peugeot 306 knocking noise

Got a 6 year old 306 (60k miles) and recently i noticed a "knocking" noise
coming from the front of the car when accelerating hard and generally when
the engine is under load - it's quite loud going up a steep hill for
example. There's no noise when idle or if I rev the engine without the
clutch engaged. Any ideas?

 

It could be the exhaust manifold.
John

 

Is it diesel or petrol?

My diesel (HDI) does exactly this .... on going up hill it makes a knocking
sound (not very loud but noticable) or when accerating hard (i.e. in forth
gear accellerating whilst joining a motorway) When the engine gets to
exactly 3000rpm on mine the noise stops completly

 

Sorry, I forgot to mention...It's petrol.
Actually the noise is really noticeable when driving close to something that
reflects sound (like another car, tunnel walls, hill side and so on) - most
of the time it's just a faint knocking metal-on-metal noise. It sounds
really really bad when the sound is reflected back though, like two bits of
metal hitting/scraping against each other. I noticed the same kind of noise
when I'm about to move off in first gear but don't really give it enough gas
(almost stalling it).

The clutch doesn't feel like it's going. Having said that, I've had the car
for 3 years and have yet to change it...To be honest I'm kinda scared it's
the gearbox. Could it be that the gearbox might be leaking oil? How can I
check? (I don't have a driveway so it's impossible to tell if I've got a
leak by just looking at the ground).

 

From what you say it doesnt sound like a gearbox prob, I was just
saying that cos from what u say it seems odd u can hear it in a
straight line. When you say scraping noise i sort of thought of
brakes and warped discs or drum.

When you hear the noise can u feel anything through your pedals or
steering wheel? Normally when a CV joint goes you can feel it when
you accelerate round corners, although not all the time but most of
the time u can.

when you change gear does the noise get slower until you have to
change gear again or does it just get faster and faster?

sorry for all the questions but its kinda hard to diagnose this
without hearing it. Most knocking noises are either when turning a
corner or something quite big has gone in the engine. I wouldnt think
exhaust banging off the car because when that vibrates it tends to get
bad at about 2500 to 3000 revs and then because of the vibration it
tends to go away and the whole car makes a humming noise!

scott

 

I had a problem with mine where the car would produce a bloody awful
loud rattling noise when the engine was under load. It did it when you
accelerated anything more than gently and was more pronounced going
uphill. As with you it also was fine when just revving the engine.

I put it into a garage because past very simple things I know nothing
about cars and they said it was to do with the exhaust. They said
something like 2 of the exhausts sections weren't quite totally aligned
up and that this bit vibrating was the cause of the noise. As I said,
I'm no expert and might not have remember what they said properly so
this might not be quite right, but it was definitely exhaust related and
it only cost me an hour's labour to diagnose and fix.

Gavin

 

It won't be the clutch or gearbox.

If its a regular knock with every turn of the engine which increases
with engine revs, and gets worse under load its likely to be a big
end, which is bad news.

If its a higher pitch metalic clicking rather than a knock, the
tappets need adjusting, but you would normally hear this even on
tick-over.

Should really get big-end trouble with such a low mileage unless its
been driven hard or without oil.

 

Looks like I'll have to take it to a garage Prob is i'll be in france for
a while and don't speak french LOL

Anyway, got a few other people to give me their opinion on what it sounds
like (what kinda noise it is) and none
of them could agree I got various descriptions from "harsh, scarping
noise", "tick/scrape", "knock/scrape" to
"faint knocking". All I can say is that it's rare when it's just me in the
car (basically, only when going uphill and accelerating hard)
but it happens a lot more with other people in the car (never heard it in
first gear, but it does it in all others).
If it's the big end, is it likely the engine's burning oil? Because I
checked the levels and it doesn't appear to be the case.
Cheers guys.