Cylinder head damage

Started by hartster, November 21, 2007, 05:06:24 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

hartster

Car is a 1993 100 quattro V6, AAH code.

A while back it started missing on cold starts. Miss would go away after 20-30 seconds.

Then started noticeably using coolant. Miss at cold start got worse. Then started blowing steam out the pipes. When left for a couple of days, #2 cylinder plug would become wet with coolant. So I parked it up and thought 'blown head gasket' and left it for 3 months.

This engine is known for head gasket oil leaks, not coolant leaks. The oil leak problem was so bad the original OEM gasket was upgraded in 1994 (?) - but mine has the original gasket part number.

Took it apart today. Removed heads - no noticeable problem with gaskets at all, on either side. But the #2 head is badly pitted, with corresponding damage to the piston, see photo.

What could cause this damage? never seen this kind of thing before.

I'm thinking the head or block is cracked?

I'm fed up fixing this car, even though it's been a good drive for 4 years it's now 250,000km, can't be arsed anymore. I'll go as far as new head gaskets and head skims but if it needs any more than that then it'll be in the bin... Unless of course there's a mint low mileage AAH motor lying around somewhere  ;D


[attachment deleted by admin]

John Stone

Wow, never seen that before, was it running lean?

John
86 WR
04 A3
05 V50T5

hartster

#2
Quote from: John Stone on November 21, 2007, 06:21:24 PM
Wow, never seen that before, was it running lean?

No I don't think so.

The head is cracked. I took the photo immediately after spraying solvent on it to take the coke off, and didn't look at it after that. It's actually bloody obvious - bottom right of photo. I've also cleaned the gasket with solvent and you can see where the coolant was flowing.

I'm gonna run a feeler gauge around the bore - maybe there's a broken ring that's caused the piston / head damage.

qta4

#3
corrosion in the head has caused problems with the V6, incorrect or ineffective coolant anti-corrosion effect.

Also looks like valve guides badly worn on that inlet valve, could cause oil into combustion chamber, result low level detonation.......maybe

Also looks like head gasket may have been leaking (close to sparkplug)
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

hartster

The head gasket has been leaking around near the plug. Now that's it's all clean it's very obvious. I haven't put a straight edge on the head yet to see if it's warped but I'd say it's probable.

The damage to the head really looks like something has been smashed around inside the combustion chamber.


hartster

Quote from: qta4 on November 21, 2007, 06:49:18 PM
Also looks like valve guides badly worn on that inlet valve, could cause oil into combustion chamber, result low level detonation.......maybe

The valve is open, the angle of the photo doesn't show that very well.

hartster

And now the lad has just puked about 250ml of fermented milk all over the back seat of the Subaru.

And of course a while back the cat pissed all over the carpet of the 16v. I need new carpet.

Cars suck, I'm gonna become Armish and get me a mule.

qta4

I have seen detonation damage that looks like engine has digested something before, but you would have a better view.
Photographs can be misleading
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

qta4

Quote from: hartster on November 21, 2007, 07:05:18 PM
And now the lad has just puked about 250ml of fermented milk all over the back seat of the Subaru.

And of course a while back the cat pissed all over the carpet of the 16v. I need new carpet.

Cars suck, I'm gonna become Armish and get me a mule.

Us old guys have been there done that, just part of the experience of being a parent, incidents like this are what creates memories that you will be able to recall at 21'st birthday parties.


Years ago, we were going to a plunket progressive dinner, we were asked to bring a flagon of cherry for the one of the hosts, on the way had to brake hard to avoid a dog, flagon lauched off the back seat on to the floor and shattered against the seat subframe of our brand new commodore.

Sold car in the end, stink was huge, should have claimed insurance
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

hartster

I've not had problems with detonation before, and to be honest I don't notice any problems with this car - it drove really well. What can cause detonation damage in one cylinder only?

hartster

Quote from: qta4 on November 21, 2007, 07:16:12 PM
Us old guys have been there done that, just part of the experience of being a parent, incidents like this are what creates memories that you will be able to recall at 21'st birthday parties.


Years ago, we were going to a plunket progressive dinner, we were asked to bring a flagon of cherry for the one of the hosts, on the way had to brake hard to avoid a dog, flagon lauched off the back seat on to the floor and shattered against the seat subframe of our brand new commodore.

Sold car in the end, stink was huge, should have claimed insurance

I once had a carton of milk leak all over the rear of my old man's company car while he was away overseas. It flowed down into the air con ducts under the driver's seat. It smelt so bad that I did a deal with the Fleet Manager who organised a replacement (he was an old family friend). When the old man got home he went ballistic wanting to know what had happened and he just wouldn't accept that he had a new car just cos the old one 'smelt bad'. Anyway new one was a Carlton 3.0 24v, the old one was piece of crap Rover Vitesse that was going to fall apart anyway.

qta4

Makes your cylinder problems fade in significance eh ;D
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

BB

 Maybe the seeping water and coolant was at a level where it kind of got carbonized in the combustion and caused that damage ???
The end is nigh, but the end of what is the question?

hartster

This is the second 100 / A6 we've had in the family, all the other Audis have been A4 / A3. Great to drive, great cruiser, economical, safe, blah blah blah. The first A6 was the wife's dads car and that was fine, but he bought it quite new.

But this one has had crapE reliability at high kms. The state of the internals on this motor translates to 'sell for parts'.

What's really pissing me off is the new brakes I fitted just before the misfire started.

I touted the idea of an engine recon but the wife made it quite clear that as far as she is concerned its Subaru Outback or Subaru Outback.

John Stone

Quote from: hartster on November 21, 2007, 08:34:26 PM
I touted the idea of an engine recon but the wife made it quite clear that as far as she is concerned its Subaru Outback or Subaru Outback.
How cruel......

John
86 WR
04 A3
05 V50T5

Angle

Quote from: hartster on November 21, 2007, 07:05:18 PM
And now the lad has just puked about 250ml of fermented milk all over the back seat of the Subaru.

And of course a while back the cat pissed all over the carpet of the 16v. I need new carpet.

Cars suck, I'm gonna become Armish and get me a mule.

It was worth checking on VASK late at night just to read this  :D

BB

Cruel? I think its would be far more cruel to try and fix that old heap and foist it on her to drive still, they are unreliable at that age no two ways about it. A subaru outback is a very very good car, do it she is a smart woman and knows what she wants but also puts up with you and your old vags so how can you go wrong ;)
The end is nigh, but the end of what is the question?

hartster

Quote from: hartster on November 21, 2007, 08:34:26 PM
I touted the idea of an engine recon but the wife made it quite clear that as far as she is concerned its Subaru Outback or Subaru Outback.

Yeah well options are limited for us, we need AWD and we need a wagon next time round. So its Subaru or VAG Passat / A6 wagon AWD.

The idea of a Hiace 4WD diesel was mentioned by a neighbour   :o

Looking at trademe there's a lot more low mileage Subaru options, pricing is pretty keen compared to VAG too.

hartster

Quote from: BB on November 22, 2007, 07:48:49 AM
Cruel? I think its would be far more cruel to try and fix that old heap and foist it on her to drive still, they are unreliable at that age no two ways about it. A subaru outback is a very very good car, do it she is a smart woman and knows what she wants but also puts up with you and your old vags so how can you go wrong ;)

The wife reckons BB is a very wise man  ;D

It's a pretty foregone conclusion...

BB

I wish my partner was as kind to me :(
The end is nigh, but the end of what is the question?