MK6 2.4 DI - Belt Riding Up Alternator Pulley / Squealing.

[Mr_Moo]

Hi there.

Long time lurker, first time poster.

I have a 2005 Ford Transit MK6 2.4 DI Duratorq RWD and I am dealing with a persistent belt issue. The problem started a few months ago after a friend replaced the belt and tensioner for maintenance. Immediately after, the belt started squealing and I noticed a slight knocking sound. The belt began riding up onto the rim of the alternator pulley.

On a long trip shortly after, the belt partially shredded and came off. This caused the dashboard to light up, and I lost power steering and brakes while the engine temperature shot up. We put the belt back on to get home, where a mechanic suggested the power steering pump was causing the knocking. I replaced the power steering pump and the knocking stopped, but the squeal remained.

The belt recently shredded completely for a second time while driving. I installed a new belt and checked the tensioner. We found the tensioner body was 3mm out of square, so I exchanged it for another new one which has about a 0.5mm variance. After a 6-mile test drive with this new setup, the squeal became constant and the belt is again riding up onto the front rim of the alternator pulley.

The alternator pulley was scorching hot to the touch after the drive, while all other pulleys remained cool. On two occasions during the drive, the squeal stopped entirely for about 30 seconds before returning. I tested the alternator overrun pulley by locking the internal fins with a screwdriver. It locks in one direction, but the free direction feels very heavy. I can also see a very slight, but visible wobble and run-out on the pulley when spinning it by hand. It does not appear to spin square on the shaft.

What are your thoughts, please?

[DanMK7uk]

Time for a new OAP pulley or complete alternator by the sounds of it.

Is the crank pulley all ok ?

[Mr_Moo]

Thank you for the reply, Dan.

How would I go about testing the crank pulley?

[DanMK7uk]

Get under and look to see it it’s wobbling about / making any unusual noises and if fitted the harmonic balancer which is the rubbery inner part is not worn or split. Worth a check too.

[Mr_Moo]

No wobble. No noise. The squeal is 95% coming from the right (or left) hand side, towards the alternator.

I drew a chalk line on the crank pulley and ran the engine for a few mins, it's perfectly inline.

[DanMK7uk]

No wobble. No noise. The squeal is 95% coming from the right (or left) hand side, towards the alternator.

I drew a chalk line on the crank pulley and ran the engine for a few mins, it's perfectly inline.

Cool. Shouldn’t be that then.. sounds like alternator bearing then..

[knobby1]

Get under and look to see it it’s wobbling about / making any unusual noises and if fitted the harmonic balancer which is the rubbery inner part is not worn or split. Worth a check too.

Mk6 pulley is essentially solid...it's the Mk7 pulley's that fall apart.

Lord Knobrot (Smithy)

[Mr_Moo]

Thank you all.

I swapped the crank pulley for a Corteco, in an Aires in Belgium. Put on a fresh Contitech/Continental belt. No squealing... Phew, I've finally fixed it!

Onwards to Holland. 50-80 miles down the road, and I start to hear faint shimmers of squealing. Probably PTSD from the thorn in my side since January.

A few more miles down the road, and the squealing returns. I pull over. Check the belt, and thankfully, it's no longer riding up the side of the alternator pulley. No obvious signs of rubbing anywhere. Panic over, I just have to deal with the noise and pray it gets me around the Netherlands and home again.

At a friend's house while in Holland, I checked everything more thoroughly. Everything looks fine. Crank lines up with the alternator, alternator lines up with the PAS pulley, crank lines up with PAS. The belt is sitting at a slight angle on the tensioner (this is my 2nd brand new INA tensioner in a few months. The previous new one had a few mm difference on it). The tensioner doesn't really line up with anything. There's a little difference when putting a spirit level across either the crank, alternator or PAS.

The tensioner is INA.

To conclude:

Swapped the tensioner twice. It's spring loaded.
Crank swapped out for Corteco.
PAS pulley and body swapped out.
Alternator swapped out for a Hella 110amp.
New belt for the 2nd time.

I suspect I have an alignment issue somewhere. Screwdriver test on the alternator locks one way and spins the other.

I've ordered a new belt for collection tomorrow. I'm going to take off the tensioner, thoroughly clean behind it with brake cleaner, clean the bolt hole. Test the bolt is straight. Clean all the pulley with brake cleaner, since there's black belt dust on them all. Last resort is taking the crank off and on again.

Any advice on what you think might be causing the issue? I can't see any oil/grease on the belt anywhere. Checked dozens of times.

Thank you in advance.

[knobby1]

Thank you all.

I swapped the crank pulley for a Corteco, in an Aires in Belgium. Put on a fresh Contitech/Continental belt. No squealing... Phew, I've finally fixed it!

Onwards to Holland. 50-80 miles down the road, and I start to hear faint shimmers of squealing. Probably PTSD from the thorn in my side since January.

A few more miles down the road, and the squealing returns. I pull over. Check the belt, and thankfully, it's no longer riding up the side of the alternator pulley. No obvious signs of rubbing anywhere. Panic over, I just have to deal with the noise and pray it gets me around the Netherlands and home again.

At a friend's house while in Holland, I checked everything more thoroughly. Everything looks fine. Crank lines up with the alternator, alternator lines up with the PAS pulley, crank lines up with PAS. The belt is sitting at a slight angle on the tensioner (this is my 2nd brand new INA tensioner in a few months. The previous new one had a few mm difference on it). The tensioner doesn't really line up with anything. There's a little difference when putting a spirit level across either the crank, alternator or PAS.

The tensioner is INA.

To conclude:

Swapped the tensioner twice. It's spring loaded.
Crank swapped out for Corteco.
PAS pulley and body swapped out.
Alternator swapped out for a Hella 110amp.
New belt for the 2nd time.

I suspect I have an alignment issue somewhere. Screwdriver test on the alternator locks one way and spins the other.

I've ordered a new belt for collection tomorrow. I'm going to take off the tensioner, thoroughly clean behind it with brake cleaner, clean the bolt hole. Test the bolt is straight. Clean all the pulley with brake cleaner, since there's black belt dust on them all. Last resort is taking the crank off and on again.

Any advice on what you think might be causing the issue? I can't see any oil/grease on the belt anywhere. Checked dozens of times.

Thank you in advance.

Has the timing chain cover been off recently..??

Lord Knobrot (Smithy)

[Mr_Moo]

Not at all.

It sounds like it's coming from the tensioner/alternator area. Without a close field microphone, I couldn't pinpoint it.

[knobby1]

Not at all.

It sounds like it's coming from the tensioner/alternator area. Without a close field microphone, I couldn't pinpoint it.

How's the little top idler pulley..?? The bearings in them don't last forever.

Lord Knobrot (Smithy)

[Mr_Moo]

How's the little top idler pulley..?? The bearings in them don't last forever.

Lord Knobrot (Smithy)

I checked the idler. Looked OK. Span around with ease. Held firm when I wiggled it side to side. I took it off anyway, gave it a good de-gunking and derusting, of 20 years of grime.

I removed the INA tensioner, gave the engine block where it sits a good wire brush and wire wool. Sprayed a load of brake cleaner around it as well while cleaning. Put that back on, and it seemed to line up with everything. I got the spirit level out as a straight edge, and it lines up perfectly with the other pulleys now. The bolt came off very easily, so wondering whether it was a combo of some crap behind it and not tight enough. It didn't move or wobble with the belt on, though.

I also took the crank off. Gave it another scrub behind. Had a good look and feel. Possibly some built-up grime/rust I missed before. Scrubbed/lightly scraped that off and refitted.

It was getting late, only the new Contitech belt to go on.

Fingers crossed.