Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
Strange bottom engine noise
Hello everyone. I have this strange noise in the bottom part of the engine in my recently purchased D4. It is a TDV6 3.0 245cv without DPF. July 2010. 140.000kms on the clock. It only happens in idle, with the engine hot. Not on cold, not on acceleration, not even with a slight pedal in neutral. Only in idle. If I stop the engine for about 20 minutes, when I start again the engine, it does not make the sound. It starts making it again very subtle when about 45 second passes.
I cannot link it with anything and it does not seems related with crank or timing issues, due to the strange interval and “frequency” when it sounds. Timing belt is done. Aux belt and tensioner done. Gearbox maintenance done 3 years ago. No strange ticking on startup even when cold. I’ve been searching through YouTube videos and posts here and in other forums but I’m not able to find any similar noise.
Oil is just changed. Ravenol FDS 5w30.
I have just recorded a video.
Any help is appreciated. I’m quite worried about if the engine is going to self destruct.
Thanks everyone.
[url] ?si=8gKfnGVv6jA-TA8C[/url]
20th Sep 2024 1:25 pm
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6406
sound like main aux belt pulley
had two pulleys fail on the way to UK last year sounded much more "interesting" epecially for occupants of other vehicles lol
20th Sep 2024 2:05 pm
AlbertoMarin00
Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
Changed two days ago, genuine one..
20th Sep 2024 2:12 pm
AlbertoMarin00
Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
grzesiul wrote:
sound like main aux belt pulley
had two pulleys fail on the way to UK last year sounded much more "interesting" epecially for occupants of other vehicles lol
Changed two days ago, genuine one..
20th Sep 2024 2:13 pm
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6406
checked other pulleys while at it?
20th Sep 2024 2:27 pm
AlbertoMarin00
Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
Nope, Im going to remove the aux belt and check. I have been talking with an expert in this engines here and he goes for crankshaft bearings... only sounds when hot and idle due to reduced oil pressure.
20th Sep 2024 2:29 pm
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6406
i guess it gets quieter with RPMs? if so got to be a pulley
might be also some other bearing on alternator, water pump steering pump I do not believe it is more dramatic problem with the motor
20th Sep 2024 2:39 pm
rrhool
Member Since: 28 Aug 2014
Location: Norfolk
Posts: 4525
Aux belt tensioner, or alternator one way clutch ?Richard
D3 SE 2007. Triumph 2.5Pi 1973. Ferguson TEA20 1948.
Discovery 2 4.0 ES 2001- Gone
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20th Sep 2024 3:14 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5052
AlbertoMarin00 wrote:
Nope, Im going to remove the aux belt and check. I have been talking with an expert in this engines here and he goes for crankshaft bearings... only sounds when hot and idle due to reduced oil pressure.
That's not the sound of worn main or big end bearing, I'd be in agreement with grzesiul for aux belt tensioner or worn a pulley bearing.
If you remove the aux belt and run the engine it should eliminate the engine. If the noise is still there check the timing belt tensioner and idlers. Be prepared for a raft of fault codes if the engine is run without the aux belt, but you can just clear them afterwards.yµ (idµ - eAµ) ψ=mψ
20th Sep 2024 3:17 pm
AlbertoMarin00
Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
After a whole afternoon wiggling with the aux belt, I do not have any conclusion. When I removed the aux belt, the sound was not there, but the engine had cooled down, I did not want to run it for long without the aux belt.. five minutes later the sound did not appear. After that, I reinstalled the belt, and about 15 minutes of idling later, the sound reappeared. I am going to bring it to the dealer and see if they can see something.
Thanks everyone
20th Sep 2024 5:34 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5052
Bearing/pulley or tensioner on the aux belt failing, shouldn't be any trouble for your mechanic to locate. yµ (idµ - eAµ) ψ=mψ
20th Sep 2024 5:44 pm
AlbertoMarin00
Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
Yup, I guess. I’m still worried because it sounds more like “engine” than auxiliar components. I never heard an aux pulley/pump/alternator etc sounding like that. But I also think that, if it was a thing of crankshaft bearing or something like that, the sound would be constant, and not kind of “sound, fade out… sound, fade out…”
20th Sep 2024 7:11 pm
AlbertoMarin00
Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
Also, I have another question.. the water pump in this engine is moved with the aux belt? I’m thinking of removing again the belt and let the car sit for 20 minutes idling until I see if the sound comes back or not. If the water pump does not depend on the aux belt,I can connect a battery charger and let it idling. I think that this engine running on idle without viscous fan is not going to overheat in that time..
Thanks everyone.
20th Sep 2024 7:15 pm
AlbertoMarin00
Member Since: 14 Nov 2023
Location: Burgos
Posts: 19
Also another thing I have reminded right now. When running engine with the aux belt installed but without the viscous fan, the part where the viscous screws (water pump?) started making a clicking noise. May this be related?
20th Sep 2024 7:19 pm
DN D3 Decade
Member Since: 23 Jun 2006
Location: W.London.
Posts: 2345
Yes the water pump is driven by the aux belt. Maybe the water pump or it’s bearing is on the way out. If you take the aux belt off to see if it quietens, don’t run it for very long like that. Certainly NOT 20 mins D3 owned from new, P017 brake recall, BAS FBHIC, new FBH, LR013487 oil pump, new water pump. RRS front lower suspension arms. New suspension compressor/ relay. New Denso alternator. CuNifer rear brake pipes. New GKN rear propshaft. New HPFP belt & tensioner. New A/C Condenser.NO WARRANTY for many many years.
Last edited by DN on 20th Sep 2024 8:31 pm. Edited 1 time in total
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