Jackie Posted January 2, 2008 Share Posted January 2, 2008 Having just acquired a Renault Scenic 1.9dci I have noticed an audible whistle which goes on for several minutes after the engine has been switched off. This tone is somewhere about 1kHz and I notice the same thing on a our Renault Megane, also 1.9dci, except in that case the tone can only be heard if the radio is switched on LW where the signals are weak. I assume that there is some electronic device running but have no idea what it is, any clues anyone............................John Link to comment Share on other sites More sharing options...
f1steveuk Posted January 2, 2008 Share Posted January 2, 2008 Is it a turbo diesel? Link to comment Share on other sites More sharing options...
Jackie Posted January 2, 2008 Author Share Posted January 2, 2008 No 1.9dci and the tone is constant............J Link to comment Share on other sites More sharing options...
cooperlola Posted January 2, 2008 Share Posted January 2, 2008 A dci is a turbo diesel, Jackie. (diesel compression injection) Link to comment Share on other sites More sharing options...
Bugsy Posted January 2, 2008 Share Posted January 2, 2008 http://www.renaultforums.co.uk/wheels-tyres/17196-whistle-left-car.html Link to comment Share on other sites More sharing options...
f1steveuk Posted January 2, 2008 Share Posted January 2, 2008 Can't see a wheel bearing making a noise AFTER the engine is switched off!!If it is a turbo, it could be one of two things. Turbo's spina HUGE revs, and can spin for 5 minutes after the engine is switched off. You should never, NEVER rev the engine prior to turning off, indeed some people say let the engine idle for two minutes before turning off, this is because once the engine is off, the oil supply to the turbo bearings does not function, yet the turbo is still spinning. The whine could be failing turbo bearings because of this. Having said that, some manufacturers fit a oil resesvoir that once the engine stops, a solenoid releases, and this then pumps oil to the turbo for a while while it spools down.Sadly, my money is on the first of these two suggestions Link to comment Share on other sites More sharing options...
Jackie Posted January 2, 2008 Author Share Posted January 2, 2008 Sorry meant yes both are 1.9dci. Not the cooling fan and the car is stationary with the engine off. This is a single frequency, and constant in pitch, no air noises. A bit like the whine from a static inverter. In the case of the Scenic the whine is acoustic and comes from under the bonnet whereas in the case of the Megane it can only be heard by having the radio on LW and the whine stops a couple of minutes after stopping the engine in both cases. Also I have noticed that on the Megane it starts again if you turn the lights on which suggests to me that it is something electrical but what. Loose laminations in some transformer like component in the case of the Scenic might account for it? If there is a lubricating pump running for some time after stopping the engine maybe that is what it is. There is no change in the frequency at all, it just stops after a few minutes. Although the frequency of the electrical noise in the Megane and the acoustic noise in the Scenic sound to be similar in pitch, the source could, I suppose, could be two different things! .........J Link to comment Share on other sites More sharing options...
cooperlola Posted January 2, 2008 Share Posted January 2, 2008 There is a lubricating pump on my 1.5 dci Renault engine but it just hums for about 20 seconds - I would not describe it as a whistle. Very odd. Link to comment Share on other sites More sharing options...
Pierre ZFP Posted January 3, 2008 Share Posted January 3, 2008 Maybe you should teach it the words........ Link to comment Share on other sites More sharing options...
Jackie Posted January 3, 2008 Author Share Posted January 3, 2008 OK folks well I started up both cars this am and ran the engines for a few minutes. I then switched off and stuck my head under the bonnet. In both cases I could hear a hum/buzz and in the case of the Scenic the higher frequency tone as well. In both cases the cooling fan was visible and not running. The noises continued for a short time and then something went clunk, I assume a relay, and the noises stopped. I think the noises were coming from high up on the bulkhead to the right hand side looking towards the rear though in the case of the Scenic it is difficult to tell it is so cramped in there and I for one would hate to have to work on the innards. The suggestion of some sort of lubricating pump for the turbo seems possible to me but I really know very little about diesels as must be evident. Could it be a fuel pump and if so why would it run on after the engine is switched off? Anyway since both do similar things I guess it must be normal but puzzling just the same...........J Link to comment Share on other sites More sharing options...
Benjamin Posted January 3, 2008 Share Posted January 3, 2008 [quote user="Pierre ZFP"]Maybe you should teach it the words........[/quote]I've always liked the Happy Wanderer myself. Link to comment Share on other sites More sharing options...
