DB7 V12 engine tapping noise
Discussion
This is quite a common fault it seems.
Nothing major but very annoying and it now seems a possible solution has been unearthed.
""
It's amazing what certified mechanical engineer can find out in 2 days and not 6 weeks. It is a fault that is caused from a lack of oil pressure while car is idling, and exists in quite a few DB7 2002 -2003.
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The issue was oil pressure! After reading the Works Book, and running a diagnostic, He found out that there was insufficient oil pressure and made the proper adjustments.
""
((edited to remove unproven allegations))
Nothing major but very annoying and it now seems a possible solution has been unearthed.
""
It's amazing what certified mechanical engineer can find out in 2 days and not 6 weeks. It is a fault that is caused from a lack of oil pressure while car is idling, and exists in quite a few DB7 2002 -2003.
""
The issue was oil pressure! After reading the Works Book, and running a diagnostic, He found out that there was insufficient oil pressure and made the proper adjustments.
""
((edited to remove unproven allegations))
Edited by GTDB7 on Friday 23 November 15:20
The above are snippets credited from the AMOC forum.
AM didn't help the guy in question who eventually took it to another mechanic who quickly figured out the oil pressure was too low at idle.
Once adjusted the problem went away.
Funny how it's only affected on 2002 - 2003 models, and I wonder if Aston didn't know about this and quietly fixed it in-house on newer engine builds.
I'd be VERY interested as to what is involved to adjust the Oil Pressure at idle speeds.
AM didn't help the guy in question who eventually took it to another mechanic who quickly figured out the oil pressure was too low at idle.
Once adjusted the problem went away.
Funny how it's only affected on 2002 - 2003 models, and I wonder if Aston didn't know about this and quietly fixed it in-house on newer engine builds.
I'd be VERY interested as to what is involved to adjust the Oil Pressure at idle speeds.
That does have the ring of a letigious hysterical American about it...
So the car made a tapping noise, obviously not enough oil. I don't think you can 'adjust' oil pressure, probably just replaced the pump with a new or uprated unit?
Sounds to me like AM USA were lazy and saw $$ signs. Can hardly blame the factory;
'Hi my engine is tapping'
'What kind of tapping?'
'Oh you know, like a tapping sound' 'Right. Kind of hard to diagnose from here'
'What are you hiding? I want the truth!'
'YOU CAN'T HANDLE THE TRUTH!!'
Glad it got sorted cheaply and easily though, hope the oil starved engine has no problems long term either...
So the car made a tapping noise, obviously not enough oil. I don't think you can 'adjust' oil pressure, probably just replaced the pump with a new or uprated unit?
Sounds to me like AM USA were lazy and saw $$ signs. Can hardly blame the factory;
'Hi my engine is tapping'
'What kind of tapping?'
'Oh you know, like a tapping sound' 'Right. Kind of hard to diagnose from here'
'What are you hiding? I want the truth!'
'YOU CAN'T HANDLE THE TRUTH!!'
Glad it got sorted cheaply and easily though, hope the oil starved engine has no problems long term either...
If only it was this one isolated case....
As to date there are numerous V12's with the VERY same tapping noise.
It comes and goes and is not always evident.
Even BR listened to my own tap and were perplexed.
One guy has changed a lot of the head gear parts and still has the tap.
It's not a NASTY tap, just an annoying one.. and I imagine if there is a situation where pressure can "dip" (not drop totally), then I imagine lubrication would still remain just reduced enough to be a little more tappy.
Oil pressure can be adjusted but it's not a Sunday afternoon job. It means removal of the pump and then adding shims to the relief valve spring to alter the bypass pressure.
This will allow a higher pressure at idle but still allows the vales to operate at higher pressures, which simply dumps oil from the pump back to the sump.
Obviously if this valve sticks or operates too soon then oil is going right back to the sump and sending less to the engine.
It's only one of the theories behind this elusive but apparently common noise.
One guy right now is changing the cam chain tensioners as they think it is that!
Using an electronic scope cannot trace the source of the noise either.. very frustrating.
As to date there are numerous V12's with the VERY same tapping noise.
It comes and goes and is not always evident.
Even BR listened to my own tap and were perplexed.
One guy has changed a lot of the head gear parts and still has the tap.
