sqeeling noise from engine bay under load

[Mart]

I have a high-pitched squealing noise coming from the engine under load and at very hi revs offload. It seems to be completely throttle-position related and load related as I can get the noise in any gear, at any revs at any speed. I can even get the throttle set just right and make the noise come and go with the slightest movement of the pedal.



It’s not a fan belt noise and is constant with the throttle set pass a certain point. Don't think it’s the turbo as it’s only under load and not when free revving.



Just had the engine rebuilt after new head and 2 cylinders relined. Everything else sounds ok. Wife also says it used to do it before the rebuild but very intermittent - air con?



I think it could be:



1) Vacuum related split pipe etc?

2) EGR valve as I disabled it before the rebuild - poss. knackered EGR?

3) Air Con unit squealing - haven't had it re-gased yet so can't run the compressor.

4) Don't know?



Help please its driving me mad and I'm kind of worried that its something expensive and we go away with the caravan (1600kg) end of May.



Cheers

[dirtydog]

Just a thought but under no load the Turbo isnt doing anything untill around 4000rpm so it could well be turbo related. Saying its pedal related make me think this too as pedal position accounts for almost the entire turbo pressure reading.

Anyone else?

[Uplander]

Hi,
Could it be water pump noise (screech). Almost impossible to say from a distance but if your a dab hand with a low tech diagnostic tool ie using a wooden handled large screwdriver as a stethoscope ( it works - yup) and carefully placing the business end on various parts of the engine and your lug (ear) on the handle ,you can pinpoint where the noise is emanating from - and if your a novice - also frighten yourself half to death ! This does sound like a pump or a pulley to me !

Uplander (hope it's an easy fix)

[Mart]

Hi,
Could it be water pump noise (screech). Almost impossible to say from a distance but if your a dab hand with a low tech diagnostic tool ie using a wooden handled large screwdriver as a stethoscope ( it works - yup) and carefully placing the business end on various parts of the engine and your lug (ear) on the handle ,you can pinpoint where the noise is emanating from - and if your a novice - also frighten yourself half to death ! This does sound like a pump or a pulley to me !

Uplander (hope it's an easy fix)

I'm thinking its the turbo now and want to try removing the rubber section between the turbo and air inlet to engine and see if the noise stops i.e. no back-pressure on the turbo therefore no load therefore no squeal?



Worried that this loss of backpressure may make the turbo bearing go due to uneven loading etc?



Any thoughts?



Cheers

[laser_jock@work]

I'd start looking for a worn pulley - most probably the tensioner. Grab it- and see if theres any wobble.

Nevillef

[Tallyman]

Are you sure you haven't got the aircon on? Mine was making similar noises when I used the aircon. It was the belt screaming as the aircon compressor locked up because of a knackered pressure release valve in the passenger footwell not allowing the gas to circulate.

[Mart]

have any update....

The squeal only happens when the thermostat is open. When you drive from cold there is no prob at all at any revs or throttle position. Once the engine is up to temp still no squeal. Its only when the thermostat opens (I am assuming this by the heater temp changes at that moment) that the squeal starts and within a few seconds is back to normal squealing.



Answers on a postcard please?



Possibilities:



1) Water pump - but why no squeal when free revving and why throttle position related?

2) Turbo - but that would squeal all the time inc free revving as pressures/loads on it are the same?

3) Belt tensioner - could be but why not when free revving

4) Aircon - no gas in it as the mo so can't switch it on but do remember before that the thing used to squeal when you accelerated?



Answers on a postcard please?.... cause I'm stuck.



Cheers

[TonyN]

Has anyone mentioned the crank pulley yet? its the harmonic balencer, the hub and pulley part are glued together via a rubber ring, if the glue comes apart, the pulley part spins on the hub, and makes a noise like loose belts.

[TonyN]

4) Aircon - no gas in it as the mo so can't switch it on but do remember before that the thing used to squeal when you accelerated?


Cheers

Even when off, the pulley still spins, if the clutch is dragging it'll make a noise, also check the tensioner pulley bearing. Better just to remove the belt completely, then you can rule it out.

