Xantia - funny noise

KAD · Post by **KAD** » 19 Nov 2002, 01:33

1994 Xantia 1.9 TD
It runs and drives OK but when I rev the engine beyond 2500 - 3000
it makes a funny noise like a resonant flapping/drumming from the
engine. It sounds like maybe the intercooler plastic pipes are
vibrating on boost or something. On the odd occasion I managed to get
rid of the noise, but I don't know what was causing it. I thought I'd fixed by using cable ties on everything, but the noise returned.
I've checked the whole induction system, (which has a lot of possible
rattles) and it looks OK. The rest of the engine is spot on and it's not the cam or alternator belt. Maybe it's something to do with the hydraulics or cooling system, or perhaps an engine mounting. It's not
a major problem, but I don't like it and it shouldn't do it.
Suggestions ???

nick · Post by **nick** » 20 Nov 2002, 05:45

When the accumulator sphere was going flat on my Xantia I used to get a sort of rattling noise when the engine was revved. Just the hydraulic system repressurising, which it has to do much more often if the accumulator's flat.
The noise you get on Xantias seems quite different to the straightforward 'click' BX's make when they've got this problem. Its a difficult noise to describe, but I think the best description I've heard was 'like someone twanging a wooden ruler on a school desk'!
Nick

KAD · Post by **KAD** » 21 Nov 2002, 01:32

I think I've found the problem now.
The oil filler has a breather pipe connected to the inlet
manifold rubber ducting and at the end there is a round valve.
I took this off and I can blow through it both ways, that has
to be wrong, I'm sure it should be a one way valve. As it is,
turbo boost pressure will go down the filler neck and into the
sump, which I'm sure would cause the problem.
A new valve is on order. I will confirm if this fixed the
problem.

Dave Burns · Post by **Dave Burns** » 21 Nov 2002, 03:03

Sorry to dissapoint but the crankcase breather goes to the induction side of the turbo, there is no positive pressure in that part of the intake ducting, nor is it possible for boost pressure to get into the sump.
Dave

KAD · Post by **KAD** » 21 Nov 2002, 17:11

Yes you are right, I was talking garbage there. But it does
beg the question; what is the regulator for?

stevenlizuk · Post by **stevenlizuk** » 23 Nov 2002, 18:53

hi all
my xantia also recently started making a hollow rattling noise on starting which then faded in and out. this turned out to be the drive belt tensioner. might be worth a look?
steve k
steve kerr

KAD · Post by **KAD** » 26 Nov 2002, 00:07

No, this noise (hard to put into words) only appears when
the engine is under load. It's OK when revved statically. I,m
thinking maybe something catching on the lower, rear engine
mount, that means crawling underneath so I'm trying to think of
something else that's easier to get at !!

nick · Post by **nick** » 27 Nov 2002, 05:12

Does it do this every time its revved under load, or only occasionally?

KAD · Post by **KAD** » 28 Nov 2002, 23:48

It does it all the time as I have described. But for a short
while once, it did go away.
Edited by - KAD on 28 Nov 2002 18:49:38

nick · Post by **nick** » 29 Nov 2002, 22:48

Engine noises can sometimes be located by using a piece of flexible pipe as a sort of stethoscope, but as it only does it under load you may have to find a very small person who's prepared to travel under the bonnet for a while <img src=icon_smile_wink.gif border=0 align=middle>, or use a rolling road.
Alternatively, all I can suggest is where possible remove ancilliary things like intercooler pipework, alternator drivebelt etc, one by one, and try driving for a short distance with each removed to see if it cures it.
Thats pretty much what I had to do when my Xantia started making an annoying whistling noise on acceleration. Turned out to be the inlet manifold gasket, but it took me weeks to find it.
Nick

KAD · Post by **KAD** » 19 Feb 2003, 01:28

I have reduced this noise by replacing the old soft and squidgy
lower rear engine mount, the one which is near the drive shaft. It was not a fun job to do, but it only cost £13. The old item allowed the engine to twist back too far under load
and I guess things were coming into contact and making noise because of that. It has also taken away a slight 'wobble' which I had noticed under light load. It has made the car feel altogether more solid.
That lower mount takes a lot of punishment and the old one had done so for 170,000 miles....not too bad I suppose.