Horrible rattling, any clues? VR6, PROBLEM FOUND, NOT

[mr_fusion 0]

THi All

 

Some of you have been following my progress with the rotrex charger and will now know i have decided to continue the project.

 

However, I now have a new problem that is driving me nuts.

 

So a little background info to start with.

 

New timing chains and tensioners New headgasket

New hydraulic lifters etc + all parts associated with this type or work.

 

(all parts about 3 months old)

 

 

Driving home last night from sainsburys, i clipped a couple of speed bumps on the heatshield under the cat. About a minute later there was a loud clattering noise from the engine.

 

I pulled over to look what was going on, but it was dark and wet so i drove slowly home (about 1/4 mile down the road)

 

So, today i decided to investigate further today and the horrible clattering noise is still there.

 

There is plenty of oil and the car has been running smoothly since the work.

 

I suspected a loose heatshield to begin with, so i jacked up the car to inspect but found nothing loose underneath.

 

Next I decided to check out the cams etc, so i removed the inlet manifold and rocker cover and inspected the cams, lifters and chains.

 

All look in excellent condition and there is no play in the cams and no sign of loose objects floting around in the oil.

 

So, i put the top of the engine back together and decided to remove the super charger and put it back to stock (charger, oil system, belt, pulleys, injectors etc).

 

Once back to stock, i started her up again, same noise.

 

The noise does not increases with revs, doesn't change when the clutch is pressed or if it is put into gear and move slowly forward.

 

The noise is a clattering / chattering noise a bit like some one has poured a pile of nuts and bolts into the inlet manifold and is shaking it about. The noise is pretty loud as well ( as you can hear from the attached file).

 

I have attached a recording of the noise (wav file) to give you an idea, but the quality isn't amazing as it was recorded on my phone.

 

NOW REMOVED TO AVOID CONFUSION - LOOK FURTHER DOWN THE PAGE FOR THE MP3. TA!

 

It gets quieter towards the end as I moved away from the engine bay.

 

Any ideas!!????

 

Cheers Guys

 

BenHi All

 

Some of you have been following my progress with the rotrex charger and will now know i have decided to continue the project.

 

However, I now have a new problem that is driving me nuts.

 

So a little background info to start with.

 

New timing chains and tensioners New headgasket

New hydraulic lifters etc + all parts associated with this type or work.

 

(all parts about 3 months old)

 

 

Driving home last night from sainsburys, i clipped a couple of speed bumps on the heatshield under the cat. About a minute later there was a loud clattering noise from the engine.

 

I pulled over to look what was going on, but it was dark and wet so i drove slowly home (about 1/4 mile down the road)

 

So, today i decided to investigate further today and the horrible clattering noise is still there.

 

There is plenty of oil and the car has been running smoothly since the work.

 

I suspected a loose heatshield to begin with, so i jacked up the car to inspect but found nothing loose underneath.

 

Next I decided to check out the cams etc, so i removed the inlet manifold and rocker cover and inspected the cams, lifters and chains.

 

All look in excellent condition and there is no play in the cams and no sign of loose objects floting around in the oil.

 

So, i put the top of the engine back together and decided to remove the super charger and put it back to stock (charger, oil system, belt, pulleys, injectors etc).

 

Once back to stock, i started her up again, same noise.

 

The noise does not increases with revs, doesn't change when the clutch is pressed or if it is put into gear and move slowly forward.

 

The noise is a clattering / chattering noise a bit like some one has poured a pile of nuts and bolts into the inlet manifold and is shaking it about. The noise is pretty loud as well ( as you can hear from the attached file).

 

I have attached a recording of the noise (wav file) to give you an idea, but the quality isn't amazing as it was recorded on my phone.

 

NOW REMOVED TO AVOID CONFUSION - LOOK FURTHER DOWN THE PAGE FOR THE MP3. TA!

 

It gets quieter towards the end as I moved away from the engine bay.

 

Any ideas!!????

 

Cheers Guys

 

Ben

[mr_fusion 0]

anyone?

[KADVR6 0]

i cant hear anything on my pc, is it just me?? or is the download not working.

[Jim 2]

It works alright.. problem is the recording device (I assume your mobile) sort of distorts the sound.. I really can't make out what on earth it is! :(

[mr_fusion 0]

I will try and get a better recording.. i wil post it up later

 

Cheers guys

[Lippy 0]

where abouts in the engine is it mate?

 

fair play for being able to that much to your engine too "check things out"!! glad your keeping the rotrex tho, didn't realise! will look up your old thread

[mr_fusion 0]

Right then.

 

Got the laptop out to get a better recording.

 

plugged it into vagcom while I was there.. no errors though.

 

See attached mp3.

 

p.s very hard to work out where the noise is coming from as its so loud. although seems to be top / behind the lump.

 

Could a loose heatshield really make this much racket though!!??

 

I'm pretty stumped as I can't locate the source...

[Jim 2]

That is dreadful! I really don't think it sounds like a heatshield, mostly because a heatshield is usually affected by revs, resonating at different RPM's, etc as well - as you say the noise does not get affected by revs so thats a bit confusing... :|

[mr_fusion 0]

I don't have any all pressure warnings (light or buzzer) but I am inclined to drop the sump and examine the bottom end to see if anything is amiss / loose down there.

 

I really hope its not bottom end problems as that may be prohibitively expensive to fix.

 

Any one else got any ideas to what it might be?

[rosswalker 0]

I'm guessing that you would have noticed this, but a few weeks back I went over a bump and had a horrible rattling similar to yours. I have a look around and it turned out to be the bonnet arm (bit that holds the bonnet up) the click had broken and the arm was out of place and rattling against the fan.

I dont have any idea other than that... fingers crossed for you.

[CorradoVR6-Turbo 0]

Are you running on all 6? Are your plugs showing any signs of oil,unburnt fuel ect..

