Not sure about a wet test, I've always done it dry. Here's a good YouTube on a compression and leak test. It's really important that you have a good quality set of gauges and not some cheap POC from China -

Catastrophic Piston Failure 2.0t TSI Engine ~ Walkthrough and Diagnosis

 

Have you already tested dry?

If the reading is off you try wet - this can help tell you if the piston rings are the issue.

5ml seems a little BUT when you think about it the rings would normally be pushed up against the cylinder walls to create (mostly) a seal which allows for air and fuel to compress. It is only a few mm between piston rig end gaps and those are staggered to help create a better seal and less blow by. Once the rings are worn too much this seal against cylinder walls can be compromised and "loose" - when doing a wet test this is the space the oil takes - you don't need much due to tight tolerances in an engine.

 

Not sure about a wet test, I've always done it dry. Here's a good YouTube on a compression and leak test. It's really important that you have a good quality set of gauges and not some cheap POC from China -

Catastrophic Piston Failure 2.0t TSI Engine ~ Walkthrough and Diagnosis

Yeah bought a Laser gauge for 60 quid, prob nowhere near the most expense gauge but should be ok for all that I'll use it for. Yeah those Chinese things look like toys ffs.

 

Have you already tested dry?

If the reading is off you try wet - this can help tell you if the piston rings are the issue.

5ml seems a little BUT when you think about it the rings would normally be pushed up against the cylinder walls to create (mostly) a seal which allows for air and fuel to compress. It is only a few mm between piston rig end gaps and those are staggered to help create a better seal and less blow by. Once the rings are worn too much this seal against cylinder walls can be compromised and "loose" - when doing a wet test this is the space the oil takes - you don't need much due to tight tolerances in an engine.

Yeah it was dry tested whilst getting the ECU checked (garage beside the auto spark) but then the lockdown kicked in and mechanics closed up. The paranoia is getting to me and at least I'll know if it's a piston by checking it wet.

It was 12 12 12 09 dry praying it's a valve or spring, or it's most likely toast if piston work is on the cards [smiley=bomb.gif]

 

K. So definitely compression is down on 4.

Best thing to do now is a leak down test. This can help you find where the issue is (rings, valves or head)

What bad/strange incident happened prior to you bringing it in for compression checks?

 

It had a misfire on cyl4 which eased from very rocky on cold idle to barely noticable at full operating temp. Seems to me metal is expanding somewhere to fill a gap. No classic head gasket symptoms like mixing oil/coolant.car drives perfectly otherwise.

 

Well, I've just done it and cyl 4 went from 162.5ish dry to 177.5ish wet

All other cylinders are 180 - 182.5ish dry

Is that enough of a jump to indicate ring failures, or should there have been a big difference? Bear in mind that it's a BWA which are know for oil consumption due to rings, so possibly within scope??

 

I'd say replace the engine or service the rings.

You're already noticing a significant performance drop. The pressures should be within each other's figures. #4 is an outlier. The engine no likey and it's showing up as errors. So. Yes. Something is "wrong enough" that you're noticing it and the computers are picking it up too.

It'll only get worse. (Sorry to be the bearer of bad news but ... I'm not going to lie)

 

I'd say replace the engine or service the rings.

You're already noticing a significant performance drop. The pressures should be within each other's figures. #4 is an outlier. The engine no likey and it's showing up as errors. So. Yes. Something is "wrong enough" that you're noticing it and the computers are picking it up too.

It'll only get worse. (Sorry to be the bearer of bad news but ... I'm not going to lie)

I'm guessing replacing rings is going to be crazy money, even at an independent garage?

 

Well it's a ton of work ...

Then it depends what they find is the cause that might increase the bill more. Might be a good consideration to get a bore scope (small insertable camera) to have a look inside #4 to see if there's damaged to the block.

Good luck.

