Hi

I am in process of replacing my 2009 DB9 spark plug, ignition coils.
When I removed the spark plug I notice little bit of dark glue like oil in 2 of back most spark plug wells on both sides.

I was wondering if it's possible to DYI AND REPLACE FOLLOWING MY SELF
VALVEL COVER GASKETS 07-85057 and 07-85056
Front crankshaft oil seal 03--85067
Rear crank shaft oil seal - 1R12-01-10434
Sliver rear seal 4g43-01-10194
Gasket, sparking plug hole

I was thinking since I am in the area where these things are why not replace all the seals and gaskets?

Is this a risky job? Any thing I need to know, special tools and techniques?
Has anyone done this kind of stuff?

Thanks in advance.

 

I'm following this one. How many miles on your '09? It make sense to replace the seals and if it was a Porsche 928 with 100K, I'd say go for it. I don't know this 5.9L yet to say. Hopefully Old phart will chime in here. Take some pictures along the way please.


Regards

 

Valve cover and spark plug are simple DIY; others are definitely not unless you want to remove the motor.

 

I would say the valve cover gasket, along with whatever gasket seals the spark plug opening. The rest I would leave alone as long as they are not leaking

 

For valve cover gasket service manual says remove rear suspension to get access to 2 bots holding some electric harness.

I am confused by that how does remove rear suspension help in front of the car ? Is it necessary to do this step.

Another thought floating in my head is what if I wait till leak is more profound, right now there was only little oil in well and around spark plug almost like 2 ml or so. It did not even soil the ignition coil, only base of the spark plug

 

30000 miles on DB9

 

Did my plugs and coils at 30K. Had some oil in the intake which I was told not to worry about. Didn't have anything on the plugs so I didn't mess with the valve covers. Was tempted just to see the top end of the engine. Though with the way things are packed under there I'm guessing the back of the covers will be a b**ch to get to.

Please take pics if you decide to tackle it.

 

When trying to get the valve covers off, you'll notice there's a plastic bracket looped behind both heads and secure to the back most lower cam cover stud(the plastic composite is not flexible). The bracket also bolts to the bellhousing/torque tube. So they tell you in the WSM to lower the rear suspension for access and removal of this bracket. If you don't get the bracket off the cam cover, the cam cover is not going to come out....

With oil in the plug holes, that's going to force a misfire and depending on how long the oil has been in there, you'd also have to replace the coils. Now everytime I've ever replaced 1 coil, others on that bank start to get flagged for a misfire. So when ever 1 coil gets replaced, it's always recommended to replace the whole lot. That's unless you don't mind opening it up to replace each coil flagged over and over again..just the V12 at that time didn't have knock sensing so the misfire is being flagged by rotational speed indifference, which doesn't always flag the correct cylinder unless an actual KOER test is being done and the misfire is present at that time tested.

 

Thx Irish for valuable update.
Should I dare to replace can cover gaskets and spark plug well gaskets by myself, I have done reasonable amount of work on my Bmw, db9 and Lamborghini but no means I am pro.

Is there any other secrets or tricks I need to know? Anything I must avoid?

Do you have any pictures of the plastic bracke thing you are talking about or point me to parts diagram?

If I remove rear suspension, is it possible to put back everything I my garage? I do have lift.

Thanks.

 

Well this just got real interesting.

 

Well..I've attracted a "big brother" watching everything I do on social sites. Publicly I have to say, I don't know of any tricks except the workshop manual procedure "**insert emoji**", but if you take a few minutes and look at the bracket over the stud, I'm sure you can figure something out.


What I can say to help out is, you might also want to replace the bolt/grommets that hold down the cam cover, their one of the reasons the cam cover will continue to leak. Not that they've been changed/revised, but trying to torque them down again can cause them to snap,...especially if you don't know how many times they've been removed/refitted in the past and are now too far stretched. Also pick up a tube of Loctite 5900 and paste some on the 4 tri-joints (cam cover/timing cover/head all meet).

 

Ok, I am confused, how can oil in the SP tube cause the coils to go bad?

Coil is sealed, so I cannot see how this would happen, can you please expound on this?

 

I'm no electrician, so I'm sure someone can jump in on this..but here's my theory on "why" is causes a misfire. It's not that it's "possible", it actually does cause a misfire, that's been proven to me on more than a hand full of V12's.


The plug grounds with the cylinder head, which ground and completes the entire ignition circuit. If you fill the spark plug tube with oil/water..any liquid that is conductive, the electric charge from the windings can ark the liquid and by-pass the plug to ground. Electricity will always travel the easiest and fasted route first and drain off excess on any other circuit due to its resistance. So oil/liquid gets the majority of the coil charge and the spark plug gets enough to trigger a small spark that's useless labelling a misfire due to the slower rotation at commanded spark period.


The coil seals the top of the tube from water and any other deposits from entering, but if the cam cover seal over the spark plug tubes are faulty and leaking oil..oil will leak into the tubes. Once enough oil is in the tube, misfires are present under load.


The coil does seal over the plug, but the rubber of the C.O.P is not oil resistant, so the motor oil swells the C.O.P rubber and allows the oil to be ark'd by the coil charge

 

I also had some oil in a few plug wells, I changed the cam covers as it seemed logical not to leave oil in an undue location.You can remove the harness bracket without touching the rear suspention,you just need to be persuasive and it will go, not a big job.

 

Love that photo!