Pulley noise, but where from?

[Kidders]

I'm getting a rattly, squeaky type of noise occur at 4k under load. When the engine is warming up you can hear the noise by gently revving (i.e no load) There is no noise from start up, hot or cold. When hot, you cannot hear the noise until you drive it, its only when warming that it can be heard at a standstill.

So far I have replaced -

Cambelt with tensioner kit, genuine parts
Genuine water pump
Deflection/idler pulley (Gates/INA part, had another new one and swopped but noise remains)
Auxiliary belt tensioner as of tonight.


With the bonnet up it sounds like its coming from the rear of the engine but its really hard to tell as its difficult to replicate unless you drive it.

The only things that haven't been replaced is the alternator and the PAS pump. I've never known a PAS pump to make a intermittent, pulley type noise like a worn bearing.

Any ideas?

 

[evilrob]

By deduction the only spinny things left are the alternator, PAS pump or Aircon pump if you've got one?

Try turning the steering wheel to full lock - that tends to make the PAS pump angry; might produce a similar sound and possibly narrow it down to that?

 

[Kidders]

No added noise when turning the wheel lock to lock. I spun the pump by hand and it seemed fine (belt off) A/C when off freewheels, when switched on and clutch engaged, no difference in noise. I'm looking into the alternator as its the easiest thing on the list to change next! Just strange that it makes the noise bang on 4k in every gear, then tends disappears over that RPM, you can just make out the noise as it hits 6k. Maybe the bearings in the alternator have dried out? The car hasn't had much use the past few years, only clocking up 3k since 2010!

 

[Kidders]

Done some more diagnosis tonight, with the help of an assistant i.e my wife, who also listened for me (4 ears better than 2) and its almost certainly the PAS pump making a squeaking noise from cold, the same noise under load at 4k when hot. So 2nd hand replacement on its way, hopefully that will cure it, bloody annoying!

 

[Kidders]

I've replaced the PAS Pump, no change. I'm almost certain the noise is coming from the middle of the engine, i.e the cam pulleys.

I had the cambelt replaced a couple of weeks ago, had a quick look behind the cover, belt doesnt seem very central on the cams?

Is it possible to over or under tension the cambelt? Not having done the job myself I cant answer that one.

All I can say, is that the noise seems to be getting worse under load, its like a squeaking, dry bearing noise that co-incides with the point the cam timing advances just before 4k and towards 6k. Can the VCT assembly make any noise if there is a problem?

Appreciate any help or advice please.

 

[quest63]

The cambelt position looks ok to me. Theres a process for setting up the tensioner properly was it followed correctly?

If your not sure get it done again

 

[Kidders]

The cambelt position looks ok to me. Theres a process for setting up the tensioner properly was it followed correctly?

If your not sure get it done again

Bloody hope so! The aux belt is coming off tomorrow and then a cold start, which is when it made the most noise.

Reading up it seems the belt position is normal.

 

[Kidders]

Ok I've fixed it. Removed the aux belt, no noise apart from the usual cambelty noise you would expect.

Spun the alternator and apart from a slight rumble, nothing untowards to make me believe it was at fault

So I bought a replacement auxbelt from ECP, a continental contitech, visually big difference,the plain side has a grippy surface in comparison to the Motorcraft one, the ribs themselves looked more fibrous too. Boring belt tech there.

Anyway, after a struggle to fit the thing I soon found out the reason for the noise, it appears the old belt had stretched but condition wise it looked fine with no cracking or deterioration, there is a record of it being changed in receipts I have, changed at 50 k now on 73k, but done in 2005! So age has killed it.

In fact the new belt is so tight that it will be difficult to slacken off the tensioner to remove it in the future, there is no play at all! Result.

Quick start up, silent, drive down the road and its superb, just pure engine noise now. Can't believe it was that simple!