Ax 998cc Motronic Single Point Injection, 4 speed.
Aux belt replaced three weeks ago, not re-tensioned since.
This morning - 60mph on motorway, start hearing funny "knocking" sound - very fast, in direct relation to the speed of the engine.
More pronounced on a slight throttle - becomes muted on both no and full throttle.
Performance does not seem to be affected.
Noise there at idle, very noisy when revved, still there with clutch in , and neutral.
No smoke from the exhaust.
Checked the oil level - low but not as low as min level. Topped up with 2L 15W40.
Noise still there.
My thoughts are something as simple as..
a) The aux belt is flapping ( although tension seems ok but needs tightening slightly as it sometimes squeals ).
b) Something has got in the cam-belt covers.
c) The cam-belt is frayed, and it's "whipping" the covers.
d) somethig else.
My reasoning for the above is that the noise is a bit like a jack-hammer, but imagine a plastic sound rather than a metal sound...
Does that make sense to anyone ???
Strange AX sound..
Moderator: RichardW
-
RichardW
- Forum Treasurer
- Posts: 10872
- Joined: 07 Aug 2002, 17:12
- Location: United Kingdom
- My Cars: MK2 '17 C4GP 1.6 BlueHDi 120
'13 3008 1.6 HDi GripControl - x 996
Oh, go on then, since nobody else is going to say it I will. Big End?
Did you really mean TWO LITRES of oil? My guess is it's now way over the top, or or was way below the min before.
Could also be that you've blown a set of diodes in the alternator - this can make a knocking noise as the alternator comes on/off load.
Difficult to tell without hearing it - have a good look round the engine bay first for anything obvious. Maybe the crankshaft pulley has come loose, or the auxiliary belt tensioner has come loose and is rocking backwards and forwards.
Not much help really.
You're not having much luck over there at the moment, are you?
Richard
Did you really mean TWO LITRES of oil? My guess is it's now way over the top, or or was way below the min before.
Could also be that you've blown a set of diodes in the alternator - this can make a knocking noise as the alternator comes on/off load.
Difficult to tell without hearing it - have a good look round the engine bay first for anything obvious. Maybe the crankshaft pulley has come loose, or the auxiliary belt tensioner has come loose and is rocking backwards and forwards.
Not much help really.
You're not having much luck over there at the moment, are you?
Richard
-
Jon
hm, bit worried about having to put 2 litres of oil in to top up, but....
Last week my neighbour with the infamous Berlingo van came to see me about a "funny noise" it was making. Seemed to be from the alternator area. So took the drive belt off to eliminate the belt tensioner and alternator from our enquiries, noise still there!
Found that the crank pulley had broken, there was just enough of it left to spin the alternator! Said pulley removed from a scrap 306 and fitted, which solved the problem.
Hope that you are lucky like this.
[:p]
Last week my neighbour with the infamous Berlingo van came to see me about a "funny noise" it was making. Seemed to be from the alternator area. So took the drive belt off to eliminate the belt tensioner and alternator from our enquiries, noise still there!
Found that the crank pulley had broken, there was just enough of it left to spin the alternator! Said pulley removed from a scrap 306 and fitted, which solved the problem.
Hope that you are lucky like this.
[:p]
Jon raises an interesting point here; the pulley in question is referred to as an "harmonic balance" & is effectively a pulley held to its boss via a rubber medium.
Over here they rebush them using a poly material which supposedly lasts for ever. The BX 16Vs had a habit of dropping the occasional one & the symptoms I have been told range from a sound like the slipping belt to a tinny rattle to a noise not dissimilar to the one you describe.
Might be a good starting point.
I'd be inclined at this stage to discount the oil useage as being a contributing factor to the symptoms as I feel it may just be adding a distraction totally unconnected at this stage.
Alan S
Over here they rebush them using a poly material which supposedly lasts for ever. The BX 16Vs had a habit of dropping the occasional one & the symptoms I have been told range from a sound like the slipping belt to a tinny rattle to a noise not dissimilar to the one you describe.
Might be a good starting point.
I'd be inclined at this stage to discount the oil useage as being a contributing factor to the symptoms as I feel it may just be adding a distraction totally unconnected at this stage.
Alan S
-
Jon
Well, it goes from bad to worse.
Got home tonight, need the tools from the Xantia project, open the car, pull the bonnet lever ( they're in the battery tray ), and the lever comes out of it's mounting in my hand. Having a feel indicates the cable is still attached.
Anyway, got some other tools, and first of all took off the aux belt - noise still there. No obvious signs of oil leaks.
Got other half to rev the engine, felt the bottom, no real vibes.
Put my hand on the cylinder head cover, and felt knocking bang in-time with the noise.
I will take your theory on-board. Is it also possible that I could be looking at a broken cam-shaft, eg - only the valves on three cylinders are working, and the noise I'm hearing is the romantic meeting of piston and cylinder ? I have noticed a slight puff of smoke on initial startup which wasn't there before ( although I suppose this could be over-full oil ? )
Next step is to let the engine cool a little ( it's red hot ), and take the cylinder cover off, and look at the cam.
So, Xantia out of action, can't get into bonnet now, and the AX is poorly but driveable.
