I have a 1998 Xantia 1.9 TD.
Recently, when starting from cold, there is a rattle from the front of the car for about the first mile of a journey. The rattle does not sound like it is from the engine more like it is something that has come loose and is vibrating. However, once the car starts to get warm it dissapears. I have had the bonnet up and held all of the parts (without risk of losing body parts), fans, radiator, undertray that are likely to be the cause but none seem to be.
Any ideas?
Xantia Rattle
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How long have you had the car and has it always had this rattle or has it started recently.
A cold indirect diesel such as these do make a slightly different sound when cold started, this is down to the injection timing advance, it causes the diesel knock to become much more pronounced giving it a sharp metalic sound, this dissapears instantly as the engine reaches a preset temperature and the ECU switches off the valve controling the vacuum to the timing advance diaphragm.
Watch the timing advance vacuum unit and cable as the cold engine warms up, if the rattle stops when the vacuum unit dissengages then its merely the sound of combustion, allbeit a different sound.
Dave
A cold indirect diesel such as these do make a slightly different sound when cold started, this is down to the injection timing advance, it causes the diesel knock to become much more pronounced giving it a sharp metalic sound, this dissapears instantly as the engine reaches a preset temperature and the ECU switches off the valve controling the vacuum to the timing advance diaphragm.
Watch the timing advance vacuum unit and cable as the cold engine warms up, if the rattle stops when the vacuum unit dissengages then its merely the sound of combustion, allbeit a different sound.
Dave
Thanks for the tips. I hadn't even considered that it could be the auxilliary drive belt (why are they still called 'fan belts'?).
I will check it out when the weather dries up. The weather is awful here in Manchester at the moment.
When I check the belt, what am I looking for? Slackness, wear, fraying or what?
I don't think that it is the sound of combustion as I have had the car from new and have only heard this sound recently. The sound appears to fluctuate even though the engine speed is constant as if it is a harmonic vibration.
The cam belt was changed at 36000 miles earlier this year and I am about to do the 42000 mile service so I may change the auxilliary belt at the same time. Is it a big job?
I will check it out when the weather dries up. The weather is awful here in Manchester at the moment.
When I check the belt, what am I looking for? Slackness, wear, fraying or what?
I don't think that it is the sound of combustion as I have had the car from new and have only heard this sound recently. The sound appears to fluctuate even though the engine speed is constant as if it is a harmonic vibration.
The cam belt was changed at 36000 miles earlier this year and I am about to do the 42000 mile service so I may change the auxilliary belt at the same time. Is it a big job?
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Maybe a good idea, if not to change the belt, at least examine it. You'll need to jack up, remove the off-side front wheel and take off the plastic cover at the back of the wheel arch. Engines with air-con have different belts to those without. Some engines have a manual adjustment, others have an automatic tensioner. For manual adjustment, Citroen recommend that an electronic Seem meter should be used, but adjustment can be done by using thumb pressure so as to have about 5mm of deflection on the longest run of belt. A belt which is too loose will cause squeal, on the other hand, if it's too tight will damage the alternator bearings.
Whilst looking for a missing accelerator clip, see other post, I had the engine running at night to try to dislodge it.
Whilst looking at the auxilliary drive belt I noticed that when the rattle noise occured the tensioner pully that is visable from the front of the engine bay vibrated (the shiney surface caught the lead lamb beam just right). So this is the cause of my problem and thanks to those that suggested it. I was quite sceptical.
The question now is, will a new auxilliary drive belt cure the problem or will I also need a new tensioner pully? I assume that with an old cold belt when it wraps around the tensioner pulley the opposite way, flat side to pully, to the other pulleys it is not supple enough to bend in a perfect radius, hence the vibration. Am I correct?
Richard Green
Whilst looking at the auxilliary drive belt I noticed that when the rattle noise occured the tensioner pully that is visable from the front of the engine bay vibrated (the shiney surface caught the lead lamb beam just right). So this is the cause of my problem and thanks to those that suggested it. I was quite sceptical.
The question now is, will a new auxilliary drive belt cure the problem or will I also need a new tensioner pully? I assume that with an old cold belt when it wraps around the tensioner pulley the opposite way, flat side to pully, to the other pulleys it is not supple enough to bend in a perfect radius, hence the vibration. Am I correct?
Richard Green
Simplest way to check a belt of course is to lightly spray with WD40 (looks of shock & horror )<img src=icon_smile_shock.gif border=0 align=middle> and see if that makes the noise disappear. I have a CX that can sound like the motors going to drop out of it somedays. I just grab the can, give the belt a squirt and the noise disappears. I'll replace the belt as soon as it sticks me up out on a deserted road at 1 o'clock on a stormy night no doubt<img src=icon_smile_big.gif border=0 align=middle>
Alan S
Alan S