Gentlemen, I am feeling a mild knocking while the car is at a stop light. It feels like its not idling correctly but I don't see the rpm gauge move at all. No engine codes come on to indicate a problem. The car drives great and no idle/knock while driving, only when stopped at a traffic light. Have any of you had this problem or have any recommendations on how to solve the problem?

Thanks in advance.
J

 

Do you know if it gets louder under load? For example if you have the handbrake on and try to gently pull away in first gear does the noise get heavier and a little louder? If so, that would probably point to something serious in the engine.........

That said, this is based on my experience with other engines. I've never really heard of such issues with the venerable DB9 V12.

FF

 

I have not tried that Frank, but wouldn't I notice some kind of problem while I'm accelerating hard? I've run the vehicle hard and fast in both manual and auto mode and it has no hesitation. I'll try your recommendation and let you know what happens. Thanks

 

Yeah, your probably right. I just thought it worth eliminating. Try it and let us know how you get on. In the meantime I'm sure some one who knows a lot more about these things than me will probably post a prognosis that is a lot more likely!

Something I tried once was taking a quick video and posting it on YouTube with a link here.....I got a lot of helpful diagnosis after that !

FF

 

You've confirmed the oil level is normal, right????

 

Id say check oil level and make sure the dipstick has been updated. I think on later years they changed the dipstick length but not sure exactly when or if there was a service bulletin issued I'm thinking most likely there was.

 

I had a ticking/squeaking sound at Idle in my V8Vantage--I would not call it a "knock". It was a Belt and Pulley problem that was corrected by changing them both.

 

I know nothing about the detailed mechanics of the V12, but based on my experiences with other cars, I'm thinking low oil pressure/low oil level at idle.

 

If you want to seriously scare yourself, have a look at this: http://www.astonmartinlife.com/forum...ise-t1162.html

Starts off about DB7 V12s but gets into later ones too.

 

I will recheck the oil level to see if that's the problem. I hadn't heard about a retrofit for the dip stick so I'll have to look into that as well. If it doesn't stop I'll shoot a video so you can listen to it. One final observation, it appears that it's coming from somewhere right behind where the radio, ac et.. controls are located. When I open the hood I don't hear anything.

 

It's not unusual to get rattles from the satnav unit. Check there too.

 

Checked the oil level and it was right at the max level. When I get a chance I'll drive it around and see if I can get a video of the problem.

Thanks

 

Hehe..not uncommon when a DB9 runs low on oil and starts taking corners. The engine requires 12L of oil. 6L stay in the sump for reserve and 6L flow through the system. I have seen some numerous clients bring there cars to corner shops and they don't fill up the oil to the level marks..I guess they didn't realize how much the cost of oil is..anyways they fill to around 9L..with services on Aston once every 12month, some clients try to reach the mileage count instead cause thats what the corner garage told them..nonetheless car engine runs low on oil and come in on a flat bed..I am averaging 1 engine per year to be replaced from another garages mistake..Becareful ladies and gents!!!

If you can get a recording of the noise and also describe what your doing to create the noise, describe what you do to delete the noise (raise RPM past 3K, get load on engine, get engine warm...etc)..that would be great!

I have seen damaged crank bearings, rod bearings,rods, wrist pins, lash adjusters...all were not normal wear though..cosworth did a pretty good job on making bullet block..concerned engines I seen either engine ran low on oil or hydro-locked from water..all client provoked(lack of servicing, running in deep water..etc)

 

Thanks Irish, the weather's been a little nasty down here (we actually got to the low 40's overnight) so as soon as it improves I'll drive it around and gather the data you suggested. Great idea!
Thanks,
J

 

"Nasty weather"..hehe, there calling for -15C(+5F) here by mid afternoon ..wanna trade?