 

There was no sign of oil on the spark plug and no smoke out the exhaust and car still pulls like a train, it's a sickener

 

After a quick look around engines are 1500-2000, I think a rebuild might be the option as the car is immaculate in and out (only saving grace for it atm), I'd be loathe to stick an unknown quantity engine in and find out it's as bad. Only issue with rebuilding is who's doing it! Rep of Ireland has no car scene at all hence no specialists, may have to take it up home to NI. Had only just spent 500 on a new timing belt kit before the lock down as well as 600 on tyres [smiley=bigcry.gif]

 

Sorry to hear about your issue and hope you get it resolved. If it is cactus you should be able to buy a reconditioned motor with some kind of warranty. As a matter of interest what is your mileage and what has been your oil consumption prior to you noticing the problem at idle.

 

72000 miles
Uses around 1tr over 700-800 miles

Not a lot of daylight between engines and rebuilds as far as I can see tbh, unknown quantities 1500-2000, I'd rather have it rebuilt and know it's a 100% strong engine. I wish this damn lock down was done with so I can get a mechanic to verify it's def rings. Seems cyl4 is a popular cyl to go down, as opposed to the other 3, there are so many posts on cyl4 probs over forums. Has to be a common link???

Can't believe I've been caught with a lemon, dealer will be speaking to my solicitor asap!

 

72000 miles
Uses around 1tr over 700-800 miles

Not a lot of daylight between engines and rebuilds as far as I can see tbh, unknown quantities 1500-2000, I'd rather have it rebuilt and know it's a 100% strong engine. I wish this damn lock down was done with so I can get a mechanic to verify it's def rings. Seems cyl4 is a popular cyl to go down, as opposed to the other 3, there are so many posts on cyl4 probs over forums. Has to be a common link???

Can't believe I've been caught with a lemon, dealer will be speaking to my solicitor asap!

I know it is a long shot but that kind of oil consumption may have passed audis engine replacement test. See attached and I know of one recently being replaced on this forum in the UK but obviously depends on all the circumstances. There is nothing to lose by you taking the car in for an oil consumption test at an Audi dealer. If they pick up the low compression on cyclinder 4 you could argue that is the fault of their sub standard pistons which is the reason for the high oil consumption.

 

These are the threads from the person who had theirs replaced by audi recently
https://www.ttforum.co.uk/forum/viewtopic.php?f=19&t=1932769
https://www.ttforum.co.uk/forum/viewtopic.php?f=19&t=1943371

 

Cheers, yeah saw a few cases of Audi contributing towards repairs. The car just had a dealer stamp 'history' with no proper receipts, in fact I have amassed more of a proper history in my ownership. Wouldn't Audi demand a full SH from their main dealers?

I flagged it with the trader I bought it from and the warranty company as it expired 2wks after lockdown, warranty company said they stand over any possible claim when I get it fully assessed, but they only cover up to 750. The trader is a right b******d and I know I'll have to get a solicitor involved to try force him into covering the excess.

 

Man.... good luck with your solution.

To me - the easiest way out of this is a replacement, low mileage, known working engine. I've noticed the UK has a plentiful supply of engines and remember you can look into VW's, SEAT's and Skoda's for a replacement engine...

Why? To get to the stage where the piston is able to be removed you've got to dismantle SO much that you might as well swing an engine in and be done with it.

For example - to replace the rings you must remove (and this is simplifying the process...)
- all intake and turbo/exhaust piping
- head (replace all torque to yield bolts and head gasket)
- driveshafts (again replace all TTY bolts)
- gearbox
- remove oil pan
- remove crank (again replace all TTY bolts plus bearings)
- finally you can get to removing pistons (where you need new rings all around.... you typically don't just do the one cylinder at this point)
- if there is damage to the block then you need a new block.... where you might as well have just swung a low mileage engine in.
All of the small, non reusable bolts and gaskets add up! Especially if sourcing from a dealer. Then you add in break in oils, before you use normal running oil where you must change your oil filters each time with each break in oil change. Again, adding up on the total
- go back from where you came from & top up fluids

Now - to replace the engine (with a known low mileage engine)
- all intake and turbo/exhaust piping
- remove driveshafts (replace TTY bolts)
- remove engine and gearbox assembly (replace TTY bolts)
- attach replacement engine to your gearbox
- swing it all back in
- go back from where you came from & top up fluids

That's my 2c

 

I know man but imagine getting another engine for it to throw up problems again. I cant find any TFSI engines under 1500. I wonder how many were trashed now that we know they suffer with catastrophic failures due to carbon build ups etc?!

