Help please with a new noise from my V8 SC motor (AJ133),. I had the remedial coolant pipe replacement job done the other week by a local indie (supercharger out) and I'm now noticing a kind of low frequency rumbling / whirring noise from the engine at idle. It seems to be coming from the top left hand side of the engine but hard to pinpoint. Grateful if anyone has any ideas what it might be. I'm starting to worry! Please see video file and audio file attached. I had to convert from MP4 so the picture quality is poor, but the audio is okay. I've also attached a standalone audio file in case the video won't play on some devices. Many thanks

 

My 2019 V8 makes that exact same noise in the same location. Mine is under warranty, so I took it to the dealer and they did the "couldn't reproduce" nonsense.

So I bought OEM pulleys and tensioners for that side of the engine, and I am about to replace maybe as early as tomorrow, if I have time. I am pretty confident it's one of the pulley bearings. I am hoping it's not the AC compressor, but the noise seems to be higher up than the compressor. My car only has 26K miles, which is low for a pulley bearing failure, so I hope this solves it. There are a lot of pulleys on these engines.

 

Agreed, very likely a pulley bearing, just need to identify which one.
Maybe a mechanic's stethoscope will help or at a pinch the old school stethoscope, a long handled screwdriver with the blunt end held to your ear.

 

Some of these pulleys are hidden, so it could be hard to listen to them. I am doing what you're not supposed to do by throwing the "parts cannon" at the problem and just replacing all of them on that side.

 

Thanks guys. That's really useful info. (For a while, I was worried it might be something really bad like they didn't put the right amount of supercharger oil back in - but I guess that would make a more 'mechanical' noise?).

@lotusespritse please let me know how you get on with changing the pulleys. I'd would be good to know how it goes. ("parts cannon" made me smile - it is the kind of thing I would do!)

 

Please do not ever do this "old school stethoscope" trick, a real mechanics stethoscope can be ordered for $25 and can save you a lot of "headaches" from the blunt force trauma to the skull.

 

I didn't get to it today due to family things. But I will find a way to do it this week, even if I have to spread it over a couple of days. It shouldn't be too much work. One of the pulleys is buried behind the thermostat housing, so hopefully I don't need to open up the cooling system. I am changing the 2 pulleys (mine has electric power steering, so they replaced the power steering pump with a small pulley) and 1 tensioner pulley for the accessory belt. I am not going to do the pulleys associated with the supercharger belt at this time.

 

Thanks for the update. Be super interested to know which pulley was causing your noise. It is possible mine might be the same one (and give me an idea of what to check first).

 

I will post what I find. My money in on the tensioner pulley.

 

Ok, no joy.

First, the new tensioner I bought from Virginia Beach Jaguar was the wrong one. It was the right part number on the box for my car's VIN, but it looked very different and absolutely could not be mounted to the car. I don't know where the mistake happened. They are sending another one that does match what mine looks like and it was in the same box with the same part number. When I google the part number, some look like my old one and some look like the one they sent me, so I can't fault this dealer's part's department or their website. Mine says Jaguar Land Rover, and the one they sent me says FoMoCo.

When I removed my tensioner, it seemed perfectly fine. I did not feel or hear any noises in the pulley, or when moving the tensioner with a large 1/2" wrench. So it is probably ok and not the problem.

I did replace the 2 pulleys that I bought that matched up fine. The good news is that there is enough clearance to remove the pulley from behind the thermostat housing, and you can even get an extension between the hoses to properly torque the pulley bolt.

I was not liking the amount of play in the water pump pulley when I wiggled it, but it's not leaking or making any noise when I spin it.

After it was all put back together with the 2 new pulleys, there was no change in the noise. As usual, the parts cannon approach was not a good one, but it eliminated a couple of the pulleys. I may proactively replace the water pump due to the play, and who knows maybe it's making the noise. It's very hard to pinpoint where the noise is coming from with the rest of the engine running.

Maybe I need to run the car without the belts on to be sure it's a belt driven accessory causing the issue. Has anyone run the car without the accessory belt just for a short time for testing, and if so, did it cause the car to freak out? I know people do it all the time with the supercharger belt.

 

@lotusespritse sorry to hear you didn't get it sorted on the first dive in. Mine is booked into the garage for 11 April (the earliest they can do) so will report back and let you know what they find with mine. I had the water pump changed only a week or so ago, so unless it is a defective (new genuine JLR) water pump, if the noise is the same it might not be water pump related. Hope this helps. I sent the garage a clip of the sound and they also said it sounded 'pulley' related.

 

My rumbling noise became intermittent. Sometimes it would do it, sometimes not, so I feared a 'no fault found' diagnosis. Fortunately, a trusted indie with a good reputation in the UK diagnosed it to be the supercharger pulley assembly. It is the part shown below. The main (larger) bearing was wobbly, but it only comes as a complete part with the 2 other pulleys attached. They also changed the supercharger belt at the same time for good measure.



It seems to have fixed it so far, but will wait and see how it goes!

 

What happened? did you try running the engine without the belts?

 

Bearings of idler pulleys & tensioners commonly can be the culprit with rough engine noises and should be the first things checked.
Luckily they're probably some of the easiest & cheapest failures to replace, but if they're not tended to & replaced when they start to fail it will cascade into a bigger bill when it completely fails & destroys the belt while being driven.

 

I haven't done anything since my last post. I did received the correct replacement tensioner from the parts department, but I haven't installed it.

The noise is intermittent for me too, and lately, it's been very quiet. I am probably going to change the rest of the pulleys and the tensioner when I do a bigger service that includes cooling system maintenance. I didn't like the play in the water pump pulley, so I will change it at the same time.

 

Hope you get it sorted okay. Hopefully when you change the other pulleys the noise will vanish.