Engine Noise - Any Guesses?

[Cunning Plan]

Okay so the old Cherokee at 149,000 has a little noise issue first thing in the morning, where on idle it sounds like a rattling chain-type-noise.

After a day at work, coming back in the evening it doesn't seem as noticeable and when the engine is warm, you cannot hear it at all.

I am assuming it is one of the belt-pullys with a worn bearing?

Any other suggestions?

[Incursus]

Ghost of Christmas past?    






or timing chain..

[Cunning Plan]

Quoting: Incursus

or timing chain..

There is no timing belt or chain on it as it is an OHV engine, so I know it isn't that.

Unless there is a small chain connecting the cam to the crank and it is driven by that instead of a direct drive.

[art b]

get a long screw driver or piece of wood,
 and place it on various parts of the engine,
 with ya earole on the other end and try to locate roughly where the noise is coming from..

[Roadkill]

Quoting: art b

get a long screw driver or piece of wood,
and place it on various parts of the engine,
with ya earole on the other end and try to locate roughly where the noise is coming from..

Quoting: Cunning Plan

Unless there is a small chain connecting the cam to the crank and it is driven by that instead of a direct drive.

I'd be shocked if there wasn't a chain in there . . .

[Cunning Plan]

Quoting: Incursus

or timing chain..

Quoting: Cunning Plan

Unless there is a small chain connecting the cam to the crank and it is driven by that instead of a direct drive.

Quoting: Roadkill

I'd be shocked if there wasn't a chain in there . . .

I've just checked the manual and there is:



I hope it is not that

Quoting: art b

with ya earole on the other end and try to locate roughly where the noise is coming from..

Roger that, I'll do it when I'm not rushing around for work and can take a proper look at it

[Cunning Plan]

Quoting: Cunning Plan

I've just checked the manual and there is:

Scratch that, that was the wrong engine. The XJ had two variants of the 2.5 litre engine, one was Petrol and the other was Diesel (my one). The image above is for the Petrol engine and I have just checked the correct Diesel version:



There is no timing chain!

So, that leaves one of the pulleys again

[Roadkill]

What an odd set-up.

Quoting: Cunning Plan

I'll do it when I'm not rushing around for work and can take a proper look at it

Then we'll go from there.

[Incursus]

Quoting: Incursus

Ghost of Christmas past?

 

[Andy]

Blaady hell, my gear hobber at work has a less intricate set up than that!

Yeah, you need to localise this a bit more and go from there. Do just make sure someone hasn't left anything loose in the bay though.

I had a really annoying intermittent vibration in my car in the bay. Ages and ages it took to find until one day I noticed that the engine cover was just touching the inlet manifold and at certain RPMs it would just be enough to tap away making a vibration noise.

[Incursus]

Are you sure it's from the engine bay? I had a loose bit of exhaust heat shield on the old Mondy that I first thought to be a nasty rattle from the engine..

It didn't seem to be protecting anything so I just tore it off.

[Cunning Plan]

Quoting: Andy

Blaady hell, my gear hobber at work has a less intricate set up than that!

Quoting: Andy

Yeah, you need to localise this a bit more and go from there

Quoting: Roadkill

Then we'll go from there.

Roger.

Quoting: Incursus

Are you sure it's from the engine bay? I had a loose bit of exhaust

There was a rattling from the first exhaust support mount / bracket that had corroded through. I took it off and it's on my 'buy-list' to get and fit a replacement. This is defiantly from the engine though

Quoting: Incursus

It didn't seem to be protecting anything so I just tore it off.

:redneck:  



I took a video first thing this morning so you can hear it too. It is more noticeable from the bottom of the engine when I move the camera down. It's almost a cross between a squeak and a rattling chain.

[Roadkill]

Going by the position you were when you could hear it most it definitely sounds like it's coming from the pulleys.

If it's rattling like that I'd *guess* that it's not a major load-bearing pulley (ie not the cam or crank) . . . My guess would be vacuum pump as it's a dry-running pulley.

The other likely candidate is the oil pump but that's below the oil line so would probably be leaking oil quite badly.

 . . . Or it could be none of the above.

I sometimes use a 3/4" piece of rubber hose to find engine rattles . . . like how Art said but being flexible you can get it "in" further . . . you'll need to press the end hard up against the engine, though, as all you'll hear otherwise is the air turbulence in the engine bay (Think stethoscope) - the other end tight over your ear.  It helps to block your other ear, too.

