Hi guys,

I'm getting a hissing sound under acceleration noticeable from 2000 rpm.  I've checked the turbo outlet hose down to the intercooler & back to the inlet manifold and cannot see any obvious signs of cracking.  

What else could be causing this?

Thanks in advance.  Car is 2008 mk 2.5 focus 1.6tdci.

Have you checked underside?
Splits can be very small and hard to see until pressure builds up in the system.

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7 minutes ago, Stoney871 said:

Have you checked underside?
Splits can be very small and hard to see until pressure builds up in the system.

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Hi Clive,

Yes i have as much as i could see.  Some of the pipes had quite a lot of gunk on them so wiped clean and looked as much as i could underneath with the car on ramps.  Is this the most likely cause?  If so maybe I'll have to remove them and inspect?  Or possibly wait until the noise becomes more obvious with the bonnet up and be able to narrow it down better.  You can hear it more in the car than with the hood up!

5 hours ago, Albert27 said:

Or possibly wait until the noise becomes more obvious with the bonnet up and be able to narrow it down better.  You can hear it more in the car than with the hood up!

Turbo pressure is related to power, not to rpm. So it can be very difficult to test with the car in the driveway.

I have a pressure display in my car, and I can see it going well up the scale at about 1800rpm in 5th gear if I open the throttle a bit.

But at low throttle openings and well over 2000rpm, there is hardly any boost pressure.

Sometimes you have to remove the hoses to find small splits. There is up to 20psi inside at full boost, and splits that are invisible  when un-pressurised will open up a bit at that pressure. Do not forget the rigid pipes and fittings. Quite a lot are plastic on the 1.6, and have been known to crack or get holes.

I can not think of another likely cause of a hiss only under acceleration. I assume it also happens when climbing a hill in a highish gear, so the engine is made to work. And stops whenever the throttle is released.

Exhaust system leak, allowing turbo noise to be heard in the car? A bit unlikely, but quite easy to check.

7 hours ago, Tdci-Peter said:

Turbo pressure is related to power, not to rpm. So it can be very difficult to test with the car in the driveway.

I have a pressure display in my car, and I can see it going well up the scale at about 1800rpm in 5th gear if I open the throttle a bit.

But at low throttle openings and well over 2000rpm, there is hardly any boost pressure.

Sometimes you have to remove the hoses to find small splits. There is up to 20psi inside at full boost, and splits that are invisible  when un-pressurised will open up a bit at that pressure. Do not forget the rigid pipes and fittings. Quite a lot are plastic on the 1.6, and have been known to crack or get holes.

I can not think of another likely cause of a hiss only under acceleration. I assume it also happens when climbing a hill in a highish gear, so the engine is made to work. And stops whenever the throttle is released.

Exhaust system leak, allowing turbo noise to be heard in the car? A bit unlikely, but quite easy to check.

Thanks Peter.

When driving the car it's noticeable on the flat too but only under acceleration and in 2nd gear and above (can't honestly say i've noticed it in first gear.  As soon as i take foot off throttle it's gone.  Taking the pipes off is just jubilee clips right?  Fairly straightforward?  I will wait until I have a day off then remove, clean and inspect.

3 hours ago, Albert27 said:

Taking the pipes off is just jubilee clips right?  Fairly straightforward?

Should be. Sometimes spring clips needing pliers, or latches that open using a screwdriver are used.

The U shaped plastic pipe around the Turbo has been known to fail. Have a look through:

 

9 hours ago, Tdci-Peter said:

Should be. Sometimes spring clips needing pliers, or latches that open using a screwdriver are used.

The U shaped plastic pipe around the Turbo has been known to fail. Have a look through:

 

Thanks for that link.  I've just read through it. Forgive a simpletons question... but when he says the bolt holes have snapped, what does he mean?

Ignore last, I've just figured out form the picture!  Why would that cause the hissing sound though?  Would the pipe be moving away under pressure and thus creating the noise?

1 hour ago, Albert27 said:

Why would that cause the hissing sound though?  Would the pipe be moving away under pressure and thus creating the noise?

