightened? I would guess so, as squealing means stretching therefore weakening.

Is replacing the belt more involved than tightening the existing one?

Is this likely to be a symptom of a more serious problem, i.e. the alternator stiffening up before failing?

Thanks all as ever...

P.S. It's a 150BHP 1.9 Diesel. I think the part no for the belt is 6PK1413.

Its usually worth fitting the tensioner as well, if you shred the belt it can take out the cam belt. Also check that the power steering and alternator are not putting too much load on it.

Get your battery tested.

Dave.

I'm currently going at this from Davren's tip, and attempting to get a new battery.

I took it to a local garage who tested it. It was a borderline pass on his tester, but the bubble on the battery is showing as black instead of green. He wanted £90 for a new one, which I thought sounded a bit steep. His was a cheapie-grade battery.

I'm currently trying a find a new one elsewhere, but (guess what, Croma owners), it's a weird size. Halfords say they have one, but theirs is tiny. Euro Car Parts sold me one according to their info, but it was about 4cm too short and only 72Ah, so I got a refund. I need to pull mine out to measure it properly and get the info off it, but I can see a "9" on it, which is probably the beginning of 90Ah.

90Ah - 450A or 440 cold crank power (from eLearn for cars with Alarm fitted otherwise 70Ah)

No dimensions given.

For Halfords stuff see if you can find anybody with a trade card. Big discounts on certain maintenace products. e.g. just this weekend paid only £45 for an £80 battery 4 year warranty Calcium battery. Bulbs also another bargain area with something like 50p for a headlamp bulb.

Having just been through this dilemma (someone swapped the battery on my car for a smaller one before I got it, and I didn't realise until it was too late - don't you just love Fiat main dealers :bang I also discovered the weird size.

In the end I settled for an 80AH battery which turns my 2.4 JTD over just fine. Battery dimensions are standardised in the aftermarket world, in this case I fitted a code "110" battery which is spot on for length and width but just slightly too low - I fitted two 10mm strips of wood below the clamp and all was well.

HTH.

It's good to know that a 110 will fit in if necessary. Is that the 278mm one? If so that's the one that I know was about 3-4cm too short. I'll pull it out and have a proper look later.

I'm sure the 90Ah requirement must be over-design. Googling for 90Ah finds lots of motor home batteries, i.e. fridge, lighting etc.

90Ah @ 12V = 1.08kWh

Dimensions are 317 x 175 x 190, it fills the battery bay but is slightly lower than the original. If you search for "110 80AH Battery" you should get some results.

Out of interest, my 2.4 was fitted with a 65AH battery for 18 months with no problems other than a slightly slow cold cranking speed. Batteries only seem to last four or five years with modern car electronics. You may still have to re-tension your belt but changing your battery should help in the meantime and certainly won't do any harm - see what happens I suppose. Please let us know how you get on...

HTH.

I reckon your battery is actually the right size (physically at least).

I've just measured mine - I didn't remove it but measured the lid. There is enough space to pop the tape measure down the side to get the height. According to my measurements it is L310 W170 H190. There's about 1cm of space at the end of it.

I did notice that there are two bolts sticking through the clamp bar that holds it in place. I thought they looked like clamps for the battery, but they are about 1cm clear of it. In fact, they are for the plastic cover clips. The bar only holds the battery down at its ends. Imagining the battery as a person, it is clamped down by its shoulders, not its head!

I was just wondering if this is why you thought yours was too low?

The numbers from the battery label are:

MAGNETI MARELLI
12V 90Ah 440A
542440-STS

Another smaller label says:

Dis. FIAT: 46840940

I'll see what I can find out...

P.S. I won't be ranting at anyone if it doesn't cure the squeal, as I have now found out that the battery's on its way out so needs replacing anyway. If the squeal goes then it's a bonus.

Doofer said:

The bar only holds the battery down at its ends. Imagining the battery as a person, it is clamped down by its shoulders, not its head!

I was just wondering if this is why you thought yours was too low?

Click to expand...

Agreed, but with the battery I fitted the clamp bar didn't come down far enough to contact the 'shoulders' - thanks for the thought though. Look forward to hearing how you get on - it's at this point I find out that Fiat charge less than everyone else for batteries

I will give Fiat a try, for the sake of a phone call. Otherwise a 110-type battery looks good enough. I have found an Exide Xtra Plus which is 85Ah, and also a Varta silver one that's 85Ah. The Xtra Plus is 190mm tall, but is being replaced by the Premium, which is 175mm tall. Not sure whether to get the older model (better fit but old stock). The Varta is also 175mm tall.

I've ordered a Bosch S50 100. It's 315x175x175, so will need a bit of something under the clamp to make it tall enough. Being from the posh silver range, this has 85Ah, so near enough to the spec. Blurb here...

http://www.boschautoparts.co.uk/pcBatt9.asp?c=2&d=1

Brochure...
http://www.boschautoparts.co.uk/pdf/Product_program_S5[1].pdf
(manually copy and paste link above)

I'm very sure that Varta and Bosch are the same company. Varta Silver F18 = Bosch S50100. Both have a 5-year warranty, so I wanted to buy locally so I can return it if it packs in before the car does. Eventually ordered it from a local branch of Euro Car Parts for £86.89 inc VAT, so a very good deal.

I decided not to bother calling Fiat, as it's bound to be expensive and the original one has failed just after three years so I don't want another anyway.

