Porsche 997 - This is engine noise normal?
Discussion
Hi just been to view a 2005 997 Carerra S. The car is in good condition but the engine is making a slight tapping noise. Is this noise normal for the 3.8 997 engine?
Any advice/tips would be much appreciated
https://youtu.be/Q0j1zt7v4nE
https://youtu.be/wxP5NggBu5A
Regards
Any advice/tips would be much appreciated
https://youtu.be/Q0j1zt7v4nE
https://youtu.be/wxP5NggBu5A
Regards
Not sure if this will help but here's my 56 plate 997.1 C4S in August last year with 71k miles. https://youtu.be/yItdLw2LPhE.
M-oeamh said:
Hi just been to view a 2005 997 Carerra S. The car is in good condition but the engine is making a slight tapping noise. Is this noise normal for the 3.8 997 engine?
Any advice/tips would be much appreciated
https://youtu.be/Q0j1zt7v4nE
https://youtu.be/wxP5NggBu5A
Regards
Nope. Walk away. By the sound of it I'd attribute it to a noisy lifter. A piston problem would be tapping at a faster clip. A tech with a stethescope though could give a listen and at least confirm if it was coming from under the camshaft cover or from a cylinder. While unlikely he might find it coming from a loose plug or possibly even an exhaust leak.Any advice/tips would be much appreciated
https://youtu.be/Q0j1zt7v4nE
https://youtu.be/wxP5NggBu5A
Regards
But you shouldn't care. That is a noise for someone else to own... Not you.
Just to add to the "random things it could be" my 996 C2 3.6 started to make a noise that made me go a bit pale...
A really metallic sounding ticking noise that rose with engine speed. Being a 996 owner, I had read to enternity about borescore and pistonslap, and was expecting the worse.
Turns out it was the exhaust manifold gasket. Fixed that and the noise dissappeared without a trace!
If you had asked me, when standing behind the engine, if the noise was anything other than an engine issue (and a bad one) I would never have believed you!
My lesson from this was that the 996 has such a bad rep that when anything happens the "its IMS/Borescore/cracked head" demons jump in and dominate your thinking. But, these are just engines, and it pays to "think cheap" and work your way up in terms of what the issue might be.
But in relation to that car, with soooo many to choose from, why risk it unless YOU are certain and THEY are providing a cost relevant discount?
A really metallic sounding ticking noise that rose with engine speed. Being a 996 owner, I had read to enternity about borescore and pistonslap, and was expecting the worse.
Turns out it was the exhaust manifold gasket. Fixed that and the noise dissappeared without a trace!
If you had asked me, when standing behind the engine, if the noise was anything other than an engine issue (and a bad one) I would never have believed you!
My lesson from this was that the 996 has such a bad rep that when anything happens the "its IMS/Borescore/cracked head" demons jump in and dominate your thinking. But, these are just engines, and it pays to "think cheap" and work your way up in terms of what the issue might be.
But in relation to that car, with soooo many to choose from, why risk it unless YOU are certain and THEY are providing a cost relevant discount?
LotusAlfaV6bloke said:
Just to add to the "random things it could be" my 996 C2 3.6 started to make a noise that made me go a bit pale...
A really metallic sounding ticking noise that rose with engine speed. Being a 996 owner, I had read to enternity about borescore and pistonslap, and was expecting the worse.
Turns out it was the exhaust manifold gasket. Fixed that and the noise dissappeared without a trace!
If you had asked me, when standing behind the engine, if the noise was anything other than an engine issue (and a bad one) I would never have believed you!
My lesson from this was that the 996 has such a bad rep that when anything happens the "its IMS/Borescore/cracked head" demons jump in and dominate your thinking. But, these are just engines, and it pays to "think cheap" and work your way up in terms of what the issue might be.
But in relation to that car, with soooo many to choose from, why risk it unless YOU are certain and THEY are providing a cost relevant discount?