It's not a NASTY tap, just an annoying one.. and I imagine if there is a situation where pressure can "dip" (not drop totally), then I imagine lubrication would still remain just reduced enough to be a little more tappy.
Oil pressure can be adjusted but it's not a Sunday afternoon job. It means removal of the pump and then adding shims to the relief valve spring to alter the bypass pressure.
This will allow a higher pressure at idle but still allows the vales to operate at higher pressures, which simply dumps oil from the pump back to the sump.
Obviously if this valve sticks or operates too soon then oil is going right back to the sump and sending less to the engine.
It's only one of the theories behind this elusive but apparently common noise.
One guy right now is changing the cam chain tensioners as they think it is that!
Using an electronic scope cannot trace the source of the noise either.. very frustrating.
Have been giving this more thought today and if it is Pump / Relief valve related then...
How about fitting an external oil pump to assist the original. Possibly source an electric oil pump that only runs when engine is running to save battery and this could be plumbed in directly from the side of the sump, an in-line filter could be used for more peace of mind and then dump the pressurised feed back into the rear tops of the head covers.
If you want to get even more creative you could run an extra oil cooler at the front and use steel lines to the engine tops and an in-line filter to each side.
I have heard of other V12's having engine problems with the rear cylinders so perhaps this would be a wise move and should be rather low cost to implement.
I think the rear oil drain plug is on the vertical back of the sump, so you could screw an attachment into here for the feed source, meaning no need to remove the sump at all for the modification.
If the original pump is fine then you have more oil fed to the rear of the heads = Good Thing!
If the original pump is lazy or fails then you have a back up pump working already = Good Thing!
As for the engines running a lot of heat,, adding an extra pump allows more cooling adaptations to be created = Good Thing!
You could easily fit a spray nozzle to the outlets inside the head covers so the new feed of oil is sprayed well over the rear 4 cylinder mechanics. Flow rate wouldn't need to be lots either a nice steady spray at low to med pressure would work so it would have no chance of lowering the sump level.
Anyway it's just an idea but a worthwhile mod that essentially has only gains and no real cons.
How about fitting an external oil pump to assist the original. Possibly source an electric oil pump that only runs when engine is running to save battery and this could be plumbed in directly from the side of the sump, an in-line filter could be used for more peace of mind and then dump the pressurised feed back into the rear tops of the head covers.
If you want to get even more creative you could run an extra oil cooler at the front and use steel lines to the engine tops and an in-line filter to each side.
I have heard of other V12's having engine problems with the rear cylinders so perhaps this would be a wise move and should be rather low cost to implement.
I think the rear oil drain plug is on the vertical back of the sump, so you could screw an attachment into here for the feed source, meaning no need to remove the sump at all for the modification.
If the original pump is fine then you have more oil fed to the rear of the heads = Good Thing!
If the original pump is lazy or fails then you have a back up pump working already = Good Thing!
As for the engines running a lot of heat,, adding an extra pump allows more cooling adaptations to be created = Good Thing!
You could easily fit a spray nozzle to the outlets inside the head covers so the new feed of oil is sprayed well over the rear 4 cylinder mechanics. Flow rate wouldn't need to be lots either a nice steady spray at low to med pressure would work so it would have no chance of lowering the sump level.
Anyway it's just an idea but a worthwhile mod that essentially has only gains and no real cons.
F1 NDW said:
I would think it unlikely that the oil pump pressure relief valve is
relieving pressure at tick over. Worn oil pump causing low oil pressure at tick over
possibly.
I agree with the above statement, to increase the pressure releif setting you would put a shim under the spring, maybe the fault was a worn or weak or even stuck releif spring.relieving pressure at tick over. Worn oil pump causing low oil pressure at tick over
possibly.
Certainly fits the Pressure Relief Valve, either sticking or the spring has weakened / Broken.
I drove mine today and took note of the Oil Pressure.
Idle = 3.5bar (a little I think)
In traffic cruising along = 4bar
A flick of the throttle gave a max reading of 4.5bar
Aston quote 4bar - 6bar for Oil Pressure, so the idle is .5bar under pressure on my engine.
Now when the problem is not occurring my engine is nice and quiet,, but following a heat up drive cycle, switch off for anything from 10 minutes or longer and the ticking begins.
