Hi Guys,

I'm a new member here, not sure If I posted this in the right place. My XJ12 is making an unusual noise. Any guesses what it is or how to fix?

 

I presume it is the "whowing" noise, correct ?

Turn off the air con and check again. Normally an engine driven fan makes that sort of noise and its harmless.

 

Thank you for responding. No not that sound (Air conditioner was off). It's sort of like a ticking or "taka taka taka" sound.

 

My S3 V12 does not have the metallic ticking sound. You may want to try putting a stethoscope (or screwdriver to ear if you prefer ) and see if its coming from the valve covers or from one of the bearings/pulleys. If its tappets, it will usually be louder on startup when the oil pressure and viscosity is higher

You may also want to post this in the XJS forum, most of the S3 folks have the 6 cyl.

 

Fair dinkum, that is one ROUGH running V12.

That clicking is not easy to single out, but sounds a lot like very noisy injectors.

A valve seat loose or dropping is a LOT louder than that.

I would get some SERIOUS injector cleaner, and pour it in the fuel tank. I would use a heavy dose, such as one bottlle to about 20ltrs of fuel. Run it through, note if ANYTHING changes.

Removing said injectors for professional cleaning is a HUGE task. I have had success with these "injector cleaners" in all but 1 PreHE injector, which required a clout with a hammer to unstick it. Some people report NO success.

The fuel used is usually the cause of the injector issues, and Ethanol is usually more of a problem than good "old" petrol.

Loose spark plugs in a HE will give a very similar noise.

It sounds also like "tappet noise", which is a strange one in the V12, unless someone has been messing, but that engine looks unmolested.

As said, that rough running still heads me at the injectors just plain gummed up.

 

Gentlemen thank you for the advice, I will try out these recommendations and then let you know what happens. I purchased this vehicle recently so there are some growing pains at the moment. Grant Francis, here in Canada pretty much all fuels have 10% ethanol. I'm using Petro Canada Ultra 94 octane gasoline (contains 10% ethanol), but I will try switching to Shell V-Power 91 octane (only fuel sold here to my knowledge that has 0% ethanol). I will try the injector flush.

The Warlock, I will try the stethoscope (and make note that for future engine queries to post in XJS section). Thanks again, update to follow!

 

Looks like the cleaner did the trick. It's still ticking, but less than before. I'm going to keep treating the engine with every fill up, hopefully that'll make the noise subside entirely. Thanks again!

 

https://www.youtube.com/watch?v=l0hq...ature=youtu.be