Sure, were that my car I'd spend some money to determine what the source of the noise is, probably even fix it if it was fixable. But unless the buyer is a glutton for punishment, or has some crystal ball the rest of us can only dream about, assume the worst and move on.A really metallic sounding ticking noise that rose with engine speed. Being a 996 owner, I had read to enternity about borescore and pistonslap, and was expecting the worse.
Turns out it was the exhaust manifold gasket. Fixed that and the noise dissappeared without a trace!
If you had asked me, when standing behind the engine, if the noise was anything other than an engine issue (and a bad one) I would never have believed you!
My lesson from this was that the 996 has such a bad rep that when anything happens the "its IMS/Borescore/cracked head" demons jump in and dominate your thinking. But, these are just engines, and it pays to "think cheap" and work your way up in terms of what the issue might be.
But in relation to that car, with soooo many to choose from, why risk it unless YOU are certain and THEY are providing a cost relevant discount?
With used cars, and this includes naturally Porsches, there is always another car.
Taken a little out of context I have reproduced the following extract from our new technical guide to engine problems. When it goes live it links to others threads (hence the occasional number in the text which locates it) so the following is by no means an answer written specifically for this question but may contain something useful for owners to read on the subject (and saves me a lot of time).
"This is a tedious and complex subject that only affects a very small number of engines and may emanate from "something serious" or be "perfectly normal" - the potential from which often invites owners to delve into it deeper when in reality it probably isn't worth the time it takes to absorb all the possibilities.
Because it can afflict cars whose engines have never been touched since new, engines that have been rebuilt perfectly and those with nothing wrong with them - but may also be a sign of serious problems - we have tried exhaustively to indentify the cause and in the process spent thousands on changing components, road testing and stripping and rebuilding engines for inspection and even designing and manufacturing special parts - and these are our combined conclusions.
For a brief explanation - read on.
The crankshafts on all engines speed up and slow down between each firing stroke and if the tickover is slowed down and down - eventually it can be felt as a rock or shake in the engine mountings (or for engines with chain or gear camshaft drives - often in backlash through that drive system). As the revs increase there is insufficient time between firing strokes for the speeding up and slowing down of the crankshaft to move as far (or be of as great an amplitude) before the next firing stroke arrives - smoothing the result. Those used to rebuilding or tuning older engines designs will be used to adjusting the tickover screw to find a smooth tickover speed and will know that it takes very few revs to change a bad snatch into a perfectly smooth engine - but modern ECU systems rarely provide this adjustment and as a result those rebuilding different manufacturers engines often create a slight tickover noise that they cannot get rid of because they don't have the means to raise the tickover slightly (which Internet research will confirm) .
With emphasis on low emissions manufacturers try to set the slowest tickover speed and least fuel delivery they can get away with for their particular engine on tickover (and with modern ECU digital controls often arrange the tickover control revs to fall lower and lower in steps as the engine heats up - which M96 and M97 engines incorporate).
Engines where the layout has good natural balance can get away with lighter flywheels and engines with cylinders not all in a straight line can also result in lighter crankshafts.
Sports camshafts make it necessary to increase the revs for a smooth tickover but Camshafts systems that provide variable timing and/or lift help run both sports cams and better breathing at low revs and can enable manufacturers to lower tickover revs further (as in the M96/7 range)
A flat 6 layout like the 911 also provides natural opportunities to run very light crankshafts and flywheels and as it also features chain camshaft drives - is probably more prone to this problem than almost any other design layout (and the affect of chains in particular - flapping under dynamic loads can be seen by viewing (Roll-Ring Chain Tensioner videos on You Tube *77*) and you will probably not appreciate the forces involved without viewing that very useful clip).
With almost everything against it - this engine range are set for such a low tickover within the ECU when hot that anything that alters the balance of the performance from one cylinder to another - can introduce a "snatch" in that smooth running that causes chain flap and a ticking noise at one point in the crankshaft rotation - heard as a tick.