Think I may go and get that banger tomorrow, can't be without a car, never mind two !
Got home tonight, need the tools from the Xantia project, open the car, pull the bonnet lever ( they're in the battery tray ), and the lever comes out of it's mounting in my hand. Having a feel indicates the cable is still attached.
Anyway, got some other tools, and first of all took off the aux belt - noise still there. No obvious signs of oil leaks.
Got other half to rev the engine, felt the bottom, no real vibes.
Put my hand on the cylinder head cover, and felt knocking bang in-time with the noise.
I will take your theory on-board. Is it also possible that I could be looking at a broken cam-shaft, eg - only the valves on three cylinders are working, and the noise I'm hearing is the romantic meeting of piston and cylinder ? I have noticed a slight puff of smoke on initial startup which wasn't there before ( although I suppose this could be over-full oil ? )
Next step is to let the engine cool a little ( it's red hot ), and take the cylinder cover off, and look at the cam.
So, Xantia out of action, can't get into bonnet now, and the AX is poorly but driveable.
Think I may go and get that banger tomorrow, can't be without a car, never mind two !
Yep, that's the theory that I'm working on.
I took the cover off, and lifted up the arms gently ( without doing a full test ), and there was definite movement which I would call excessive, so I've just bought another set of feelers ( the others are under the xantia bonnet ! ), and will check them tomorrow.
If the cam is worn excessively, I presume the cure is 'simply' a new cam - as machining the current one would mean adjustments all over the place ?
It's driveable albeit noisy at the moment. I checked the oil level earlier when it had stood, it was just above the minimum ( that's with the 2L put in earlier ). I've since poured lots of oil over the whole cam, and it was quiet for a short while, and then got noisy once it had been run at speed for a short while.
I took the cover off, and lifted up the arms gently ( without doing a full test ), and there was definite movement which I would call excessive, so I've just bought another set of feelers ( the others are under the xantia bonnet ! ), and will check them tomorrow.
If the cam is worn excessively, I presume the cure is 'simply' a new cam - as machining the current one would mean adjustments all over the place ?
It's driveable albeit noisy at the moment. I checked the oil level earlier when it had stood, it was just above the minimum ( that's with the 2L put in earlier ). I've since poured lots of oil over the whole cam, and it was quiet for a short while, and then got noisy once it had been run at speed for a short while.
This is only a theory as I understand that only about 50 AXs were ever sold over here so they're not all that common, but I wonder if this engine has hydraulic valve lifters & if so if a couple are stuck due to it running short on oil when it did?
The reason I ask is that at present we are doing a stem to stern rebuild on a BX 16V motor & were advised to "bleed" or "burp" the small pistons inside the actual camfollowers when we began reassembly.
When investigated further, it was found that whilst some where pliable, others were rock hard & we were told that the engine would rattle, miss & possibly may not even start in extreme cases where several were affected. I suppose the rule of thumb could be if the tappets are of the adjustable type, all bets are off unless one of the adjustments has come loose.
This oil is becoming a mystery too isn't it? If you filled the oil back to the right level when you discovered it was down, and if it's now down again by another 2 litres, you should be laying down a pretty good sort of a smoke screen or noticing that following vehicles are all sliding off the road for no logical reason [:0][}:)]...where's it going???
Also, when did it last have an oil change & new filter in case its blocking & lowering its circulation pressure & volume & hence lubricating abilities.
Alan S
The reason I ask is that at present we are doing a stem to stern rebuild on a BX 16V motor & were advised to "bleed" or "burp" the small pistons inside the actual camfollowers when we began reassembly.
When investigated further, it was found that whilst some where pliable, others were rock hard & we were told that the engine would rattle, miss & possibly may not even start in extreme cases where several were affected. I suppose the rule of thumb could be if the tappets are of the adjustable type, all bets are off unless one of the adjustments has come loose.
This oil is becoming a mystery too isn't it? If you filled the oil back to the right level when you discovered it was down, and if it's now down again by another 2 litres, you should be laying down a pretty good sort of a smoke screen or noticing that following vehicles are all sliding off the road for no logical reason [:0][}:)]...where's it going???
Also, when did it last have an oil change & new filter in case its blocking & lowering its circulation pressure & volume & hence lubricating abilities.
Alan S
The ax engine doesnt have Hydraulic valve lifters as the engine in question is the tu engine, which is also fitted to my zx in 1.4 form. the valve clearances are adjusted manually by nut and screw job. I have done this before on my zx. But you find that some of the nuts a pain to budge as i did. But I decided to leave it as the clearance was only a little loose and could live with a little tap tap tap tap.
I would say that your camshaft has been damaged through the engines sudden hunger for oil.
However regarding your oil consumption and the noise, it could also be that one of the piston rings have broken, which is know letting oil into the combustion chambers, therefore leading to an increase in consumption. But you dont mention any smoke while driving or decrease in performance. So i think its valve train related i.e. camshaft and valve stem oil seals.
I would say that your camshaft has been damaged through the engines sudden hunger for oil.