Jackie Posted January 3, 2008 Author Share Posted January 3, 2008 Well I am wondering! Someone who has a petrol Scenic has indicated their car does the same thing. OK well that being the case it knocks the turbo lubricating pump theory on the head does it, so what is it? I tried it again making sure the AC and cab fan was off, noise still there as before. If I sit in the Megane with the engine off and with the radio on 198 LW and switch on the lights the tone appears as interference but no noises under the bonnet. If I turn off the lights then the tone continues, audible only on the radio, for about 60 seconds and then stops. Similar thing happens with the Scenic except the tone stops as soon as I turn off the lights. In both cases the engine had not been run for at least an hour. I suspect that this has nothing to do with the noise heard under the bonnet and must therefore be due to something else, just coincidence that the frequency sounds the same and we are dealing with two different things. Having run the engine again on the Megane I think the noise from under the bonnet after the engine has been stopped is a fuel pump of some sort. A black plastic object mounted on the bulhead near the top right and has two black fuel type pipes going to it. There is another buzzing noise towards the front left hand side of the engine and low down, which is only audible if the ignition switch is turned on but the engine not started. Cannot do this with the Scenic as there is no ignition switch other than the motor start button.I think I hate Smart Alec cars almost as much as I hate computers. Never had these things going on with my first car, an Austin 7 (Ruby), so even more puzzled now...............J Link to comment Share on other sites More sharing options...
cooperlola Posted January 3, 2008 Share Posted January 3, 2008 Mine beeps at me if I have anything on which runs off the battery when the engine is switched off but the ignition is in the halfway position and the driver's door is open. (It's a Nissan but they share a lot of bits - including the engines). This is just a warning to stop you leaving anything switched on which could flatten the battery. I take it it isn't that? Link to comment Share on other sites More sharing options...
Will Posted January 3, 2008 Share Posted January 3, 2008 Are they the models with the card rather than the key? They are highly automated, and things start up and shut down in sequence, so it may be part of the on-board electronics that you can hear. Link to comment Share on other sites More sharing options...
Jackie Posted January 3, 2008 Author Share Posted January 3, 2008 Yes it is that type and I assume there is an on-board computer of sorts that manages everything like the automatic handbrake, wipers, lights and locking etc etc etc. That is what I mean about Smart Alec cars! I don't think the Megane, being much older, has anything like that though. Having said that I quite like the Scenic, very comfortable. Still find myself reaching for a non-existent handbrake lever rather than a switch on the dashboard at traffic lights. Yes there are various warning sounds when doors are opened, lights are on and the card is still in the slot but it is none of those that I have been describing...................................J Link to comment Share on other sites More sharing options...
powerdesal Posted January 4, 2008 Share Posted January 4, 2008 Jackie, a totally off topic question here.... Your posts give me the impression that you are British, not American ( I may be wrong here), but if so why do refer to "under the hood", are your cars soft tops? Perhaps you should check under the bonnet. [:D][:D][:D] Link to comment Share on other sites More sharing options...
Jackie Posted January 4, 2008 Author Share Posted January 4, 2008 Many thanks for the correction. One is influenced by surroundings/people past and present and I look forward to any on-topic response........John"When an elephant is in trouble, even a frog will kick him."-- Hindu ProverbWhich reminds me I must lose some weight. Regarding the fit of men's pants:A guy once told me, " if there is no ball room then I can't dance." Link to comment Share on other sites More sharing options...
Hertz Posted January 20, 2008 Share Posted January 20, 2008 It is strange what modern cars get up to on their own these days - I have a Land Rover Freelander TD4 which makes a noise like a central heating boiler working when it is cold and the engine has been running, then turned off. It is caused by an auxiliary diesel-burning heater which supplements the normal in-car heating system, and runs on for three or four minutes after the engine is stopped. The first time I heard it I was so alarmed I got out of the car and looked all round it, and was even more alarmed to find steam and fumes venting from the front wheel well. This is however a normal operation in cold weather, but I dread one day coming back to it finding the fire brigade have trashed it trying to put out a non-existent fire! Link to comment Share on other sites More sharing options...
sid Posted January 20, 2008 Share Posted January 20, 2008 I can't help with the whistle but my Megane has systems controlled by the 'onboard computer'. It can be infuriating sometimes when it decides that it is, or it isn't raining, or "Hmm yes, I think it's going dark so we'll have the lights on now". As I understand it EVERYTHING is controlled by the 'box', even the windows. Instead of the window button operating directly on the winder motor, it sends a signal to the computer which then operates the windows! I found this out when the windows failed early on in my car's life. The dealer said it was a software failure. Windows XP perhaps?Sid Link to comment Share on other sites More sharing options...
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