Jaguar Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
61 Posts
Discussion Starter · #1 ·
Link to video

noticed a strange noise driving along parked cars with the windows down yesterday.

it only appears between 1000 and 1500rpm, not at idle.

Not heard very clearly with the bonnet up, more at the front wheels (lower part of the engine) video taken in P in the garage, very noticable.

I'm stumped.
 

·
Registered
Joined
·
5,996 Posts
Any clunk when you turn the engine off? If not I'd possibly be looking at timing chains, they were known for failing tensioners in earlier 5.0 engines, but the chain width was widened in later models.
 

·
Registered
Joined
·
61 Posts
Discussion Starter · #3 ·
That clunk wouldve been the blower coupler, which has been replaced for a solid one. I also dont think it the chains/tensioners because its quiet a warm restarts and idle.

I just did a cold start, the car holds the revs at 1200 for a while, where yesterday with a warm engine the rattle was most pronounced; dead quiet. So I'm warming it up now to see if its a warm engine only deal.
 

·
Registered
Joined
·
61 Posts
Discussion Starter · #4 ·
Seems to have shifted lower in the RPM range with a colder engine, around 1000-1200rpm. Went under de car to remove the bellypan and have a listen around with my stethoscope while wife tried to locate the rattle with the gaspedal but I cant find it.
 

·
Registered
Joined
·
4,747 Posts
If I knew nothing else I'd say that was timing chain slap. However that should be very evident and much louder with the bonnet up and emanating from the front of the engine, usually one side or the other depending on where the slap is occuring. My fuel pumps on the 3.0 SC make quite a pronounced and rattly/tickety noise in comparison to my 5.0 SC engine, they're on the left side of the engine, low down. But seems other forums have mentioned the 3.0 SC fuel pump noise as being normal. Strange the 5.0 SC doesn't have these reports though. These engines are not quiet though, the direct injectors themselves are noisy too.
 

·
Registered
Joined
·
61 Posts
Discussion Starter · #6 ·
Its a noisy engine, thats for sure. But this is a very pronounced tick/rattle. I checked the HPFP's with my stethoscope because I thought it was a suspect, but no.

The way it shifts RPM ranges with temp and is more pronounced on accel as opposed to decel makes me think maybe an exhaust leak somewhere at manifold/cat area.
 

·
Registered
2014 F-Type S V6 coupe most of the fruit and a few mods.
Joined
·
3,960 Posts
Its a noisy engine, thats for sure. But this is a very pronounced tick/rattle. I checked the HPFP's with my stethoscope because I thought it was a suspect, but no.

The way it shifts RPM ranges with temp and is more pronounced on accel as opposed to decel makes me think maybe an exhaust leak somewhere at manifold/cat area.
That's my thought as well, the first time I listened to the vid I thought it sounded much too deep and throbby to be any of the known AJ126 or AJ133 ticky or rattly noises.
Listening again just now it is a distinct throbbing resonance which sounds like an exhaust leak to me.
 

·
Registered
Joined
·
237 Posts
Just guessing....defective hydraulic valve lifter from Audi made such noise. I don't know the petrol engines from Jaguar. Or a defective clutch from the aircon compressor.
Does it sound more like an electrical issue (ignition spark) or like a mechanical issue?
Could you locate the origin better during your second video take?
I saw a video few weeks ago on youtube with a similar noise. It was a small Peugeot engine I think. Root cause was a defective plastic cover around the timing chain. Could have blocked the chain. Luckily it didn't.
Dirk
 

·
Registered
Joined
·
61 Posts
Discussion Starter · #12 ·
Great, even the local jag specialist couldnt pinpoint it with a stethoscope.

It's not the supercharger. Sound is coming from the back of the engine lower down.

Interestingly; I turned the AC off the have a better listen and we could barely hear it (in P). AC back on and sound is back, but it's not coming from the compressor. It also doesnt change the sound when driving, AC on or OFF, sound is still there. So it depends on the load on the engine.
 

·
Registered
🏴󠁧󠁢󠁳󠁣󠁴󠁿X260 R-Sport in Aurora Red
Joined
·
13,174 Posts
Fuels lines resonance?
 
  • Like
Reactions: FCS

·
Registered
2014 F-Type S V6 coupe most of the fruit and a few mods.
Joined
·
3,960 Posts
Great, even the local jag specialist couldnt pinpoint it with a stethoscope.

It's not the supercharger. Sound is coming from the back of the engine lower down.

Interestingly; I turned the AC off the have a better listen and we could barely hear it (in P). AC back on and sound is back, but it's not coming from the compressor. It also doesnt change the sound when driving, AC on or OFF, sound is still there. So it depends on the load on the engine.
"back of the engine lower down" combined with other symptoms points to the possible culprit being the secondary high pressure fuel pump.
Two HPFPs on the lower RHS of the engine block, one behind the other, and No 2 is towards the back of the block.
These HPFPs are known to go bad and rattle.
 

·
Registered
Joined
·
237 Posts
You said, you couldn't pinpoint it even from under the car. I had a rattling noise coming from the exhaust heat protection shield. One rivet was loose. I just wanted to let you know. You could only hear the rattling noise with windows open on the RH side. I believe your rattling noise is something different.

White Automotive tire Tire Motor vehicle Wheel


Dirk
 
1 - 16 of 16 Posts
Top