Pressure Valve sticking.. certainly points to that sort of fault as when I turn the engine off the valve will attempt to move, if it sticks, then when next started the pressure will be lower than normal.
This is something I will monitor on EVERY start and restart cycle now and note when the noise is there and when not.
This may take a few weeks as I am not driving it every day now and I would like to keep the test as natural as possible.
I drove mine today and took note of the Oil Pressure.
Idle = 3.5bar (a little I think)
In traffic cruising along = 4bar
A flick of the throttle gave a max reading of 4.5bar
Aston quote 4bar - 6bar for Oil Pressure, so the idle is .5bar under pressure on my engine.
Now when the problem is not occurring my engine is nice and quiet,, but following a heat up drive cycle, switch off for anything from 10 minutes or longer and the ticking begins.
Pressure Valve sticking.. certainly points to that sort of fault as when I turn the engine off the valve will attempt to move, if it sticks, then when next started the pressure will be lower than normal.
This is something I will monitor on EVERY start and restart cycle now and note when the noise is there and when not.
This may take a few weeks as I am not driving it every day now and I would like to keep the test as natural as possible.
I already use Forte engine flush on my last oil and filter change. No real change!
It sounded quieter for a few days then came back as it usually does.
The ticking / tapping is approx half engine RPM, so would indicate valve train gear somewhere.
The problem with any intermittent fault is trying to source it 100%.
The tick, tap and occasionally knock come and goes of its own free will.
But there are instances where you can almost make it happen on cue.
(and now to be completely cynical)
Some companies probably design in weak points on a product to ensure further revenue down the line. ;-)
After all they'd never make any more money if products lasted forever.
It sounded quieter for a few days then came back as it usually does.
The ticking / tapping is approx half engine RPM, so would indicate valve train gear somewhere.
The problem with any intermittent fault is trying to source it 100%.
The tick, tap and occasionally knock come and goes of its own free will.
But there are instances where you can almost make it happen on cue.
(and now to be completely cynical)
Some companies probably design in weak points on a product to ensure further revenue down the line. ;-)
After all they'd never make any more money if products lasted forever.
Right, well an ideal Oil Pump is going to cost a few hundred quid.. so moving along.
You can buy much cheaper pumps circa £50 which are intended to Pre-Oil an engine prior to start!
Now this might be a way forward, if when turning the key and going through the start up procedure, one of these low cost pumps could wet all the top end nicely with oil before you press the button.
It might not resolve the ticking noise, or maybe it would, who knows.. but it's a nice idea to pre-oil the engine before every start and once fitted it would be an autonomous procedure.
You can buy much cheaper pumps circa £50 which are intended to Pre-Oil an engine prior to start!
Now this might be a way forward, if when turning the key and going through the start up procedure, one of these low cost pumps could wet all the top end nicely with oil before you press the button.
It might not resolve the ticking noise, or maybe it would, who knows.. but it's a nice idea to pre-oil the engine before every start and once fitted it would be an autonomous procedure.
I initially thought injectors myself, and have disconnected them all in turn when the noise was there.
No change at all.
But the only place you can get a reading with the electronic scope is off the fuel rails, noisy as heel as you might imagine.
I did once have the idea it might be a worn O-ring sucking air in and making odd noises, as any induction leak on either the inlet or exhaust side can manifest some strange sounding almost metallic like noises.
This was made more evident that by pushing on the injector rail we could make a very feitn sound that was VERY similar to the noise.
No change at all.
But the only place you can get a reading with the electronic scope is off the fuel rails, noisy as heel as you might imagine.
I did once have the idea it might be a worn O-ring sucking air in and making odd noises, as any induction leak on either the inlet or exhaust side can manifest some strange sounding almost metallic like noises.
This was made more evident that by pushing on the injector rail we could make a very feitn sound that was VERY similar to the noise.
Hello all! I see this post has been dead for some time now.. I'm hoping you all found solutions to your tapping problems. I have a similar problem as the last poster where the noise only comes from the fuel rail and until the car gets to full operating temperature the idle is absolutely perfect. Has anyone found a solution to this? Any suggestions? I had a bank 1 running lean code come out twice.. Any input would be greatly appreciated!
Edited by AMDB7V12 on Monday 4th August 19:39
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