Total Engine Failure (what would you do/advise guys/gals)

I'm interested to see whats found too.
Mine is currently at stealth with compression missing from number 2 cylinder.
I'm going to have the head rebuilt anyway but Vince has noticed the head gasket was starting to delaminate with soot being evident in the laminatations - if that makes sense.
The little diesel has now got 207k miles so some time at the "spa" is long over due.

Good luck with yours
Jonathan
 
Hi All,

Right, it's good news, but in the context of an expensive repair. The lads a The Volvo Workshop, who are OUTSTANDING, report that the bottom end of the engine is fine.
"What did they find" I hear you say? Well, turbo failure caused (not sure how, I guess the bits of metal?) a valve to become bent, and damage it's seat - that's it!
They have quoted, including a brand new turbo and engine flush out that includes the head £2k all in...an expense I could do without but for the work they've done that's a good price in my book?

The dilemma I face now, and I really need your collective help on this one, do I fit a brand new turbo and keep the car (now at 84k, I'm worried about Duel mass flywheel, gearbox etc) or fit a good (2yr guaranteed) recon turbo and trade the car in.

Thing is, prior to the turbo issue, we had just serviced it and she was fine (apart from my wife putting petrol in it...£300 for the drain and new filters)

Do you think I should book it in for a check at the main dealers, do you think they'd know if the gearbox and DMF are sound?
 
The valve damage would most likely have been caused by oil getting into the cylinder head when the turbo failed. Oil (or any liquid) doesn't compress, so something had to give!

RAB
 
Rab, that's interesting, I visualised shards of turbo fins flying into the pots, so how does the oil get in without being burned?

More results/steps in the right direction.

Gave Audi Sheffield a call, asked them if they'd have a drive of the motor to provide an opinion (not guarantee) as to the state of the DMF and gearbox; £50 for 1/2 hour...not bad, that's all I got.
So, with a bit of searching I found what appears to be one of the only long-standing top end car dealerships in Sheffield and even though they weren't going to make a penny out of me (well, not yet) the couldn't have been more friendly and helpful ; putting me onto a specialist that in their words 'these are the only guys we'd consider' in the area. So, gave them a call and again experienced more helpfulness. The technician who I spoke with provided me with heaps of advice on how to check for things, what to listen out for and so on. Furthermore, he said that he'd be happy to look and test drive my car free of charge. And, if he thought it warranted further investigating, would provide a diagnostic service "to establish the actual root cause" if anything did feel out of line so to speak.....£46.

The variations within the motor trade are quite simply unquantifiable.
 
RAB said:
The valve damage would most likely have been caused by oil getting into the cylinder head when the turbo failed. Oil (or any liquid) doesn't compress, so something had to give!

RAB
Click to expand...

It cant be the oil that damaged the valves.
If they are firmly shut, then they cannot be bent no matter how much oil is in the cylinder, only the stems will bend and the valves have to be open for them to bend.
If they are open then there is no compression.

I am rarely confident of anything, but I am confident that oil in the cylinders WILL NOT bend valves.

It could grenade an engine, but not bend valves.

Steve B
 
When a turbo fails, the seals that stop the oil that's pumped through the turbo escaping into the exhaust and the engine inlet, also fail. Result: oil floods into the engine intake - the engine is still running. If the quantity of oil in the cylinder is greater than the volume of the combustion chamber, what do you think happens when the piston reaches the top of it's stroke, given that you cannot compress oil? The engine will then hydrolock, the cambelt could slip, putting out the timing. That's a more likely scenario than the tiny little turbine breaking up (they don't usually) and bits getting through a long length of oil-soaked tubing, with a 'U-bend'.

RAB
 
RAB said:
When a turbo fails, the seals that stop the oil that's pumped through the turbo escaping into the exhaust and the engine inlet, also fail. Result: oil floods into the engine intake - the engine is still running. If the quantity of oil in the cylinder is greater than the volume of the combustion chamber, what do you think happens when the piston reaches the top of it's stroke, given that you cannot compress oil? The engine will then hydrolock, the cambelt could slip, putting out the timing. That's a more likely scenario than the tiny little turbine breaking up (they don't usually) and bits getting through a long length of oil-soaked tubing, with a 'U-bend'.

RAB
Click to expand...

Hi Rab,

I can absolutely agree with that scenario, the abrupt stop of the crankshaft and the momentum in the valve timing continuing to turn and slipping teeth would certainly cause the bent valves.

Thanks for that
Steve B
 
I would have expected a total lockup ought to be evidenced by a damaged / snapped cambelt. Can't remember whether OP mentioned it or not.
 
