I hear sort of a pinging or metallic rattling from the V12 engine. It's most audible from below the car, on the driver side (this is a LHD SIII v12 sedan), and less audible from up top while looking at the engine bay. I've uploaded a few videos to youtube if any of you could listen and give an opinion. Unfortunately the noise is not quite as prominent in the videos. Not sure if I'm just paranoid, or if there's something to it. Thanks for any input.

From left side:

From right side:

Up top:

 

Quick history on the car: I've acquired the car from my brother, who has gone down the long path of restoring a BMW 2002. I want to confirm the health of the V12 before determining how much time and money to invest. He bought it 3 yrs ago and it ran and drove, but needed a fuel system overhaul among other work. He had both fuel tanks out and treated, new fuel pump, senders, changeover valve, fuel lines (in boot and to and from engine bay, not the injector hoses yet), etc.

It also needed new rear calipers and rotors as the brakes were iffy and a caliper was leaking, but that has not been done yet. He drove it some and got sidetracked by other projects. It's been started and driven a very short distance about once a month or every couple of months over the past 2 years. It's been stored inside luckily.

I started by checking fluids and added coolant. It seems to be losing some coolant but it's not ending up on the ground. I haven't done a proper bleeding procedure yet. I did a cooling system pressure test and coolant came out of the atmospheric tank overflow pipe which I guess is what should happen, right? I also did a block test to check for combustion gases in the coolant and it was negative. I did the test using the fill pipe on the crossover pipe. I'll probably do a compression test next, and if it checks out I'll go full monty on the cooling system and the IRS.

 

I can't hear anything in the videos, but the space is very tight under there, check that the exhaust isn't hitting anything. It's very close to the transmission.

Other thing it could be is the rear transmission mount. There is a foam piece in there that centers a locating pin and the foam breaks down over time. Item #3 in the drawing: https://www.jaguarclassicparts.com/u...ting-5-3-litre

If the bushing is gone, the rear of the transmission can move around and contact the mounting plate.

 

I had an issue that might have sounded similar - higher revs esp., the exhaust would tap a heat shield rapidly.
Just a suggestions.

 

Fair Dinkum, I wish mine were that quiet, especially the PreHE, damn.

Your market got the 11.5:1 comp ratios, the rest of us got the 12.5:1 rocket ships.

At idle they will NOT ping, not possible on a V12, it will fire on the precious cylinder before that happening, and burn your air filter elements.

I hear a SLIGHT noise, and thats with the Aids turned waaaaay up, and I reckon its exhaust gasket "ticking", as in the manifold to head, or the donuts near the transmission.

When yo gave it a few revs, its missing and farting a little, NORMAL for a neglected V12. They will SNAP to any revs in a blink when ya got it sorted as designed, and all the "fiddle stuff", unfiddled. It also sound "timing retarded", so maybe a seized distributor innards, VERY COMMON.

Fresh fuel, new fuel filter, nw plugs (gapped correctly), fresh oil, TPS setting checked (it sounds out a tad), throttle bodies cleaned, and thats the short list.

The V12 is STRONG, over heating is all that will really kill it, slack maintaing also shortens ANY engines life.

One of mine is nudging 700,000kms untouched.

 

defiantly sounds more like something rattling vrs something actually knocking or pinging inside the engine. could possibly be a exhaust gasket leaking as well.

 

Thanks very much for the input everyone. I'll press on with maintenance and will probably be back with questions along the way. Is 0.025 still the accepted spark plug gap for the 5.3L HE?

 

About the GAP!
Noah, you took the words right out O my mouth...

What say you, Mr Grant???
Edge O my seat here.

 

BEER, lots of BEER.

0.025 is the ONLY gap, repeat, ONLY gap for the 5.3 V12.

STANDARD spec plugs, NOTHING fancy, they dont like it, and the extra money could be used for BEER.

Maintain that sucker and DRIVE it, garages are not their place in the world.