This is exacerbated in these engines by the (hydraulic chain tensioners *75*) being a less than ideal design (not containing a buffer reservoir or a spring loaded non return valve) and by the firing order resulting in a long distance between the drive chains and shaft between two firing orders.
If the noise is caused by this upset balance then it usually goes away if the revs are raised a little - or the inertia/load on the engine is increased (but not usually if it is caused by something that needs serious attention).
Increasing the load on the engine at tickover is a way to test the seriousness of the cause. Because the ECU alters the parameters to keep the tickover the right revs for the temperature pre-set - any extra load has to be matched by an increase in air flow to the engine and consequently the fuelling - and it also increases the effective weight or inertia of the rotating mass that also reduces the range and size of impulses between firing stokes. As a result, loading the drive (tiptronic gear engagement increases drive train inertia) or switching on the air-con (increases loads through the air-con pump and alternator discharge feeding the additional fans that come on) can force the ECU to open the throttle or bye pass more and in turn deliver more fuel - so if the imbalance derived from any of those systems - an increase can smooth it out due to the error becoming less proportionally. Increasing the revs also raises the oil pressure feeding the hydraulic chain tensioners.
POTENTIALLY SERIOUS CAUSES, that can upset this balance includere, scored bores, cracked cylinders, worn tappets, worn chains, reduced oil pressure (through worn crankshaft shells etc), loose valve seats, air leaks, air mass sensor faults, etc.
Symptoms for most causes are the same - a ticking noise like a tappet with too much clearance - although a scored bore can also result in the piston tapping harder at the cylinder head and crankshaft shell wear a knocking that continues as revs rise.
INNOCENT CAUSES include, carbon deposits, lose exhaust connections,, non standard exhausts, worn hydraulic chain tensioners, worn throttle pennies, blocked tickover byepass valves, worn fuel injectors, worn or loose spark plugs, etc - in other words - things that just happen to be slightly less perfect than when the car was new and just requiring a slight increase in tickover revs to eliminate (which is not normally adjustable).
We have become quite good at testing and identifying if a cause is serious or innocent but it is very difficult for those lacking the number of cars and changes we have tried and tested over many years.
There are many minor components and settings that can set off this fluctuation in tickover revs and yet the end result of an unstable tickover makes the same noise - so trying to get rid of the noise by trial and error is not viable. So once we are satisfied that the cause is not serious and if (sometimes after trying a few simple things) we cannot get rid of the noise it may unfortunately become something that an owner may just have to live with.
Innocent ticking noises on tickover have no implications for long term reliability but are frankly just irritating! (*More on this subject 76*)".
Baz
"This is a tedious and complex subject that only affects a very small number of engines and may emanate from "something serious" or be "perfectly normal" - the potential from which often invites owners to delve into it deeper when in reality it probably isn't worth the time it takes to absorb all the possibilities.
Because it can afflict cars whose engines have never been touched since new, engines that have been rebuilt perfectly and those with nothing wrong with them - but may also be a sign of serious problems - we have tried exhaustively to indentify the cause and in the process spent thousands on changing components, road testing and stripping and rebuilding engines for inspection and even designing and manufacturing special parts - and these are our combined conclusions.
For a brief explanation - read on.
The crankshafts on all engines speed up and slow down between each firing stroke and if the tickover is slowed down and down - eventually it can be felt as a rock or shake in the engine mountings (or for engines with chain or gear camshaft drives - often in backlash through that drive system). As the revs increase there is insufficient time between firing strokes for the speeding up and slowing down of the crankshaft to move as far (or be of as great an amplitude) before the next firing stroke arrives - smoothing the result. Those used to rebuilding or tuning older engines designs will be used to adjusting the tickover screw to find a smooth tickover speed and will know that it takes very few revs to change a bad snatch into a perfectly smooth engine - but modern ECU systems rarely provide this adjustment and as a result those rebuilding different manufacturers engines often create a slight tickover noise that they cannot get rid of because they don't have the means to raise the tickover slightly (which Internet research will confirm) .