The Bosch battery was ordered incorrectly from Euro Car Parts. I asked for a Bosch part no S50100, they ordered an S5, in UK size 100, which is a Bosch S50070. They wanted £100 for the correct part.

In the end I got a Varta F18, which is identical to the Bosch one I wanted to order. I got it from www.national.co.uk, which was the cheapest I could get on for locally, at £95 after getting 10% discount for ordering online. This price actually included fitting, but I decided to take it and fit it myself.

It starts a bit more eagerly, and the headlights don't go dim when the revs drop any more. However, the belt still squeals after starting the engine on a damp morning.

So, back to the original question... Does anyone know what's involved in tightening the alternator belt? I have seen the other thread about changing the alternator, but I was hoping an adjustment might be a bit simpler. I can see the belt, but access looks a little tricky.

By the way, the belt doesn't seem particularly slack. I'm wondering whether the real problem is that the alternator is stiffening up. I hope not, but a slight tightening must be worth a try first.

The auxiliary belt tensioner has been known to fail. The tensioner bearing fails and the tensioner leans over a few degrees, which might be visible from the top. Also, does it stop the noise if you turn off the air con?

This might be a bit of a 'chicken and egg' scenario - belt slips, wears/polishes the bearing faces, belt more likely to slip and so on. If it's happening on damp mornings then I'd suggest lack of friction is the problem. For a permanent fix you may have to replace the belt.

Keith is correct about the tensioner, it's a problem shared with the 2.4 but the design is different. According to Elearn you have a sprung tensioner with no adjustment possible, so your options are limited. If the belt has stretched then replacement is required.

One last long shot - is it the belt squealing or the bearings in the tensioner?

Thanks for the help from the both of you.

The air con is permanently off at th.e moment. I did spray a small amount of furniture polish on the belt. This obviously didn't stop it slipping, but did allow it to slip silently for a day or two. It probably wasn't a good idea in hindsight, but my logic was to get rid of the slipping noise so I could check that it was the belt making the noise. I can confirm that it was completely silent after a quick squirt, even though everything was still turning OK.

I can reach the belt, and it feels pretty rigid.

I have read something about spraying talc on it. Good idea or bad?

I'll have a play tomorrow and see what happens. Is any part of it accessible without removing the wheel and inner wing?

Doofer said:

I have read something about spraying talc on it. Good idea or bad?

I'll have a play tomorrow and see what happens. Is any part of it accessible without removing the wheel and inner wing?

Click to expand...

Talc is good for removing contaminants. One to try (which might seem counter-intuitive) is WD40 - it actally softens the rubber rather than lubricating as you might think.

You'll have to take the wheel and inner wing panel off to get to the tensioner - I'm not familiar with the 1.9 so don't know what access you can get from above - sorry.

HTH.

Talking of belt noise.

When I have had a squeeling belt which I cannot immediately identify (eg. alternator, fan etc. on multiple belt cars) I gently and accurately sprayed each belt with Holts Wet Start. This quickly quiets the offending belt / pulley. I also a little less agressive/oily then WD40.

Only a small mist is required for quick results.

Doofer said:

My alternator belt started squealing on first starting a few months ago, only on wet mornings. It's since gradually got squealier, to the point now that it squeals constantly until the engine is hot when it usually gets dry enough to grip.

I've had a look under the bonnet but it looks to be in a very enclosed location. I have found the correct part number for a replacement belt, but haven't ordered it yet.

Is this a garage or DIY job? (for someone with common sense, but not much car repair experience) I've had a hunt around the forum, but can only find info on replacing the alternator itself.

Other questions...

Should the belt be replaced instead of tightened? I would guess so, as squealing means stretching therefore weakening.

Is replacing the belt more involved than tightening the existing one?

Is this likely to be a symptom of a more serious problem, i.e. the alternator stiffening up before failing?

Thanks all as ever...

P.S. It's a 150BHP 1.9 Diesel. I think the part no for the belt is 6PK1413.

Click to expand...

Hi there! Its a bit late I know but here goes. Remember how the old single V pulleys used to wear and develop a dog-leg? (I've re-machined one or two pulleys because of this) Anyhow that dog-leg stops the belt from gripping properly. Polyvee pulleys can also wear but this is not so easy to see. I would say that if the vees of the pulley have a sharp top the pulley is worn. I have re-machined this type of pulley as well and I once converted a Ford 4 groove pulley into a 5 groove pulley for a Rover 800 - worked a treat! As to whether pulley changing is a DIY job, it depends on how good you are at DIY and what tools you have. Highly recommended is a 12 volt impact wrench (the type made so that petite ladies can undo wheel nuts) target price £20 or less. If you cannot get access to an impact wrench the alternator may need to be stripped so that the rotor can be held in a vice. OK there is usually a hole in the end of the alternator shaft to take a hexagon key but the Allen key and ring spanner method seldom works as often the nut is badly rusted or is too tight. Avoid garages if you can as very few of them have proper engineering skills these days. In particular main dealers are often the worst of all. As to the pulleys, the large ones seldom wear it is always the alternator pulley. Some atrocious designs only wrap the belt around the pulley by about 90 degrees which is ridiculous. In such cases one can expect to change belt and pulley fairly frequently as that tiny pulley has to transmit a couple of horsepower through a rather small contact patch.