[Mart]

I think I’ve found the prob. I was having look around to find the squeal and notice if you rev the engine hard a small puff of smoke comes up from the inlet manifold and the squeal comes at exactly the same time. On closer inspection its seems injector number 3 (counting 1 from the front of the car) is leaking.



My guess is as the pressure builds in the manifold from the turbo it eventually forces its way out through the injector. Which is why its throttle position related.



OR



The fuel pump allows a greater pressure to the injector, which then forces out through a crack etc



Either way its directly related to the throttle position and once the engine is hot.

judging by amount of fuel in and around the injector it would seem that the noise comes from high pressure leaking. Probably cracked when the new head was done ?

Any thoughts on whether this is tuff luck or if the mechanic should sort it for free and parts?

Cheers

[Mart]

update on the squeeling.........

had the injector repalced and the noise is still there. my mechanic took it to a turbo specialist and they say its turbo noise definatley or waste gate. My prob is that I've spent all my cash on the new head and rebore etc and now looking at a turbo rebuild.

What are my options and costs:
1) new turbo £ ?
2) rebuild £ ?
3) leave the npoise till it breaks £ ?

I'm going down to the new forest end of the month with a 1600kg caravan in tow so I need to know whether to replace, repair or leave it and wait till the noise gets unbarable. What I don't want is a broken turbo that cost me £1000+ to fix.

Help please!

[Mart]

update on the squealing.........


had the injector replaced and the noise is still there. my mechanic took it to a turbo specialist and they say its turbo noise definitely or waste gate. My prob is that I've spent all my cash on the new head and rebore etc and now looking at a turbo rebuild.



What are my options and costs:

1) New turbo £ ?

2) Rebuild £ ?

3) leave the noise till it breaks £ ?



I'm going down to the new forest end of the month with a 1600kg caravan in tow so I need to know whether to replace, repair or leave it and wait till the noise gets unbearable. What I don't want is a broken turbo that cost me £1000+ to fix.



Help please!

well it’s going off to a turbo specialist Monday £150-650 depending on whether its a baring fault or needs a full exchange replacement plus my mechanics cost!! Why oh why did I buy a surf?! Cause there great to drive and look cool..... unfortunately they cost an arm and a leg to keep on the sodin' road! Losing my patience with this car, but I'm so far in £3200 already plus turbo so lets say £4k..... its only worth £5k at best!!! And to top it all I think the tyres need replacing!!!



Anyway rant over....I'll post the outcome soon and costs, phone numbers and quality of service.



Cheers

[Lomcevac]

Let us know what happened Mart as I have exactly the same problem.

[Mart]

Let us know what happened Mart as I have exactly the same problem.

Update......

had the replacement turbo fitted and squeal still there! New turbo sounds good though and mech says the old one did have some play in the bearings.



Mech will have the surf back in and investigate / repair the squeal further. I suspect EGR valve or leaking seal.



What does your noise sound like? Start? Etc



Keep you updated



Mart

[Guest]

I think I’ve found the prob. I was having look around to find the squeal and notice if you rev the engine hard a small puff of smoke comes up from the inlet manifold and the squeal comes at exactly the same time. On closer inspection its seems injector number 3 (counting 1 from the front of the car) is leaking.



My guess is as the pressure builds in the manifold from the turbo it eventually forces its way out through the injector. Which is why its throttle position related.



OR



The fuel pump allows a greater pressure to the injector, which then forces out through a crack etc



Either way its directly related to the throttle position and once the engine is hot.

judging by amount of fuel in and around the injector it would seem that the noise comes from high pressure leaking. Probably cracked when the new head was done ?

Any thoughts on whether this is tuff luck or if the mechanic should sort it for free and parts?

Cheers

Mart.

I would say that the only way this should happen is one of two things.

1. The monkey tightened the injector too much and damaged the thread or worse still cracked the head around the thread (pretty unlikely as the head is pretty strong around there).

2. More likely, he fitted the injector either with the copper sealing washer in the wrong place, missed it completely or didn't fit a new one if the old one was badly compressed.

I would say it's down to him to fix.

Cheers