Hi,

My X308 (3.2, 2001, LH drive) recently started to make a very weird noise during the first 20 seconds or so after I start the car on a cold morning.
It's not every time I start the car though, like 30% of the time.
It sounds like slapping a leather belt on the side of the car door.
The car idles fine right after startup (when the noise is present).

I don't know if this helps, but my coolant lines popped off after a long drive (I used very cheap hose clamps...), but it never overheated, because it happened right after I parked the car.

You'll hear the noise around 6-10 times in 20 seconds, so its not very fast, but it is very loud.
I think the sound is coming from the left-front of the engine compartment near the ABS pump. No leaks there or ABS warnings though.

I tried searching on ABS pump noises, but that is mainly the grinding or jet-engine noises. Mine sounds like a very loud knock.

Does anyone know what this could be or what I can do to check for any possible ABS pump issues?

Thanks in advance!

PS:
I will try to record the sound tomorrow morning (if that helps) and I will upload it here.
I will also try to turn off the air conditioning pump, to see if that is the culprit.

It sounds exactly like this:

You Tube

 

That’s a new one to me. If it were mine, I would remove the drive belt right after I got home for the evening and when I start it the next morning see if the noise changed.

How many miles/kilometers does it have? Have you done anything with the chains, guides and tensioners?

 

Good one, I will remove the belt when I get home and try again tomorrow. I asked the person on that YouTube video (X350 I think) what his/her issue was and said that the water pump needed changing. I replaced mine 6 months ago, so that couldn't be it, right?

All the chains and guides have been replaced with aluminium ones. The car has 230.000 km / 143.000 miles.

The belt is also 6 months old, but it was soaked in coolant for a day because of my issue with the cheap hose clamps. Some people report squeaking/slipping belts after they did not clean the coolant off of it. I have another belt lying around somewhere, so that would be my next step if the noise is gone after starting without the belt tomorrow.

 

Well I have to admit that is a new sound for me as well. If it was a rod knock it would be a lot more songs in succession instead of this low frequency knock every second or so. I have no idea what the sound is from but I’m curious to find out

 

My 2000 XJ was making the exact same noise. Not always, only on cold start, and primarily in cold weather. In my case it was the (new) tensioner pulley sticking then releasing. For some reason it would oscillate when cold. New Dayco belt, new Litens tensioner assembly, no apparent reason to do that. I replaced the tensioner under warranty and it hasn't happened since.

 

Thank you for the response. I will see if I have a spare tensioner to swap (bought a complete engine / transmission a while back for spare parts, haha)

 

lol. I bought a complete although partially disassembled jaguar S type for parts just in case

 

I have had this happen, usually after a long rest or starting up on a cold morning. It was the belt, which seems to develop a “memory” from the tensioner pulley, which causes the tensioner to slap every time that spot rolled around. Replacing the belt with a Contitech fixed it. Good quality and has no memory effect.

 

I think you are right. I will order a decent quality belt instead of a new tensioner since a new tensioner costs around £ 120 / € 132 where I live.

I removed the belt this weekend and started it up, no weird sounds. After reinstalling the belt, and starting it the next day there was no noise either. It was not (that) cold though.

UPDATE:

I've ordered a Contitech belt, so in around 2 weeks it should be here.

 

So yesterday I replaced my cheap belt with a Contitech one and now the noise is gone. Consider this fixed. Thanks