TBH, I am not sure if the failed bolt hole in that thread did make the noise. There was also the split in the inner lining of one tube, and what looks like a little hole in the pipe with the metal ring round it. I had to augment the image a bit to see it, under the ring, and below where it says 05 on the tube. And then there was the intercooler return pipe with " a big hole on the underside". I get the impression it was that last one in Liam's case.

But it does show that these holes can be a bit hard to find.

On 02/10/2017 at 10:12 PM, Tdci-Peter said:

TBH, I am not sure if the failed bolt hole in that thread did make the noise. There was also the split in the inner lining of one tube, and what looks like a little hole in the pipe with the metal ring round it. I had to augment the image a bit to see it, under the ring, and below where it says 05 on the tube. And then there was the intercooler return pipe with " a big hole on the underside". I get the impression it was that last one in Liam's case.

But it does show that these holes can be a bit hard to find.

I've found the crack in a crinkled short pipe that runs into the inlet manifold or is the inlet manifold itself(forgive my basic description!).  I'll post some picture shortly below.  I just need some guidance now on:

 

What part is it and is it an easy enough DIY replacement?

Do I need OEM?

Or is there a patch i could put over it and save any expense?

 

6 hours ago, Albert27 said:

What part is it and is it an easy enough DIY replacement?

Do I need OEM?

Or is there a patch i could put over it and save any expense?

Good news you have found a hole! Hopefully it will not be like Liam's car, and have several!

If it is on the concertina part, then I doubt any patch or repair is practical.

But if this is something like the right part:

http://www.ebay.co.uk/itm/FORD-AIR-INLET-MANIFOLD-TURBO-HOSE-PIPE-FOR-FOCUS-MK2-FOCUS-C-MAX-1-6-TDCi-/282185362300?hash=item41b38eeb7c:g:ERQAAOSw4shX4VvL

Then it looks quite easy to replace, though looks can be deceptive. Hopefully it will not need removal of the whole manifold, which means disconnecting the injectors.

For something external, and not to hard to get at, I would use an Ebay pattern part, not OEM. If there is high labour cost or effort, like front wheel bearings or clutch, then quality would be more critical.

 

 

7 hours ago, Tdci-Peter said:

Good news you have found a hole! Hopefully it will not be like Liam's car, and have several!

If it is on the concertina part, then I doubt any patch or repair is practical.

But if this is something like the right part:

http://www.ebay.co.uk/itm/FORD-AIR-INLET-MANIFOLD-TURBO-HOSE-PIPE-FOR-FOCUS-MK2-FOCUS-C-MAX-1-6-TDCi-/282185362300?hash=item41b38eeb7c:g:ERQAAOSw4shX4VvL

Then it looks quite easy to replace, though looks can be deceptive. Hopefully it will not need removal of the whole manifold, which means disconnecting the injectors.

For something external, and not to hard to get at, I would use an Ebay pattern part, not OEM. If there is high labour cost or effort, like front wheel bearings or clutch, then quality would be more critical.

 

 

Thanks Peter!

Ordered the part.  Hopefully it's just a case those bolts will come out and it's a straight forward replacement.  Will update the thread when done.......

Just on a side note.  When I was removing the first bit of pipe from the turbo I found a small amount of oil where it seals with the turbo.  Is that normal?

12 minutes ago, Albert27 said:

I found a small amount of oil where it seals with the turbo.  Is that normal?

Some oil always gets in to the air intake system from the crankcase vent system. And it is probably normal for a turbo to lose a tiny bit of oil from its bearings, there has to be running clearance in the bearings, as the shaft runs on a film of oil. I doubt if any oil seal would be 100% effective at the speed they spin at.

I always find a little bit of oil in my system, and the turbo is still working!

11 minutes ago, Tdci-Peter said:

Some oil always gets in to the air intake system from the crankcase vent system. And it is probably normal for a turbo to lose a tiny bit of oil from its bearings, there has to be running clearance in the bearings, as the shaft runs on a film of oil. I doubt if any oil seal would be 100% effective at the speed they spin at.

I always find a little bit of oil in my system, and the turbo is still working!