No info, I think. Remember, for the alternative hypothesis, any debris would have to negotiate the intercooler as well as the oil-soaked pipework. Would the bits be large enough to bend a valve? Also the turbo shaft has a weak point so that the shaft snaps if it touches the casing, rather than disintegrating. I know - it happening to me, courtesy of my (ex) MOT garage!

RAB
 
I agree with the logic that even if the alloy turbo compressor wheel broke, bits would unlikely get through the intercooler system and back into the cylinders.
Debris does not however need to be very large as small pieces can wedge a valve open so the piston finishes it off.
Other things to consider, with hydraulic lock there is a more than even chance that a conrod would be bent.
Any significant oil leakage from turbo shaft seals tends to get in all cylinders, fuelling the engine and causing it to 'run on' out of control.

Realistically we don't have enough info to do any form of failure analysis but its fun trying.

Cheers Spike
 
Hi,

It certainly is fun trying!!!!

I can see the logic that it is quite a journey for any fragments (through the intercooler etc) but surely the same applies to the oil??
In fact even with a huge flow of oil, it surely wouldn't get anything other than a smidgen into the cylinders, if at all? and the oil feed to the turbos is not huge, so surely the amount that would get past would be reasonably small???
Whereas tiny bits of metal (they would have to be tiny to get through the vanes of the intercooler) might just make it, and as Spike has said, it just takes a small piece!

So I have an open mind on this, but surely an inspection can show what happened, if it was oil then the cylinders would still have a fair bit in them as well as the manifold and intercooler. If it was due to bits of metal then they too would show up and the piston head and/or valve seats would show signs.

So I would be interested to know what can be told from a strip down.

Steve B
 
Birchall said:
I can see the logic that it is quite a journey for any fragments (through the intercooler etc) but surely the same applies to the oil??
In fact even with a huge flow of oil, it surely wouldn't get anything other than a smidgen into the cylinders, if at all? and the oil feed to the turbos is not huge, so surely the amount that would get past would be reasonably small???
Whereas tiny bits of metal (they would have to be tiny to get through the vanes of the intercooler) might just make it, and as Spike has said, it just takes a small piece!
Click to expand...
Why is it more likely that bits of metal will reach the cylinder than oil, when oil weighs less and would not be stopped by the intercooler? Just remember, there will be no positive pressure, just the suction of the engine at this point. My Lupo lost 1L of oil into the exhaust and the intake, in no time at all!

RAB
 
spike said:
I agree with the logic that even if the alloy turbo compressor wheel broke, bits would unlikely get through the intercooler system and back into the cylinders.
Debris does not however need to be very large as small pieces can wedge a valve open so the piston finishes it off.
Other things to consider, with hydraulic lock there is a more than even chance that a conrod would be bent.
Any significant oil leakage from turbo shaft seals tends to get in all cylinders, fuelling the engine and causing it to 'run on' out of control.

Realistically we don't have enough info to do any form of failure analysis but its fun trying.

Cheers Spike
Click to expand...

Spike,

Get off the fence! LOL.

Surely any oil is more likely to get into the cylinders nearest to the EGR/intake?

RAB
 
RAB said:
Why is it more likely that bits of metal will reach the cylinder than oil, when oil weighs less and would not be stopped by the intercooler? Just remember, there will be no positive pressure, just the suction of the engine at this point. My Lupo lost 1L of oil into the exhaust and the intake, in no time at all!

RAB
Click to expand...

Because oil is a fluid and sticky, whereas bits of metal not much bigger than dust are dry and light and tiny and so could be sucked in. That was what I was thinking.

Hold you hand full of tiny bits of metal close to a vacuum cleaner hose and see what happens, now try with a pool of oil in your hands, the hose would have to get VERY close to the oil before it would be sucked up, VERY close!!!!

Steve B
 
Birchall said:
Because oil is a fluid and sticky, whereas bits of metal not much bigger than dust are dry and light and tiny and so could be sucked in. That was what I was thinking.

Hold you hand full of tiny bits of metal close to a vacuum cleaner hose and see what happens, now try with a pool of oil in your hands, the hose would have to get VERY close to the oil before it would be sucked up, VERY close!!!!


Steve B
Click to expand...

Bits of metal not much bigger than dust won't cause a valve to collide with a piston! So if oil won't be sucked up, won't the metal bits be held by the oil? It's not either/or, it's both oil and maybe metal. Actually the tiny nut on the end of my turbine shaft came off. Do you know how far it travelled? About an inch! Maybe two, if I'm generous!

If you need proof that oil can reach the intake, take the pipe from the intercooler outlet off at the engine end and see if there's any oil. There will be, even with a new turbo!

