Hi! I've been lurking for some time but haven't posted much of anything. I own a 2014 V8S. I bought it with 7,400 miles on it and i'm now sitting at 29K and change. I love this car! I can't find anything online about changing the spark plugs on this V8 engine... the dealership is quoting $1000. I *did* have them replaced back in 2019 but it's been bothering me that I didn't try to do it myself. I generally do normal maintenance on my own. I would appreciate any advice you might have -- even if that advice is to let the experts do it.

Mark

 

nobody? i would appreciate some help.

 

I might be able to help you a little bit, but I have not changed these plugs myself. The layout is very simple and, if you have even moderate mechanical skills, this wouldn't be that difficult a job.

First, some details about this engine - It uses a similar platform to Mercedes AMG Hot V engine where I do have lots of hands on. This engine uses an "inverted" head design. The exhaust, essentially, is inside the "V" where the intake manifold is normally found, with the intakes, one either side, where on traditional v8s you would find the exhaust manifolds. None of this layout makes spark plug changes harder or easier...about the same.

I've circled the turbos (exhaust) in red, and one of the two intakes in blue. The 4 (of 8) coil packs in the bank shown are circled in green.

1. Remove the engine center cover
2. Remove both air filter boxes, This should expose the four coils on each side and at this point with the first two steps, engine should look like the pic.



The coils are held down by one torx screw each. They can be seen above in the green encircled coils.
3. Remove the torx screw, remove the coil (x 8). Unplug the harness on each coil.
4. Use compressed air with a blow gun tip and blow out the spark plug wells. They should be clean anyway, but just as a precaution.
5. Remove the spark plugs; replace new. A NOTE here, it is advisable to put a LIGHT (LIGHT!) coating of anti-seize on the spark plug threads ONLY. Some plug manufacturers like NGK already coat the threads with an anti-seize, but not all do.
6. Use spark plug grease on the tips of the coil ends that mate with the plugs. Use sparingly, don't get crazy loading the tips with grease.
7. Replace all the coils and the mounting screws being CAREFUL not to overtighten these. It is easy to crack the coil housing bearing down on these screws and they won't loosen on their own and don't have to be crazy tight.
8. Replace the intake filters; replace the center cover.

This is the simple process based on what I see here.

 

Thank you so very much for your response. I've changed the plugs on my Range Rover, my F150, and my sons 4Runner all in the last week. Your post gives me the confidence to tackle the Bentley. Thank you!

Mark