That's good to know as I'm at 152,000 miles and still on the original turbo which is somewhat of a miracle!  It was only a small amount thankfully.....

42 minutes ago, Albert27 said:

I'm at 152,000 miles and still on the original turbo

Beat you. 163,000 miles. As far as I know, the turbo is original.

@Tdci-Peter Good news is it doesn't need the whole manifold off.  Bad news or snag for me is when undoing 3 screws on the lower section (picture shortly to follow below) one of them i cannot get at due to obstructions.  It's a Torx head and although i have a head to fit it, I have nothing to put the head on that'll fit in the space. What tool does one use in a tight space like this?  I could do with some kind of mini torx ratchet!

 

 

2 hours ago, Albert27 said:

one of them i cannot get at due to obstructions.

That is the bolt between the ant-shudder/throttle valve & the inlet duct, if I read it right.

In the the Haynes book of  facts, half-truths, lies & fables, it suggests the anti-shudder valve can be removed along with the inlet duct (and the cylinder head cover, though that is not relevant here). Then you do not need to undo this screw until the valve is moved high enough to get to it.

Otherwise I would be reduced to trying to grip a Torx hex bit in Mole grip pliers, or in a 1/4" spanner, and turning it that way, before scouring EBay for a better alternative! A 1/4inch drive ratchet might fit.

43 minutes ago, Tdci-Peter said:

That is the bolt between the ant-shudder/throttle valve & the inlet duct, if I read it right.

In the the Haynes book of  facts, half-truths, lies & fables, it suggests the anti-shudder valve can be removed along with the inlet duct (and the cylinder head cover, though that is not relevant here). Then you do not need to undo this screw until the valve is moved high enough to get to it.

Otherwise I would be reduced to trying to grip a Torx hex bit in Mole grip pliers, or in a 1/4" spanner, and turning it that way, before scouring EBay for a better alternative! A 1/4inch drive ratchet might fit.

Cheers Peter.  Never heard of the anti shudder valve so just looked it up and educated myself by reading the faithful haynes ....... and will attempt another go tomorrow.

1 hour ago, Albert27 said:

Never heard of the anti shudder valve

I bet you have never heard of the Ant-Shudder valve, either.

But then neither had I, until I writ it . Two "the"s as well! I did read it, but not too well.

I was in a bit of a hurry, with dinner imminent!

4 minutes ago, Tdci-Peter said:

I bet you have never heard of the Ant-Shudder valve, either.

But then neither had I, until I writ it . Two "the"s as well! I did read it, but not too well.

I was in a bit of a hurry, with dinner imminent!

Do you know, i didn't even notice your grammatical errors!  But dinner is a good excuse! 

21 hours ago, Tdci-Peter said:

I bet you have never heard of the Ant-Shudder valve, either.

But then neither had I, until I writ it . Two "the"s as well! I did read it, but not too well.

I was in a bit of a hurry, with dinner imminent!

Well, I've got myself into a bit of a pickle this afternoon and need some advice.  

When fitting the new part the hole for the sensor was too narrow and i didn't realise in time and have broken the sensor!  I guess that's the risk you take with ebay parts!  So I put the old part back on and refitted the sensor and rather optimistically hoped i hadn't damaged anything.  Car started fine, drive into second gear and accelerate, turbo kicks in sudden pop noise power lost and smoke out the back.  Engine running rough and acceleration now very slow.

So my deduction is the PCM is getting bad information (or none) from the turbo air sensor (as you look at the inlet manifold turbo hose in my first photo above it's the sensor on the right, nearest the oil cap) and is behaving as if the turbo is not working to compensate hence the smoke?  

What should i do now?  If i disconnect the sensor and run without will the engine return to normal?  

Obvs going to need a replacement, is it a straightforward swap and what is the official name for the sensor?

Any help much appreciated!  

How embarrassing - after writing the above I just went out to the car, looked under the bonnet and found the turbo intercooler hose off because i'd forgotten to tighten the jubillee clip!!  Car is now driving normally!  Forgive my idiocy 

I suppose the sensor might be ok?  No warning lights, should i be concerned?