RAB
 
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RAB said:
Bits of metal not much bigger than dust won't cause a valve to collide with a piston! So if oil won't be sucked up, won't the metal bits be held by the oil? It's not either/or, it's both oil and maybe metal. Actually the tiny nut on the end of my turbine shaft came off. Do you know how far it travelled? About an inch! Maybe two, if I'm generous!

If you need proof that oil can reach the intake, take the pipe from the intercooler outlet off at the engine end and see if there's any oil. There will be, even with a new turbo!

RAB
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Hi RAB,

Good debate this!!!

With so little clearance between the valves and the piston crown, it would only take a small piece of metal.

I have never doubted that oil can get into the intercooler, but with a considerable height from the bottom of the matrix to the top and then to the inlet manifold, it would be quite a journey for a sticky liquid. Also for a small piece of metal too.#

Whatever it was it is not much of a surprise, the stems on the inlet valves are as thin as nails and so bend easily.

I am certainly not saying you are wrong, all I am saying is that I am not yet convinced that it was oil OR metal shards, both would have quite a journey!

So a strip down should show the cause, the rest is just theory.

Thanks for keeping this as a friendly debate.

Steve B
 
Hi Steve, Rab and all.

I hope to visit the lads working on the car tomorrow. I'll do my best to identify what actually caused the damage. Just a thought as were debating oil and metal or both, surely the main protagonist in this story is the piston head? I have no idea of what clearance exists inside an modern engine, only ever stripped down motorbike engines (we're talking 1980's), could a loss in timing cause a valve to meet said piston. Thinking about this, there would be more damage to the other cylinder surely, if cam-belt timing were the cause.

I'll get back once I spoken with the professionals.
 
Richardu said:
Hi Steve, Rab and all.

I hope to visit the lads working on the car tomorrow. I'll do my best to identify what actually caused the damage. Just a thought as were debating oil and metal or both, surely the main protagonist in this story is the piston head? I have no idea of what clearance exists inside an modern engine, only ever stripped down motorbike engines (we're talking 1980's), could a loss in timing cause a valve to meet said piston. Thinking about this, there would be more damage to the other cylinder surely, if cam-belt timing were the cause.

I'll get back once I spoken with the professionals.
Click to expand...

There is only a tiny amount if clearance between valves and piston.
The most common cause of bent valves is cam timing.
Whether he timing slip caused the problem or was caused by the problem we will only know with a strip down.
So my money would be on a timing slip.
Since metal and oil have such a long journey to the cylinders.

God luck

Steve B
 
Birchall said:
I have never doubted that oil can get into the intercooler, but with a considerable height from the bottom of the matrix to the top and then to the inlet manifold, it would be quite a journey for a sticky liquid. Also for a small piece of metal too.#

Whatever it was it is not much of a surprise, the stems on the inlet valves are as thin as nails and so bend easily.

I am certainly not saying you are wrong, all I am saying is that I am not yet convinced that it was oil OR metal shards, both would have quite a journey!
Click to expand...

Inlet valve stems are certainly not as thin as nails! They are case hardened as well (usually harder than the guide) and certainly don't bend easily!

Have you heard of diesels that self-destruct due to running on oil rather than diesel? The only way you can stop them is by stalling. That happens when the turbo fails.

RAB
 
RAB said:
Inlet valve stems are certainly not as thin as nails! They are case hardened as well (usually harder than the guide) and certainly don't bend easily!

Have you heard of diesels that self-destruct due to running on oil rather than diesel? The only way you can stop them is by stalling. That happens when the turbo fails.

RAB
Click to expand...

Hi RAB, you are certainly right about the valves, I was in "petrol mode", the inlet valves on the 1.4 ARE thin as nails, I forgot for a moment that this was a diesel related thread (age related memory loss).

But you can't have the oil thing both ways, one minute you are saying that the oil would stop the engine dead and now you are talking about it NOT stopping it at all, in fact the opposite.

I know how that particular problem works, the engine simply burns the oil as if it was poor grade diesel and so switching off the key only shuts off the fuel supply, the oil still runs from the oil feed.

But that was my point, the quantity of oil from a broken turbo is not huge (the oil pipe is quite narrow I believe) so it would probably burn it.
To get enough into the cylinder to cause a fluid lock the intercooler would have to be full and a blown turbo is not going to run on long, the drop off in power and the noise means that the engine is normally stopped quite quickly.

As I have said, I hope you are taking this as a friendly debate, I am just enjoying the discussion, nobody can be proved right or wrong unless the strip down shows anything.

We cool?

Steve B
 
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