Whine or trumpet sound or whale sound and MOT

Ed3 · 18th July 2022, 21:19

On late CDTi - as revs increase there is a loud whine, or trumpet like or whale sound, where the first issue is if this sound is an air leak (possibly between air filter and turbo) - could that affect emissions to fail a looming MOT? I have mainly owned petrol cars previously.

Before the heat wave and after doing my repairs (for the o/s front coil spring, driveshaft and low pressure return power steering pipe with o/s front wing off) on my test drive I heard a faint whine sound when changing down into 3rd. It has now increased and is as many mention in past threads that the sound appears (rear of o/s engine bay) after increasing the revs from tick over.

I wonder if it is likely to be the pipe between the air filter and turbo?

Does not sound like a belt, but I could be wrong.

I have not refilled the air con in 4/5 years and air con was a bit empty when I bought it. But it sounds like an air leak.

I replaced the flex part of the low pressure return power steering pipe into the steering rack and wonder if I dislodged something pushing and pulling on pipes to get the new straight flexible section replacement pipe to fit without rubbing, where the original is shaped with curves to get around obstructions and other pipes.

There is no whine when coasting in neutral or prolonged dipping of the clutch and even at 70 mph on the motorway when dipping the clutch or coasting in neutral for a moment this Rover 75 is amazingly quiet - as in WOW. Just what we want from a 75. So thanks to xsport and others who gave help during the driveshaft etc repairs.

The sound is loud enough to give a headache on a long trip and so getting the radio to work and turn it up (as people do for the whale sound) isn't a solution

I have not yet had a chance to get someone to work the throttle pedal while I use a stethoscope. But will as soon as I can.

Arctic · 18th July 2022, 22:19

Check you fan is working, also that the condenser is in good condition, and maybe get the A/C checked out and filled if both fan and condenser is ok, sound you are most likely hearing is the whooping sound when one or all of the above are not right.

Enhanced by google search is your friend on here

Mike Noc · 19th July 2022, 08:01

Sounds like an air leak after the turbocharger. The inlet manifolds have been known to split at the seams, although it is rare, so take the acoustic engine cover off and get someone to rev the engine while you examine it. Failing that probably a split hose somewhere on the boosted air side.

Ed3 · 21st July 2022, 11:21

Just did a first short trip since my starting this thread. On start up there is no sound at all even when I blip the throttle. The sound increases as the car warms up. There is an inline thermostat installed and the car hits running temperature quickly and the sound is noticeable in a 30 mph built up area. (It was much more noisy at motorway speed which is what I use the car for) It seems that will be an air leak? I am waiting to get someone willing to work the throttle while I listen under the bonnet. I can easily see the pipe from the air filter to turbo. But not yet found the pipe from turbo out and onwards.

Will I be OK to book an MOT and sort the noise after the MOT?

Mike Noc · 21st July 2022, 13:18

The diesel MOT emission test is a visible smoke test. Luckily the engine won't be under any load during the test, so, although an air leak after the MAF can cause smoke due to overfueling you should be OK on a light throttle as there should still be plenty of excess air available.

A bottle of injector cleaner and driving it like you stole it before the test has worked for me come MOT time, and my injectors have now covered over 427k miles.

Ed3 · 21st July 2022, 23:19

Found this about using smoke to find an air intake leak
https://www.youtube.com/watch?v=u-6V...26RepairCentre
But I don't know which is more difficult, - finding an air intake leak. Or finding an expensive elusive smoke machine.

Is it relevant that the pipe before the MAF is sweating greasy stuff to a fairly unpleasant level, too dirty to touch the outside of the pipe and far more than 4/5 years ago when I bought the car?

Arctic · 22nd July 2022, 08:48

Quote:

Originally Posted by Ed3

Found this about using smoke to find an air intake leak
https://www.youtube.com/watch?v=u-6V...26RepairCentre
But I don't know which is more difficult, - finding an air intake leak. Or finding an expensive elusive smoke machine.

Quote:

Is it relevant that the pipe before the MAF is sweating greasy stuff to a fairly unpleasant level, too dirty to touch the outside of the pipe and far more than 4/5 years ago when I bought the car?

Hi Ed.
Are you referring to the intercooler hose? if so as it swollen and is it greasy, you are not getting any smoke if you give it some welly? can you take a photo of pipe that is sweating as you say.

Ed3 · 22nd July 2022, 13:29

I have taken the MAF and EGR off and cleaned and it seems the hoses from the intercooler to the EGR are in very good condition. It was just the hoses had attracted dirt on the outside (and inside).