With emphasis on low emissions manufacturers try to set the slowest tickover speed and least fuel delivery they can get away with for their particular engine on tickover (and with modern ECU digital controls often arrange the tickover control revs to fall lower and lower in steps as the engine heats up - which M96 and M97 engines incorporate).
Engines where the layout has good natural balance can get away with lighter flywheels and engines with cylinders not all in a straight line can also result in lighter crankshafts.
Sports camshafts make it necessary to increase the revs for a smooth tickover but Camshafts systems that provide variable timing and/or lift help run both sports cams and better breathing at low revs and can enable manufacturers to lower tickover revs further (as in the M96/7 range)
A flat 6 layout like the 911 also provides natural opportunities to run very light crankshafts and flywheels and as it also features chain camshaft drives - is probably more prone to this problem than almost any other design layout (and the affect of chains in particular - flapping under dynamic loads can be seen by viewing (Roll-Ring Chain Tensioner videos on You Tube *77*) and you will probably not appreciate the forces involved without viewing that very useful clip).
With almost everything against it - this engine range are set for such a low tickover within the ECU when hot that anything that alters the balance of the performance from one cylinder to another - can introduce a "snatch" in that smooth running that causes chain flap and a ticking noise at one point in the crankshaft rotation - heard as a tick.
This is exacerbated in these engines by the (hydraulic chain tensioners *75*) being a less than ideal design (not containing a buffer reservoir or a spring loaded non return valve) and by the firing order resulting in a long distance between the drive chains and shaft between two firing orders.
If the noise is caused by this upset balance then it usually goes away if the revs are raised a little - or the inertia/load on the engine is increased (but not usually if it is caused by something that needs serious attention).
Increasing the load on the engine at tickover is a way to test the seriousness of the cause. Because the ECU alters the parameters to keep the tickover the right revs for the temperature pre-set - any extra load has to be matched by an increase in air flow to the engine and consequently the fuelling - and it also increases the effective weight or inertia of the rotating mass that also reduces the range and size of impulses between firing stokes. As a result, loading the drive (tiptronic gear engagement increases drive train inertia) or switching on the air-con (increases loads through the air-con pump and alternator discharge feeding the additional fans that come on) can force the ECU to open the throttle or bye pass more and in turn deliver more fuel - so if the imbalance derived from any of those systems - an increase can smooth it out due to the error becoming less proportionally. Increasing the revs also raises the oil pressure feeding the hydraulic chain tensioners.
POTENTIALLY SERIOUS CAUSES, that can upset this balance includere, scored bores, cracked cylinders, worn tappets, worn chains, reduced oil pressure (through worn crankshaft shells etc), loose valve seats, air leaks, air mass sensor faults, etc.
Symptoms for most causes are the same - a ticking noise like a tappet with too much clearance - although a scored bore can also result in the piston tapping harder at the cylinder head and crankshaft shell wear a knocking that continues as revs rise.
INNOCENT CAUSES include, carbon deposits, lose exhaust connections,, non standard exhausts, worn hydraulic chain tensioners, worn throttle pennies, blocked tickover byepass valves, worn fuel injectors, worn or loose spark plugs, etc - in other words - things that just happen to be slightly less perfect than when the car was new and just requiring a slight increase in tickover revs to eliminate (which is not normally adjustable).
We have become quite good at testing and identifying if a cause is serious or innocent but it is very difficult for those lacking the number of cars and changes we have tried and tested over many years.
There are many minor components and settings that can set off this fluctuation in tickover revs and yet the end result of an unstable tickover makes the same noise - so trying to get rid of the noise by trial and error is not viable. So once we are satisfied that the cause is not serious and if (sometimes after trying a few simple things) we cannot get rid of the noise it may unfortunately become something that an owner may just have to live with.
Innocent ticking noises on tickover have no implications for long term reliability but are frankly just irritating! (*More on this subject 76*)".
Baz
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