Engine rattles

[Roger Blassberg 0]

There's a rattle from the engine when I start it from cold. I can't work out where it's coming from.

 

It's worse at low revs, and disappears above about 2000 rpm. I never take the revs above 2500 until the oil gets above 70 deg. It is more pronounced if the aircon is running. Once the engine is warm it goes away altogether at any engine speed.

 

Oil pressure (cold) seems good; if I start the engine from cold, the oil pressure warning light has gone out before the engine has caught. Switch off immediately then back to position 2, and the light takes at least 10 secs to reappear.

 

The rattle is regular and similar to a big end. The head/cams and bearings/followers/springs/etc all are less than 10K miles, but the rest is 171K. I've no evidence that the cam drive chains/tensioners have ever been changed.

 

I am a bit confused as, if it were a big end , I would expect it to be more pronounced when the engine is hot and the oil pressure is lower. Also, it goes away at 2000-ish when cold, or at lower speed on a progressively lighter throttle. Needless to say, I drive VERY lightly until it warms up.

 

Oil is Magnatec, changed very regularly.

 

I haven't yet taken out plugs 1 and 6 to see if there is any ovalisation, leading to possible piston slap - what does piston slap sound like ??

 

I recognise that diagnosis is difficult from afar, but perhaps I'm not the first one to have had this problem, and I would welcome any help or suggestions.

Best wishes

 

RB

[Henny 0]

Porsche stopped using Magnatec as they found it was causing odd oil pressure problems in their engines... worth bearing in mind... ;)

[dinkus 10]

It could well be your timing chains/tensioner as they rattle the most when cold and around the 1k-1.25k revs. The best description I've heard is that they sound like marbles rattling in a can. If you want something to to compare, there is a sound clip of a dying set of timing chains somewhere on the vwvortex.com forum. I'll dig it out and post it here when I get home if you want.

[PhatVR6 0]

don't run it again!

 

my 2.8 did that, and I foolishly ignored it thinking it was worn tappets....

 

the cam chain tensioner has probably lost it's lining. it had on mine.

 

it' needs a chain job. if you continute to run it you'll risk the chain jumping a few teeth and bending valves.

 

at 171K the chain system and it's tensioners are guaranteed to be f8cked, even if they were changed at 90K.

[Kevin Bacon 5]

It's piston slap.

 

My 95K one does it.

 

Tom's 45K one does it.

 

Worry ye not. Most of them do it and Vince has already reassured me about it time and time again. It's not the big ends or camshaft rattle, but purely the pistons being cold. My rattled goes after about 20-30 seconds. How about yours?

 

K

 

EDIT: Or during the time it took me type this, it could also be the chains! Mine have been done as has the head and Vince checked my bores and gave me the thumbs up, so it can only be pissy slappers.

[Henny 0]

Humm... :roll:

 

I think it's probably best if you get someone to have a look at it Roger, as I think we've just proved that we can't diagnose it without actually seeing/hearing it in person... ;) :|

 

It could be something normal, and nothing to worry about, or it could be something expensive which needs doing PDQ, but without someone who knows these things actually getting their hands on it, you were spot on when you said "I recognise that diagnosis is difficult from afar" :lol:

[Kevin Bacon 5]

It's going to be chain related or piston slap, so that's only 2 suggestions so far...... :roll:

[dinkus 10]

So does it sound like this? (the shaking of a tin of marbles noise is the one you have to worry about!)

 

Edit: Grr it won't let me upload the wma file, it says it's not allowed as an extension.

 

Then when I click "Allowed extensions and sizes" I get a load an error message.

 

OK, change of plan, I've put the sound file HERE

[Kevin Bacon 5]

Nice one dinkus.....a noise paints a 1000 words :lol:

[dinkus 10]

Nice one dinkus.....a noise paints a 1000 words :lol:

 

Similarly 'crunch' costs a thousand pounds? Or something...

[Kevin Bacon 5]

Or £2550 in your case :mrgreen:

 

That was low....sorry! The tree is still flat on it's side, poor thing!

 

If the chains let go or skip a tooth, then yeah, couple of thou to put right :cry:

[dinkus 10]

Or £2550 in your case :mrgreen:

 

That was low....sorry! The tree is still flat on it's side, poor thing!

 

It's ok that was what I was referring too. I made the call to elephant today and found out my excess is actually £500 not £400 as I thought :roll: but it means it should bring the actual cost to them down to £2k and that included the extra bits too. So with any luck it won't be a write off, even with their rediculous valuation.

 

And yes, it may be expensive to get the chains done, but you'll have a nice quiet engine and a new clutch afterwards. It's a damn site better than having a valve plough into a piston when the chain jumps a tooth too.

[Kevin Bacon 5]

And just to expand on the last paragraph, Stealth's Head, chain and clutch package gives you a lovely engine, providing the block isn't past it. It basically restores the engine to more or less how it was when new and you realise then what you've been missing out on :lol: Especially in the midrange and low speed pull/smoothness.

[Jim 2]

Wow... that chain rattle is a terrible noise. The VR6 death rattle! :(

 

Though the quality of the recording is excellent.. hehe.

[dinkus 10]

Wow... that chain rattle is a terrible noise. The VR6 death rattle! :(

 

Though the quality of the recording is excellent.. hehe.

 

Yeah that's the kinda sound you don't miss easily... luckily :)

 

And yeah I'm dead impressed with the quality, but I can't take credit, it's the one that was on vwvortex.

[kvwloon 0]

Now that would be a damn fine idea....a database of common engine noises to watch out for and what they are.... :idea:

[dinkus 10]

Now that would be a damn fine idea....a database of common engine to watch out for and what they are.... :idea:

 

It needs to be added to the buying guide really.

 

I'll put it into the how-to website when I have the strength.

[Roger Blassberg 0]

good grief !! :shock: no, it sounds nothing like that. It's a very regular rhythmic rattle, as I said similar to a big end clattering away. It disappears when the engine gets up to 60 deg and only at low-ish revs..

 

OK, thanks all, and good night. The thing to do is to get the old girl to a proper doctor. Referals to good experts in Herts/Beds are gratefully received; if not I will make The Pilgrimage to the famous "Vince at Stealth", who seems to know what's what. Who knows, he might be able to cure the pinking as well!!

 

Best wishes

 

RB

[Roger Blassberg 0]

Finally on this, I have now booked an appointment with Vince at Stealth, in late August, so let's hope that nothing goes bang in the meantime !!

 

Thanks again for all your diagnoses.

 

Best wishes

 

RB