The EGR and MAF are clean examples. Obviously both needed a little clean.

The car history is on the production line March 2005 CDTi with one previous owner who used it as a work horse for just over a decade and my guess is he put a new MAF, EGR and pipes a year or so before I bought it.

The usual air intake sludge was mostly soft. The inlet manifold seems due for taking off to clean which I can try after the MOT next week.

The small vacuum pipe on the EGR is worn into at least a near hole from bending to press against the sharp edge of the inlet manifold. I put tape for now but will need to look at that.

I will need to get back to tracing the air intake leak near the air filter/turbo. .

Ed3 · 6th August 2022, 19:14

Could the whine be the CDTi fuel filter?

The update is the whine sound is not there on start up from when the car is not used, but gets quite loud after about 8 miles when taking foot off the accelerator.

Not had someone with me so they can rev when I am under the bonnet but it may be that the sound is more to the rear/mid passenger side of the engine bay.

Then I realised the main thing I touched in the engine bay on the passenger side was while doing various major o/s strut & driveshaft repairs, - I changed the fuel filter.

From a Google search there are forums in the USA where owners of 4x4 pickups can sometimes get a whine from the fuel filter if the O ring or another does not do it's job correctly.

Other forums mention that if a fuel pump is strained that can cause noise

I have done a quick check on the fuel filter. It is screwed into it's housing tightly. But the fuel filter clamp will not tighten enough to hold the fuel filter and the very bottom of the fuel filter is resting and possibly bouncing on the various pipes that are below. I am not sure if that direct contact of the bottom of the fuel filter resting on big pipes (not sure if a big coolant pipe) can be a problem after 8 miles.

Mike Noc · 7th August 2022, 06:18

If you can't clamp the filter tightly then are you sure you have the correct filter?

To see if it is the cause of the noise put a bit of cardboard down the side so you can lift and clamp the filter and go for a drive.

18th July 2022, 21:19	#1
Ed3 Loves to post Rover 75 CDTi saloon Join Date: Nov 2017 Location: UK Posts: 306 Thanks: 88 Thanked 29 Times in 26 Posts	Whine or trumpet sound or whale sound and MOT On late CDTi - as revs increase there is a loud whine, or trumpet like or whale sound, where the first issue is if this sound is an air leak (possibly between air filter and turbo) - could that affect emissions to fail a looming MOT? I have mainly owned petrol cars previously. Before the heat wave and after doing my repairs (for the o/s front coil spring, driveshaft and low pressure return power steering pipe with o/s front wing off) on my test drive I heard a faint whine sound when changing down into 3rd. It has now increased and is as many mention in past threads that the sound appears (rear of o/s engine bay) after increasing the revs from tick over. I wonder if it is likely to be the pipe between the air filter and turbo? Does not sound like a belt, but I could be wrong. I have not refilled the air con in 4/5 years and air con was a bit empty when I bought it. But it sounds like an air leak. I replaced the flex part of the low pressure return power steering pipe into the steering rack and wonder if I dislodged something pushing and pulling on pipes to get the new straight flexible section replacement pipe to fit without rubbing, where the original is shaped with curves to get around obstructions and other pipes. There is no whine when coasting in neutral or prolonged dipping of the clutch and even at 70 mph on the motorway when dipping the clutch or coasting in neutral for a moment this Rover 75 is amazingly quiet - as in WOW. Just what we want from a 75. So thanks to xsport and others who gave help during the driveshaft etc repairs. The sound is loud enough to give a headache on a long trip and so getting the radio to work and turn it up (as people do for the whale sound) isn't a solution I have not yet had a chance to get someone to work the throttle pedal while I use a stethoscope. But will as soon as I can. Last edited by Ed3; 18th July 2022 at 21:21..

18th July 2022, 22:19	#2
Arctic Give to Learn Freelander 2 Join Date: Aug 2010 Location: West Midlands Posts: 18,713 Thanks: 1,155 Thanked 6,407 Times in 3,874 Posts	Check you fan is working, also that the condenser is in good condition, and maybe get the A/C checked out and filled if both fan and condenser is ok, sound you are most likely hearing is the whooping sound when one or all of the above are not right. Enhanced by google search is your friend on here __________________ Arctic Givology Learn to Give Everything is Achievable ad altiora tendo. Check out our Nano meet dates http://www.midlandsnanomeets.co.uk/ http://www.the75andztclub.co.uk/index.php?thepage=howto " You do the work , we supply the expertise "

21st July 2022, 23:19	#6
Ed3 Loves to post Rover 75 CDTi saloon Join Date: Nov 2017 Location: UK Posts: 306 Thanks: 88 Thanked 29 Times in 26 Posts	Found this about using smoke to find an air intake leak https://www.youtube.com/watch?v=u-6V...26RepairCentre But I don't know which is more difficult, - finding an air intake leak. Or finding an expensive elusive smoke machine. Is it relevant that the pipe before the MAF is sweating greasy stuff to a fairly unpleasant level, too dirty to touch the outside of the pipe and far more than 4/5 years ago when I bought the car? Last edited by Ed3; 22nd July 2022 at 06:15..

