M800 - Strange Thuk-Thud noise

rrsteer · 15th June 2009, 21:56

Hi,

Want to seek the forum for help regarding a strange noise that comes from my M800. The car in question is 2 years old. The noise is a thuk - thud noise which I hear when I pull her in first gear. This is especially true, when I decelerate through the engine and pull the running car in first gear. And sometime I can hear the same noise in slow speeds while I pull through a corner in lower gears. Notice - the sound is not heard everytime I do the above routine.

This noise has been there eversince I have got the car. Have taken the car to various authorised service stations and no one has been able to diagnose the fault. Mostly whenever the car is in the service station, the mechanics even fail to replicate the sound

Otherwise, the car is running fine and has clocked around 23K kms and has given no other cause of concern.

Will look out for your responses.

anupmathur · 15th June 2009, 22:09

Is it a mechanical sound or more like exhaust system sound?

Jaggu · 15th June 2009, 22:51

Have your mechs checked the engine/gear box mounts in the car? Exhaust headers if it is touching body in the front?

rrsteer · 16th June 2009, 12:24

Quote:

Originally Posted by anupmathur

Is it a mechanical sound or more like exhaust system sound?

Its a mechanical sound.

I'll get the engine and gear box mounts checked.
Thanks

cnaganathan · 16th June 2009, 14:00

- yes. But check the contents of your boot. Sometimes it is an odd item like a mug or bucket that you keep in the boot or an unsecured Stepney / jack / tools bag that is the cause.

Mr_Bean · 3rd July 2009, 15:39

I am not an expert in this

Could be a lower arm problem, normally it comes with a bush & if it is worn out then you could heard thud thud sound. I had this noise on my car when I used to accelerate & brake hard on an open/bad stretch.

If you hear this while taking turns, then you need to check drive shaft. If you hear the sound when turning right, then the left drive shaft can be weak & vice versa.

aaggoswami · 3rd July 2009, 17:11

If lower arm is the problem then one can have some feel of irregular movement of wheels in the steering. Moreover a bad lower arm can ruin the tyres within very short time. But this is the problem ever since the car was bought. I think it might be related with suspenision if engine mounts are good.
I feel its suspension, may be the front. Apron might not be in perfect shape, but this is a long shot. If mounts are good, then suspension needs to be checked.

Psycho · 3rd July 2009, 18:41

Can you also ask your mechanic to check for a diff fault or low oil level in the gearbox.

15th June 2009, 21:56	#1
rrsteer Senior - BHPian Join Date: Dec 2008 Location: 144022 Posts: 1,234 Thanked: 3,119 Times	M800 - Strange Thuk-Thud noise Hi, Want to seek the forum for help regarding a strange noise that comes from my M800. The car in question is 2 years old. The noise is a thuk - thud noise which I hear when I pull her in first gear. This is especially true, when I decelerate through the engine and pull the running car in first gear. And sometime I can hear the same noise in slow speeds while I pull through a corner in lower gears. Notice - the sound is not heard everytime I do the above routine. This noise has been there eversince I have got the car. Have taken the car to various authorised service stations and no one has been able to diagnose the fault. Mostly whenever the car is in the service station, the mechanics even fail to replicate the sound Otherwise, the car is running fine and has clocked around 23K kms and has given no other cause of concern. Will look out for your responses.
	() Thanks

15th June 2009, 22:09	#2
anupmathur Senior - BHPian Join Date: Sep 2007 Location: New Delhi Posts: 3,095 Thanked: 306 Times	Is it a mechanical sound or more like exhaust system sound?
	() Thanks

15th June 2009, 22:51	#3
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,212 Thanked: 15,892 Times	Have your mechs checked the engine/gear box mounts in the car? Exhaust headers if it is touching body in the front?
	() Thanks

16th June 2009, 14:00	#5
cnaganathan BHPian Join Date: Jul 2008 Location: Chennai Posts: 281 Thanked: 48 Times View My Garage	- yes. But check the contents of your boot. Sometimes it is an odd item like a mug or bucket that you keep in the boot or an unsecured Stepney / jack / tools bag that is the cause.
	() Thanks

3rd July 2009, 15:39	#6
Mr_Bean BHPian Join Date: Nov 2008 Location: Bangalore Posts: 891 Thanked: 241 Times View My Garage	I am not an expert in this Could be a lower arm problem, normally it comes with a bush & if it is worn out then you could heard thud thud sound. I had this noise on my car when I used to accelerate & brake hard on an open/bad stretch. If you hear this while taking turns, then you need to check drive shaft. If you hear the sound when turning right, then the left drive shaft can be weak & vice versa.
	() Thanks

3rd July 2009, 17:11	#7
aaggoswami Senior - BHPian Join Date: May 2007 Location: Vadodara Posts: 4,982 Thanked: 2,930 Times	If lower arm is the problem then one can have some feel of irregular movement of wheels in the steering. Moreover a bad lower arm can ruin the tyres within very short time. But this is the problem ever since the car was bought. I think it might be related with suspenision if engine mounts are good. I feel its suspension, may be the front. Apron might not be in perfect shape, but this is a long shot. If mounts are good, then suspension needs to be checked.
	() Thanks

3rd July 2009, 18:41	#8
Psycho Senior - BHPian Join Date: Jul 2004 Location: Bangalore Posts: 1,043 Thanked: 110 Times View My Garage	Can you also ask your mechanic to check for a diff fault or low oil level in the gearbox.
	() Thanks