cliffcoggin

Sorry Loquex. As usual with recordings made on a phone there is too much extraneous noise to hear whatever you are referring to.

Hello Gareth. I've not had that problem so no direct experience. Assuming the sensors are clean, I suggest looking for water ingress or a damaged wire. I daresay you have probably already thought of that so apologies if I am teaching grandma how to suck eggs.

Most pads have an adhesive that is softened by heat, so try a hair dryer, but not a paint stripping heat gun which is too hot.

That's unfortunate.

Timing chains rely on a tensioner to prevent the chain jumping a sprocket tooth so I expect yours is worn out, however as the tensioner pad slowly wears it usually leads to a lot of noise which is the warning I mentioned earlier. Did you have any such noise before the chain failed? I believe the tensioners on Audi engines are hydraulic so there may be a problem with its oil supply in addition to wear of the pad that bears on the chain.

Your mechanic has rightly assumed the valve stems will be bent and will have to be renewed. He has also estimated for flattening the head which may no longer be flat enough to seal against the block. Flattening ( or levelling in your words) involves setting the head on a large milling machine and cutting as much metal off as is necessary to achieve a dead flat surface, usually in the region of 10 to 20 thousandths of an inch. It's a problem more often associated with an over heating engine. I don't know the details of your engine but it must have a belt, a chain, or gears to drive the camshaft. Gears have been out of favour for decades, and chains are rare nowadays, so I assume it has a belt. Check your service schedule in the handbook to find out exactly what should have been done and when. Your service history will show if the scheduled work has been done.

The video doesn't really help. I suppose a split in the turbo intake connection would explain the noise and the oil leak, but I would have expected your mechanic to have seen any such split. I have never worked on a turbo so can not suggest anything further.

James. Thanks for detailed description. It is rare for such a full explanation to be provided for us to work with. I don't believe the price you have been given is unreasonable for the work your mechanic has suggested. The damage to the pistons seems minor and you can probably get away without changing them. If you are really lucky the head will not have been bent and the job will be cheaper, but you won't know until the head is off. What you need to be aware of is the possibility of damage to the conrods. It's only a small possibility if the failure occurred at cranking speed; if it had happened while the engine was running the chances of conrod damage would be far greater and might require a complete engine rebuild. This is a classic example of the damage that happens when timing belts are not renewed in time. Belts, unlike chains, give little warning of imminent failure, hence the need to renew them according to the manufacturer's schedule. Do please let us know the outcome.

Daryl. I never heard my turbo make any sort of noise, so given that you can hear yours and there is an oil leak in its vicinity I'd say yours definitely needs to be taken off for investigation.

118000 miles would be fine providing the car has been looked after, however high emissions and a lack of service history make me suspicious. You may be lucky that a service will solve the problems, but somehow I doubt it, though I would be happy to be proved wrong.

If the vibration was not present before the garage worked on your car, take it back. The mechanic may have forgotten something as simple as an engine mount not being fitted correctly for example.

The same question gets the same response: send a photo with dimensions. How is anybody here supposed to know what it looks like without a little information?

That's very good news Joshua. It almost restores my faith in car dealers.

Audi perhaps?

Is this the same problem you wrote about on 7th September? If so, what did you do about the Mechatronic control?

Only now do you tell us that it is a long standing problem that has had no influence on the MOT test. A pity you did not mention it earlier. Is there any other relevent information you have been withholding? Has it been inspected at a garage? Both Gareth and I have suggested rear tyres yet you have not mentioned them in your replies.

And no vibration at the steering wheel or pedals? In that case I would look to the rear tyres being damaged or out of balance as the most likely candidate. That does not rule out other possibilities such as worn wheel bearings, loose wheel nuts, warped brake discs but they wou;d cause symptoms that you have not mentioned.

John. Good idea to only fix what's broken because renewing parts at random could cost you as much as a new car. With so little information to go on there are dozens of possibilities, so let's try to get some specifics. [1] Can you feel any vibration when the noise starts, and if so where? (Floor, steering wheel, pedals.) [2] Does the noise change when you fully open and fully close the throttle at 60 mph? [3] Have the road wheels been balanced recently? [4] Does the noise change as you turn the steering wheel? (I appreciate you can't go full lock at 60 mph so don't turn further than is safe.) [5] Has the car been serviced according to the schedule, particularly regarding engine belts, water pump, etc?

You would do better to ask the seller if it will fit. If he will not guarantee it will, buy elsewhere.

Guess that puts him on my "Ignore" list, along with a few others who regularly pose questions and fail to inform us of the outcomes. That's their loss, not mine.

I have seen no updates yet. What did your mechanic say Asif?

I agree with Gareth that incipient corrosion should have been detected long before it became so bad that structural failure occurred. That is precisely what the MOT test is for, so somebody is concealing something. A substantial piece of steel like that can not go from being acceptably fit for purpose in May to a complete failure in just five months. As for the cause, I have never known this sort of failure on any car of any age so I wonder about corrosion or mistreatment. I see you are nowhere near the sea but salt treatment of the roads for de-icing in winter is a possible source of corrosion, particularly if you do not occasionally wash the underside of the car. Mechanical mistreatment might involve jacking the car wrongly or at the wrong point thus weakening the steel. Both possibilities seem remote, but I can not think of another explanation. I believe you can be confident that there is no inherent defect in the original Audi components, so the failure must involve the way it has been used or treated.

Does the engine speed also go up and down, or is it just the tachometer reading that changes while the engine speed is constant? Is this the same jalopy you asked about in June and failed to inform us of the outcome?

If he did find a solution he kept it secret from all of us, rather than sharing it with others in a similar position. It's an all too familiar, and typically discourteous, response from those seeking help here.

In that case I'd agree it's worn linkage.