19th July 2022, 08:01	#3
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,548 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Sounds like an air leak after the turbocharger. The inlet manifolds have been known to split at the seams, although it is rare, so take the acoustic engine cover off and get someone to rev the engine while you examine it. Failing that probably a split hose somewhere on the boosted air side.

21st July 2022, 11:21	#4
Ed3 Loves to post Rover 75 CDTi saloon Join Date: Nov 2017 Location: UK Posts: 306 Thanks: 88 Thanked 29 Times in 26 Posts	Just did a first short trip since my starting this thread. On start up there is no sound at all even when I blip the throttle. The sound increases as the car warms up. There is an inline thermostat installed and the car hits running temperature quickly and the sound is noticeable in a 30 mph built up area. (It was much more noisy at motorway speed which is what I use the car for) It seems that will be an air leak? I am waiting to get someone willing to work the throttle while I listen under the bonnet. I can easily see the pipe from the air filter to turbo. But not yet found the pipe from turbo out and onwards. Will I be OK to book an MOT and sort the noise after the MOT?

21st July 2022, 13:18	#5
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,548 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	The diesel MOT emission test is a visible smoke test. Luckily the engine won't be under any load during the test, so, although an air leak after the MAF can cause smoke due to overfueling you should be OK on a light throttle as there should still be plenty of excess air available. A bottle of injector cleaner and driving it like you stole it before the test has worked for me come MOT time, and my injectors have now covered over 427k miles.

22nd July 2022, 13:29	#8
Ed3 Loves to post Rover 75 CDTi saloon Join Date: Nov 2017 Location: UK Posts: 306 Thanks: 88 Thanked 29 Times in 26 Posts	I have taken the MAF and EGR off and cleaned and it seems the hoses from the intercooler to the EGR are in very good condition. It was just the hoses had attracted dirt on the outside (and inside). The EGR and MAF are clean examples. Obviously both needed a little clean. The car history is on the production line March 2005 CDTi with one previous owner who used it as a work horse for just over a decade and my guess is he put a new MAF, EGR and pipes a year or so before I bought it. The usual air intake sludge was mostly soft. The inlet manifold seems due for taking off to clean which I can try after the MOT next week. The small vacuum pipe on the EGR is worn into at least a near hole from bending to press against the sharp edge of the inlet manifold. I put tape for now but will need to look at that. I will need to get back to tracing the air intake leak near the air filter/turbo. .

6th August 2022, 19:14	#9
Ed3 Loves to post Rover 75 CDTi saloon Join Date: Nov 2017 Location: UK Posts: 306 Thanks: 88 Thanked 29 Times in 26 Posts	Could the whine be the CDTi fuel filter? The update is the whine sound is not there on start up from when the car is not used, but gets quite loud after about 8 miles when taking foot off the accelerator. Not had someone with me so they can rev when I am under the bonnet but it may be that the sound is more to the rear/mid passenger side of the engine bay. Then I realised the main thing I touched in the engine bay on the passenger side was while doing various major o/s strut & driveshaft repairs, - I changed the fuel filter. From a Google search there are forums in the USA where owners of 4x4 pickups can sometimes get a whine from the fuel filter if the O ring or another does not do it's job correctly. Other forums mention that if a fuel pump is strained that can cause noise I have done a quick check on the fuel filter. It is screwed into it's housing tightly. But the fuel filter clamp will not tighten enough to hold the fuel filter and the very bottom of the fuel filter is resting and possibly bouncing on the various pipes that are below. I am not sure if that direct contact of the bottom of the fuel filter resting on big pipes (not sure if a big coolant pipe) can be a problem after 8 miles.

7th August 2022, 06:18	#10
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,548 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	If you can't clamp the filter tightly then are you sure you have the correct filter? To see if it is the cause of the noise put a bit of cardboard down the side so you can lift and clamp the filter and go for a drive.