However regarding your oil consumption and the noise, it could also be that one of the piston rings have broken, which is know letting oil into the combustion chambers, therefore leading to an increase in consumption. But you dont mention any smoke while driving or decrease in performance. So i think its valve train related i.e. camshaft and valve stem oil seals.
When you look at your camshaft you should if possible have a look at the rockers as well. There is a carefully calculated set of silencing curves that are applied to both and on many engines noise was in fact largely caused by wear on the rocker faces as well as the camshaft. Unfortunately I think your rockers are all on one shaft, rather than the cheaper but easier arrangement used on some Fords and I think earlier Peugeots.
I don't know how much you wish to spend on this car. My wife had an elderly Mini (pushrod valves of course) with a worn rocker setup and I used to adjust the valves with a dial gauge so that I could get an accurate reading of what was happening as everything was far too worn to give good results with a feeler gauge. Machine Mart sell dial gauges for about £15 but mounting it could be interesting as usually a magnetic stand is used. Mini heads are cast iron - AX heads are non-magnetic alloy.
I would be concerned as to where your oil went. 2 litres to bring it to the low mark is a lot. How long did it take to get to that stage? - ie when was it last checked? - Is it blowing oil out of all its joints (suspect rings) - is the breather clear? probably yes but worth a look!
jeremy
I don't know how much you wish to spend on this car. My wife had an elderly Mini (pushrod valves of course) with a worn rocker setup and I used to adjust the valves with a dial gauge so that I could get an accurate reading of what was happening as everything was far too worn to give good results with a feeler gauge. Machine Mart sell dial gauges for about £15 but mounting it could be interesting as usually a magnetic stand is used. Mini heads are cast iron - AX heads are non-magnetic alloy.
I would be concerned as to where your oil went. 2 litres to bring it to the low mark is a lot. How long did it take to get to that stage? - ie when was it last checked? - Is it blowing oil out of all its joints (suspect rings) - is the breather clear? probably yes but worth a look!
jeremy
The car has done 104k miles, and we've had it since 100k. Used to belong to a member of the family who had it serviced, but wanted another car for 'reliability' reasons. I think the only major problem he had was it not starting when warm, which we have fixed ( coolant temp sensor ).
I last checked the oil level about three weeks ago, when it was above minimum, so that was fine. We have not done any oil of filter changes yet.
The service book is stamped to a certain degree, although the type of person and profession of this relative would lead me to believe it would have been serviced regularly.
The cover breather hose was slightly gunged up, but not totally restricted. I have also run the engine with the cover off, and oil is being sprayed up from the block.
Going to check and adjust the clearances this morning.
I last checked the oil level about three weeks ago, when it was above minimum, so that was fine. We have not done any oil of filter changes yet.
The service book is stamped to a certain degree, although the type of person and profession of this relative would lead me to believe it would have been serviced regularly.
The cover breather hose was slightly gunged up, but not totally restricted. I have also run the engine with the cover off, and oil is being sprayed up from the block.
Going to check and adjust the clearances this morning.
If the rings have gone you will know when you remove the rocker cover, and probably before you remove it. This may sound daft but it will fume and I mean fume heavily and unmistakeably, not just the odd waft of fumes but real high pressure stuff often accompanied by a pulsing noise when the filler cap is removed. You can do a compression test which will confirm things with a low reading on one or more cylinders.
You can get a similar effect if the head gasket fails but I think the TU engine is a wet-liner engine which means that if there is a leakage from the bore it will inevietably get into the cooling system vausing pressurisation, coolant loss etc. If it was not a wet liner engine it is possible to get a leak in such a place that it communicates to an oil return way from the head and causes crankcase pressurisation and leaves the cooling alone. (My TD BX went between 2 bores only - lost 2 cylinders but no other symptoms!)
So I would suggest that you do a compression test soon before spending loads of time checking valve clearances etc. If all is ok - well it may still burn oil but not in that great a quantity.
104K on a well serviced engine doesn't sound much of a mileage does it - especially when compared with some of themileages claimed here. This is however the smallest engine available in the AX range and so will probably have been worked hard for a fair proportion of its life while to work many of the larger engines hard for long periods you would be going enormously fast and so inevietably these engines spend most of their life lightly loaded. This I'm sure has a direct bearing on engine life.
Jeremy
You can get a similar effect if the head gasket fails but I think the TU engine is a wet-liner engine which means that if there is a leakage from the bore it will inevietably get into the cooling system vausing pressurisation, coolant loss etc. If it was not a wet liner engine it is possible to get a leak in such a place that it communicates to an oil return way from the head and causes crankcase pressurisation and leaves the cooling alone. (My TD BX went between 2 bores only - lost 2 cylinders but no other symptoms!)
So I would suggest that you do a compression test soon before spending loads of time checking valve clearances etc. If all is ok - well it may still burn oil but not in that great a quantity.
104K on a well serviced engine doesn't sound much of a mileage does it - especially when compared with some of themileages claimed here. This is however the smallest engine available in the AX range and so will probably have been worked hard for a fair proportion of its life while to work many of the larger engines hard for long periods you would be going enormously fast and so inevietably these engines spend most of their life lightly loaded. This I'm sure has a direct bearing on engine life.
Jeremy