Xj12 series 3 whining sound / vibration

(Ilkka Suppanen) #1

Hi
I have xj12 series 3 1991. About moth ago the engine started to “whine” between 1500 - 3000 rpm. Inside of car you can hear the strong"whine". Outside in engine compartment whining sound is bit damped because of all the other noises engine makes. There is also notable vibration outside of the car near engine.
Here is the link to the video from inside of the car, where you can hear the whine.
https://www.dropbox.com/s/st3gz6r6rb79fv2/xj12_whining.mp4?dl=0

  • The jaguar specialist changed all the engine mounts to new ones. Whine is still there.
  • He also all belts away and the sound/vibration was still there. Whine is still there.
    What this could be? We are baffled
    Sincerely, Ilkka
(David Jauch) #2

Hi Ilkka,
So you removed all belts and ran it; the noise still there. It is not load related but changes with engine speed regardless of what gear you are in, etc.?

If it is not the pulleys or ancillaries and not a vacuum leak, could the gearbox produce a sound like that? Other than that I have no idea what that could be, especially that loud, either. Maybe use a long rod or screwdriver to your head (beware of moving parts!) and narrow down the location as good as possible.

(Ilkka Suppanen) #3

Dear David
Sorry, I did not mention: The whining sound is there with gear(s) on, whiteout gear, and reverse.
Yes, The sound is there whiteout belts on.
You are right: We need to try to locate bit the the sound/resonance location with rod/screwdriver. So far we couldn’t really find the location.
We where wondering is it could be crankshaft damper? It is difficult to know whiteout changing it.
Thank you David.
Sincerely, Ilkka

(David Jauch) #4

I was thinking that the pump and torque converter (and some of the gearset, if I‘m not mistaken) run regardless of shifter position so there are parts in motion that could whine at engine speed.
The harmonic damper is just steel and rubber bonded together and I would not take it off. I do not know anything about V12s, so maybe there is a source inside the engine, but you might be able to determine whether the noise comes from the front or the rear of the engine.
Good luck.

David

(Ilkka Suppanen) #5

Thank you David

You are right, we should check pump and torque converter. Probably that is reason that we cannot find the source of whine in engine compartment. I have to to study it…

Sincerely, Ilkka

(Paul M. Novak) #6

Ilkka,
I don’t have an answer for your questions about that sound, however I recommend that you try posting to the Jag-Lovers V12 list as this appears to be more of a V12 engine issue than an XJ12 car related issue. Most posters on this list have XJ6s with a 4.2L XK engine and BW65 or BW66 transmission and you have a much different drive train with 5.3L V12 and GM400 transmission. I have two 5.3L V12/GM400 Jaguars but I have never heard that sound before.

Paul

(Ilkka Suppanen) #7

Thank you Paul for advice. I will do that.
Sincerely, ilkka

(Jochen Glöckner) #8

Ilkka,

no doubt, it is the warning buzzer for low fuel;-)

But seriously, just from the tone I seriously doubt it has to do with gears, valves, timing chain etc. And since it doesn’t correlate in pitch with revolutions I’d also exclude bearings and shafts.

My money would be on air resonances. Have you tried to take off the air filter? How is the fan driven? If it is a e-fan it’ll turn with the belts off, and if one blade has broken off an imbalance may both produce vibrations and fairly constant noise.

Good luck

Jochen

75 XJ6L 4.2 auto (UK spec)

(Ilkka Suppanen) #9

Dear Jochen
Air resonance is a good ques. I have to check air filters. There are 2 fans: One electric. They do not make this sound.

Sincerely, Ilkka

(Aristides Balanos) #10

Ilkka,

I agree with Jochen, I don’t think its either your transmission, either your engine, but rather some vacuum / air related noise.

Try disconnecting the Rochester valve and all hoses from the Vapor Recovery system and see.
Mine does the same noise but only for a couple of seconds at cold start up.

An other culprit could be any of the vacuum valves, the either crack, either the diaphragm gets hard and vibrates.

An other theory is the Radiator Air Purge system.
Is your engine full of coolant and have you followed the correct filing procedure ?

Keep us posted.
Aristides

(Ilkka Suppanen) #11

Hi

We found a cause and solved the sound / vibration problem!

The car mechanic Marco found that the source of sound was around oil filter and oil filter assembly.

By changing engine oil from 20W-50 to 20W-60 and changing the oil filter we solved the problem of sound and vibration. It was about 6000 km since the last oil change.

It is still bit unclear exactly what caused the whine: Was it: the oil filter, oil itself or the valve on the oil filter assembly? At least we know where to to look if whine returns.

Thank you all for profound and good help to narrow down the problem.

Sincerely, Ilkka

(Aristides Balanos) #12

That’s interesting Ilkka…
20W-60 though, is a thick oil, esspecially if you live up North…
I would recomend on the next change to go back to 20W-50.

Best,
Aristides

(Frank Andersen) #13

**
Indeed, Ilkka…

The change of oil should have no effect in itself - I would suspect the ‘fiddle factor’; working in the area touched and rectified something sensitive?

Theoretically; as oil is flowing through, noise may be generated due to restrictions, loose bits or air - as noticed with power steering.

The filter may have been the culprit in this case - for some obscure reason.

While 20/60 is not necessarily harmful; it may cause excessive oil pressure - so I think changing back to the 20/50 or lower is pertinent…

Frank
xj6 85 Sov Europe (UK/NZ)
**