If I can resurrect the engine for 1200-1500 then I'll go for the rebuild, if not, that trader won't know what hit him, that wasn't just an overnight fault :x

 

good luck on getting quoted up and look forward to updates.

 

I know, minimum 18th of May before mechanics even start up again and very possibly longer, it's crap not being able to get exact quotes!

Would a TTS lump go straight in, if it comes to getting another engine? ECU change?

 

Not sure what your car is currently but yes a TTS engine will physically bolt up.

If the engine is not already a TTS one you will need to make sure it's complete with injectors, turbo, downpipe, boost piping and ecu to make the most of it.

The ecu also needs to be coded to your cluster / keys.

 

Cheers, yeah saw a few cases of Audi contributing towards repairs. The car just had a dealer stamp 'history' with no proper receipts, in fact I have amassed more of a proper history in my ownership. Wouldn't Audi demand a full SH from their main dealers?

I flagged it with the trader I bought it from and the warranty company as it expired 2wks after lockdown, warranty company said they stand over any possible claim when I get it fully assessed, but they only cover up to 750. The trader is a right b******d and I know I'll have to get a solicitor involved to try force him into covering the excess.

A dealer stamp history is something Audi can follow up with the relevant dealer. The key thing is to show it has had regular servicing within their recommendations which are not onerous. The point is they recognise there were some issues with some BWA's and post facelift (as in the thread above) but it is not widespread from what I have researched, and your car is well below a worn out engine in terms of miles. As I said you have nothing to lose.

I would not recommend legal action against a little guy trader post Covid given cost, grief and you may be going after a man of straw.

A TTS engine would be great but it may have had more chance of being thrashed than the base so any purchase of a 2nd hand unreconditioned engine will be a risk without recourse.

 

Not sure what your car is currently but yes a TTS engine will physically bolt up.

If the engine is not already a TTS one you will need to make sure it's complete with injectors, turbo, downpipe, boost piping and ecu to make the most of it.

The ecu also needs to be coded to your cluster / keys.

Just base 2.0TFSI

 

Cheers, yeah saw a few cases of Audi contributing towards repairs. The car just had a dealer stamp 'history' with no proper receipts, in fact I have amassed more of a proper history in my ownership. Wouldn't Audi demand a full SH from their main dealers?

I flagged it with the trader I bought it from and the warranty company as it expired 2wks after lockdown, warranty company said they stand over any possible claim when I get it fully assessed, but they only cover up to 750. The trader is a right b******d and I know I'll have to get a solicitor involved to try force him into covering the excess.

A dealer stamp history is something Audi can follow up with the relevant dealer. The key thing is to show it has had regular servicing within their recommendations which are not onerous. The point is they recognise there were some issues with some BWA's and post facelift (as in the thread above) but it is not widespread from what I have researched, and your car is well below a worn out engine in terms of miles. As I said you have nothing to lose.

I would not recommend legal action against a little guy trader post Covid given cost, grief and you may be going after a man of straw.

A TTS engine would be great but it may have had more chance of being thrashed than the base so any purchase of a 2nd hand unreconditioned engine will be a risk without recourse.

That's his problem, this all started fairly soon after I bought it, he obviously wiped faults and reset the ECU. He's being an a****** about it so he's getting what he deserves and will be going to court no matter what, find it strange you'd pity what's little more than a thief? He was quite happy to take 7K off me.

What kind of prices are TFSI/TTS engines over the water, I see some on eBay but surely there's others that don't advertise there?