 

I would pull the sump off failing that as heat shields dont make that kind of noise.

[mr_fusion 0]

Right then, i may have some new info..

 

I have been speaking to a friend of mine who has a 2L Audi A6 and apparently he hit his cat on a speed bump and shattered the innnards of it, as mentioned I hit a few speedbumps just before the noises started.

 

He says it made the same noise (except quieter) but this would probably be correct as the VR6 would probably be generating more noise in this area due to the bigger engine.

 

My decat pipe is on its way anyway (I ordered it last week) so I will find out when I fit it.

 

Any thoughts?

[CorradoVR6-Turbo 0]

There is now way on hell the cat on a VR will shatter,i dont know what they are made from but they dont brake(Ive tried this).

 

Old escorts yes..tap them wirth a hamer and hey presto...

[M15 VW 0]

sure its just not the heatshield? maybe it knocked the cat out of place.

[mr_fusion 0]

Well this theory has been confirmed as plausible by another source (VW specialists in shropshire) and they have seen it happen before (although whether specifically on a VR6 i don't know)

 

The cat is a ceramic honeycomb in 2 sections (as i am lead to believe) so it could happen with enough force?

 

The car had a side on accident before i puchased it (as it evident by the passenger side sill which is dented pretty deeply) so it may be 14years worth of knocks and its finally given way. +14years of hot engine gases and vibration from driving.

 

Correct me if i'm wrong, but aren't these things only meant to last 4-5 years anyway (80,000 km)?

 

At the end of the day, its one of the cheaper options I have as well as the fact that I have the decat pipe on the way. I will remove heatshields etc when I fit it so, time will tell.

 

refs:

 

http://www.carpages.co.uk/news/catalyti ... -09-05.asp

http://www.tecom.si/ang-page.htm

http://auto.howstuffworks.com/catalytic-converter2.htm

[dr_mat 0]

It's not unusual for cats to disintegrate. Usually it's thermal shock though, hot cat + cold water + minor thump = expensive accident.

[CorradoVR6-Turbo 0]

Just unbolt the Cat to find out,I've tried to de-cat a VR cat a while ago(159k M reg) It was unbreakable,its impacted but never shattered,I've tried this three times and never managed.

 

Cats resonate when loose at certain revs,not saying its not the cat,but the noise that's making .. No way,I've been a mechanic for 15 years and never heard that from a cat but I could be proved wrong.

Only way to find out is to take it apart.

 

Keep us posted.

 

James

[mr_fusion 0]

I still could possibly be items in that area (heatshields etc), but i was going to decat anyway because of the rotrex. It's just going to have to be a process of elimination...

 

Does anyone have any other ideas of what it may be though / experiences with similar (but maybe not as loud) noises?

 

p.s i am going to replace with a proper decat pipe, not smash out the innards of the existing cat to "decat" it :-).

[mr_fusion 0]

Right, i've had a chat with Vince and he is going to take a listen to the recording later at home, so maybe he will have a a better idea of whats going on!

[mr_fusion 0]

Ok, just been outside in the dark for another tinker..

 

Pulled all the plugs - 1,3,4,5,6 look ok - bit sooty

Plug 2 was a little wet with fuel, other wise they all look in good condition.

 

Had a peek down to the pistons, no obvious debris or loose parts in that area.

 

Only other thing i spotted was a small coolant leak from around the thermostat housing area, just a drip though.

 

I am starting to think that the noise is coming from the engine after all, just really hard to tell until i get get the C up on the ramps so I can have a proper look underneath.

 

Will see what Vince has to say when he gets back to me, either way I will have to wait until saturday before I can have a proper look.

[Goldie 2]

Only other thing i spotted was a small coolant leak from around the thermostat housing area, just a drip though.

 

Ive just been bitten on the arse with this, little drip after a while = big leak and car off road. Itll happen when you need your car aswell. Not an expensive fix so id recommend getting it sorted.

[mr_fusion 0]

Ok then,

 

Dropped the sump today. There was a definite dent in the bottom of it and a large scrape where it had hit the speedbumps.

 

There was no sign of debris in the oil, only slight light mettalic coloured oil that had settled at the bottom which I would assume is 140k of engine wear particles.

 

The bottom of the oil pump was dented (where the filter on the pickup pipe is) and this was conisistent with dent in the sump itself.

 

I couldn't see any obvious wear to the crank etc and the engine turned over fine with a 27mm socket on the crank with no clunking or tapping noises.

 

I have reshaped the pump back out with a heavy hammer, refitted and filled the oil back up again but the noise is still there. It does seem to be quieter and more specific now, but the same noise all the same.

 

Exhaust components all seem solid and the cat doesn't rattle when tapped. All the heatshields seem fine.

 

So still stumped.

 

I don't have any oil pressure warnings, but is it possible the oil pump is damaged internally and is making this noise?

 

It does increase speed with revs although I previously didn't think it did as i didn't want to turn the engine over to rapidly.

 

Anybody??

[CorradoVR6-Turbo 0]

With the damage to the sump and possibly blocking the oil pump you might have caused further damage internally.

Looks like you are out of luck and a strip is looking likely.

[mr_fusion 0]

Wouldn't bottom end oil starvation damage manifest itself in more of a heavier knocking noise though?

 

This is definitely a more tinnier rattle (like something small and hard knocking against thin metal) i.e a higher frequency sound than you would expect from the bottom end

[mr_fusion 0]

I also would have thought that at least the low oil pressure warning light would have come on if the pump was not working.

 

I am going to test the oil pressure in the morning anyway and swap to the decat pipe just to rule that out of the equation.

 

I understand that a bottom end rebuild is circa £2k which is not financially feasible in the circumstances (I only paid £1700 for the car originally)