[Cunning Plan]

Quoting: Roadkill

I sometimes use a 3/4" piece of rubber hose to find engine rattles . . . like how Art said but being flexible you can get it "in" further . . . you'll need to press the end hard up against the engine, though, as all you'll hear otherwise is the air turbulence in the engine bay (Think stethoscope) - the other end tight over your ear. It helps to block your other ear, too.

Thanks buddy, but at the risk of sounding stupid, how do I do this with a spinning pulley?

[Roadkill]

Are all the pulleys open or is there a cover over them (I'd guessed a cover) ?

[Cunning Plan]

All auxiliary-drive pulleys are open, driven by one serpentine rubber belt as shown below:



(Ignore the question mark)

[Cunning Plan]

You can see the belt just on the alternator here, the image above is not quite the same engine:

[art b]

Quoting: Cunning Plan

Thanks buddy, but at the risk of sounding stupid, how do I do this with a spinning pulley?

fcuking carefully ...

[art b]

you should remove the ancillary/serp belt,
  to see if its anything external  driven by the belt, pumps,alt, fans etc..

[Cunning Plan]

Okay I made sure I had a look at this yesterday.

Quoting: art b

you should remove the ancillary/serp belt,

I went for this first and it totally confirmed that it is one of the pulleys driven by the drive / aux belt, because as soon as I took the belt off and ran the engine, it was the quietest it has ever been.



I put the belt back on and it seemed a 'bit' better, but I am not sure if that was because by that point it had warmed up and the noise is always quieter when it's warm. So, I went back out first thing this morning to start it again and the noise is still there.

Whilst doing some exploring around the engine, I did notice that the water pump is seeping a little bit, so I'll have to replace that, hopefully at the same time as replacing whatever is making this noise as I will have most of the front-end apart.

I have to say, it sounds like it is coming more from the fan pulley or the centre of the selection of pulley-wheels. Although, it's just too hard to tell exactly with all the noises of the engine. I did try putting a screw-driver against the non-rotating parts of pulleys I could get to, but it didn't really help. Another issue is I cannot put the belt back on to run certain components at a time to narrow the issue down because the belt runs literally everything, it's a beast of a belt. It's either all on, or all off.  

The fan is a thermal viscous fan and I am wondering if anyone knows if they usually have the noise issues mine has?



I think I will end up having to do this, take everything apart, except the fan pulley, then run the engine again, if there is no noise, then it must be the 'bimetallic' spring in the viscous fan.





I did find this in the manual, although the fan-blades seem fine, I couldn't spot anything loose.




I drove to Norfolk and back Friday / Saturday morning and it's fine (touch wood), but it's just annoyingly noisy first thing in the morning. Also, if it is the fan, rather than it breaking and the engine over-heating, I think I have to try and fix it.

[art b]

on my old audi the belt tensioner was worn,

 i took it of and lubed it then it was quieter,then fitted a new one,

its possibly one of the parts thet does not get changed...

[Cunning Plan]

Quoting: art b

on my old audi the belt tensioner was worn,

Yah, I remember your thread about it and that was a LOT of work (In fact, I even looked the thread up to find what your issue was before posting this thread).

I am going to call Central Auto's tomorrow to try and get a price for the tensioner. If it is not too bad, I might just replace it anyway along with the water pump O-ring seal / AND OR / water pump (dependant on cost).

As I say though, I am sure it is more from the centre of the engine than the left (as you look at the engine bay, which is where the tensioner is).

Annoying, when I have available 'tinkering' time, I want to be working on the bus instead  

[art b]

Quoting: Cunning Plan

Yah, I remember your thread about it and that was a LOT of work (In fact, I even looked the thread up to find what your issue was before posting this thread).

that was the waterpump driven by the cambelt....

it made a grinding  n scraping noise.. it was a well collapsed bearing ...

somehere in here ...

[Andy]

Vorsprung der ******* hell how does this go back together?!

To be honest apart from noticing the leaky water pump, if everything is working and nothing is losing/using fluids, just live with it? My old Mondy always sounded like shit first thing in the morning.

[Roadkill]

Quoting: Andy

My old Mondy always sounded like shit first thing in the morning.

My Mondey sounds like $hit all the time . . . always has done.  It baffles the guys in the MoT station each year when it rocks up with another 25-30,000 miles on it, still going strong and still sounding $hit !