1000-2000 RPM Engine Knock

[djt992]

Hey everyone,

For the past few months my engine has begun making a slight knocking sound. Sometimes its worse than others but has steadily been getting louder recently. Most people wouldn't notice it but I do since I drive the car everyday and know how it used to sound. The car has never really run smoothly on idle and kindof misses everso slightly and when held at certain revs such as 3000 you can hear a light popping noise from the exhaust as if the engine is very slightly miss firing. The car has no loss of power however never seems to run quite right.

This knocking noise appears to be irregular and does it most between 1000-2000 RPM. Heard best at around 1700rpm. I can't hear it very much from the engine bay but can hear it better inside the car. It seemed to start after I did an oil/filters/plugs change about 2 months ago and has steadily got worse. Strange thing is it doesn't make any noise when cold and runs fine, but give it about 2 minutes and it will start a quiet knocking.

Any ideas?? Thanks

[yassa]

bottom end, its fucked, might get away with changing the shells but you'll be better off getting a new engine

[Furioman]

does sound like death rattle, no point changing the shells, journals will be scored will fuck the new shells in no time. rather easy to check just whip of the sump and undo the rod caps.

but as yassa said probably easier getting another engine

[djt992]

AHh great!!

Off to the crusher then. Ploughed wayy too much money into it! Piece of shit.

[Cam]

Sounds like its not firing on all 4 smoothly try change the coilpack..

[unreal106]

have you checked all the plugs are tight and gapped correctly?

[chinkostu]

Try coilpack and check plugs first. My vtr used to have a miss at 3k revs, really bad on motorways as you would feel it. Coilpack eventually shat itself

[atspeedracing]

take it to a local garage and have a mechanic inspect it/listen to it first.

[djt992]

Thanks for all the replies. Probably best I get a garage to look so I'm taking it to Ktech tomorrow to see what they make of it. I'll get back with an update soon. :)

[vtrjunky]

make sure the plugs are tight my vtr and my vts have a habbit of spiting plugs now and then after a good thrashing on the track

[djt992]

Quick update:

Have since taken my car to k-tech for them to have a listen and they couldn't identify what the noise was since it was so quiet. They said I have a missfire going on though and can hear it running badly from the exhaust sound.

I have since tried changing the spark plugs and coil pack with no change :/

I also mentioned to them that when I had my MOT a while back, my emissions were REALLY high (3 times higher than they should be). They reckoned that its to do with fueling and that it runs smooth when cold because of the rich mixture and then starts running rough as it gets warm. They were confident it wasn't anything from the lower end.

Any ideas where to go from here? Would a faulty lambda sensor maybe cause this missfire/knocking? Or maybe a new cat?

Thanks.

[wadoryu]

Fucked cat and a vacuum leak. Fix them.

[unreal106]

It sounds like coolant temp sensor on the thermostat housing as this comes in as the car gets warm

[m4tt274]

needs B8s

[Gudza]

Quick update:

Have since taken my car to k-tech for them to have a listen and they couldn't identify what the noise was since it was so quiet. They said I have a missfire going on though and can hear it running badly from the exhaust sound.

I have since tried changing the spark plugs and coil pack with no change :/

I also mentioned to them that when I had my MOT a while back, my emissions were REALLY high (3 times higher than they should be). They reckoned that its to do with fueling and that it runs smooth when cold because of the rich mixture and then starts running rough as it gets warm. They were confident it wasn't anything from the lower end.

Any ideas where to go from here? Would a faulty lambda sensor maybe cause this missfire/knocking? Or maybe a new cat?

Thanks.

What was the problem? The problem has been solved? If yes, can u tell me the solution?

[CedricSaxo]

I know this is a really old post but I would love to hear what it was too.

[Gabbastard]

this was a problem on later L4 emissions alloy blocks, cured by plastigauging and fitting slightly "oversized" upper shells.

[Chipwizards]

Could also have been a loose spark plug, I've had that enough times with customer's cars.

[axsaxoman]

this was a problem on later L4 emissions alloy blocks, cured by plastigauging and fitting slightly "oversized" upper shells.

also happenedwith some of the 1.6 cast iron engines ---same cue
to be honest it never caused a problem with engine ,just and unwanted rubble at some rpms

[CedricSaxo]

this was a problem on later L4 emissions alloy blocks, cured by plastigauging and fitting slightly "oversized" upper shells.

I have been told this by a Citroen Master Tech. Unfortunately after I had my bearings replaced (standard size) the noise was still there as before. You seem to know your stuff, do I need to pay to have this repair redone as you described?

[axsaxoman]

I have been told this by a Citroen Master Tech. Unfortunately after I had my bearings replaced (standard size) the noise was still there as before. You seem to know your stuff, do I need to pay to have this repair redone as you described?

your bearings must have been non genuine shells .as citroen do not make a set of shells for the crankshaft main brgs ,only for the con rods -- you have to plasti gauge and then pick the upper shells to suit and order them individually
If your oil pressure is 4bar at 3000rpm -then its not a real problem -just a crank rubble which will never cause any problem