When I accel in gear I can hear a suction sound almost as though it's coming through the window dash vents.the sound isn't there if I rev in neutral it's only there when in gear.ive never noticed it before and although I assume it's the turbo just spooling I'm unsure.

Could it be exhaust blowin from the front connection?no loss Of power from what I can tell.

On a diesel Focus it is almost certainly a split intercooler hose.

It's a very common occurrence.

Wouldn't it make that sound even if it's revved at idle..?

Depends if you're hitting the boost point of the turbo.

Get someone to have a good listen around the engine bay as the car is revved .

I'm revving it to 4k and there's no change in sound.it only happens under hard accell when driving

I'm revving it to 4k and there's no change in sound.it only happens under hard accell when driving

That is because the engine is under load, in neutral, revving when staitionary the engine is not under load

As Stoney has said, its probably a split intercooler hose, the noise is from blowing, not sucking, boost is produced on demand, you may not notice a difference in performance, but the turbo may have to work harder to maintain the boost, turbo may run hotter and thir may be a loss of economy

Noises can be subjective rather than objective, and the sound may always have been their but you never noticed (eg, - i borrowed my dads car and he suddenly "noticed" scratches that were there for years )

Keep a listen for it to see if it gets worse, if it does check the hoses carefully

I'll check em properly tomorrow,I'm sure the hose was replaced a couple of years ago.remember reading it on some service history.and yeah it's better described as a blow,it sounds as though the air cons coming on and then going off as I stop accelerating

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I would say from the way you say it sounds like aircon going on and off that it will be the intercooler hose.

I'd be mightily surprised if it was anything else tbh.

I've had the hose off that's next to the coolant tank and the hose appears fine to me .would it likely be further down the system or is it generally just that part that splits.ive had my head all around the engine and I can't pinpoint it anywhere as I can't decipher the sounds of belts moving etc

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Thinking of putting it down to the exhaust as it's been on its way out for a while but still worked fine.was an mot advisory on its last mot that the front joints were in poor condition. Could it produce the same noise ?

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It would make a nice blowing noise, yes.

I had exactly the same on mine which turned out to be a split in the rubber intercooler pipe. I found it by looking and feeling the pipe as it is likely that there will be a trace of oil where the split is.

I had exactly the same on my Focus 1.8L TDCi, sounded like air conditioning was kicking in when accelerating. Was a tiny split in the intercooler hose - large hose at top left when under bonnet. This is close to rear of dash hence sound travels into air vents. Ford supply replacement hose but this comes as a full assembly with metal section so over £50 ! But a lot cheaper than a turbo which was my first worry.

Already taken it off mate,no split there.

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I couldn't see a split in the hose either - I've just checked the one I took off and no sign of split. I confirmed that there was a split by wrapping the hose in duck tape. When I drove it again all appeared fine until under sharp acceleration when the tape made the noise even worse. If you haven't found your problem yet give it a try.

Occupied with other things on it ATM.when I take the key out and lock it the wipers come in juddering the heated screen comes on and indicators flicker but not to full illumination and the alarm goes off.i unlock the car and it all continues until I flick the key in the ignition,then it stops and I can drive It fine (besides the air sound)

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So after messin around with the battery terminals fuses etc and nothing working,I took the Jeremy clarkson approach and smacked the underside of the glove compartment near the fuse box with my hand and it hasn't happened since lol

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I've had the same problem recently with my 1.8 tdci and i found that the inter cooler hose had a 2 inch split. Its literary a 2 min job to check, its a 90 degree hose top left of the engine bay. Not sure which is best to replace though... Anybody?

Sorry way ahead of myself i didn't read the whole thread. Sorry People.

That is because the engine is under load, in neutral, revving when staitionary the engine is not under load

As Stoney has said, its probably a split intercooler hose, the noise is from blowing, not sucking, boost is produced on demand, you may not notice a difference in performance, but the turbo may have to work harder to maintain the boost, turbo may run hotter and thir may be a loss of economy

Noises can be subjective rather than objective, and the sound may always have been their but you never noticed (eg, - i borrowed my dads car and he suddenly "noticed" scratches that were there for years )

Keep a listen for it to see if it gets worse, if it does check the hoses carefully

Engine fault light comes on intermittent but disappears if I restart engine.i can't really pinpoint where the noise is coming from so my only guess is a leak from this pipe?or is it normal for that to be around there.

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Found the split and sorted it by putting a layer of wax/glue from a proper glue gun,used some super glue to help close it then put another layer of wax glue ontop to seal it,wrapped electrical tape around it then a bit of gaffa.fixed for now.

The split was hidden from view,and because it was right next to the moving belts there was no way of feeling the air escaping either.
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Found the split and sorted it by putting a layer of wax/glue from a proper glue gun,used some super glue to help close it then put another layer of wax glue ontop to seal it,wrapped electrical tape around it then a bit of gaffa.fixed for now.ImageUploadedByFord OC1398096048.574657.jpgImageUploadedByFord OC1398096060.230196.jpg

The split was hidden from view,and because it was right next to the moving belts there was no way of feeling the air escaping either.

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Nice one - glad you got it sorted