EA288 2.0 TDI Compression pressures

[Ben_T]

Hi all, hope I've posted this in the right place...

I've got yet another vRS CUPA engine which is guzzling oil. 1 litre per 1,000 miles typically. I've tried using different brands of oil (including stop-smoke jollop), re-routing the crank case vent, removing the injectors and repeatedly filling the cylinders with decarboniser to clean the piston rings, all to no avail. It's on 154 k miles now.

The intake's reasonably dry and the the turbo exhaust outlet's bone dry so I don't think it's turbo or crank case vent related. Which leaves the piston rings or valve stem oil seals.

I've tested my compression with a cool engine and am getting 320 PSI (21-ish bar pressure) on the number 1 cylinder.

Has anyone else tested their compression on any of the 2.0 TDI EA288 engines and if so, what did you get? I'm planning to take the engine apart in the near future but don't want to disturb the head gasket if the rings can be left alone. Thanks in advance!

[Crasher]

Common EA288 problem, we fit a genuine exchange engine (£7628.18 retail, inc VAT) or turn the job away as the parts and labour required just don’t add up. If the labour isn’t included then it can be done BUT you must not reface the head, only replace it if distorted, we would use an AMC casting. Depending on VIN the usual cause is the EGR cooler breaking up inside and damaging the bores.

[Ben_T]

Thanks so much for your reply! And for your advice on the cylinder head, I'll bear that in mind. I'd heard of the EGR coolers ruining Transporter engines but didn't know it could affect mine too.

I'd be doing the rebuild myself, so even with the absence of labour costs it may still not stack up financially by the time I've factored in the cost of the hair transplant I'll inevitably need afterwards. Not a nice engine to work on.

A friend's got one with 63 k on the clock and good service history which also uses a lot of oil, so a low-mileage second hand one probably doesn't make sense either. Decisions... Peugeot o' clock?

Thanks again

[Crasher]

I am casting around for a new car, the only thing that fits the factors is a Bentley Arrange T but Mrs Crasher says no

[mickeybo]

what checks if any was done to check out valve stem oil seals

[Ben_T]

Haha! I see what you mean. I suppose everything has problems. Choose your poison...

[Ben_T]

Good question! In truth, none. Trouble is, with the car having a DPF it isn't possible to start the engine from cold and then rev it momentarily to check for smoke. I'd have liked to have taken the turbo/inlet manifold off to visually check for leaks, but it's not a quick or easy job to do this at all.

The one thing I have done is to analyse the exhaust hydrocarbon content during driving from a cold start. It starts off very low (as you'd expect for a healthy engine), then gradually rises to a very high peak after about a mile. It then gradually drops off again as the catalysts warm up. High revs and/or full acceleration give the biggest whack of oil in the exhaust fumes, even if the engine's hot. The thing is, it never smells of burning oil, only of hot oil. It's almost as though the oil's migrating its way into the combustion chambers and then evaporating, rather than actually burning. Still plenty of ash residue on the glow plug tips, injectors, DPF etc. though.

I suppose I'm over-analysing it. I'm planning on disassembling the engine in a month or so and I suppose I'll see what the state of affairs is then.

[Crasher]

The lambda sensor is easy to take out

[Ben_T]

The lambda sensor is easy to take out

Nice idea, thanks! I've not long replaced the sensor actually so it should come out easily. I'll report back...

[Ben_T]

Well, I thought I'd make the most of what's left of the good weather and disassemble my engine to get to the root cause of its oil consumption issue

So, as a recap, here were the symptoms:
- Oil consumption of 1 litre per 1000 miles pretty much regardless of the oil brand/viscosity rating
- Very poor cold starting (5 seconds plus of cranking) during the warmer months. Much better when cold and the glow plugs are operational
- Compression on the #1 cylinder of 21 bar (320 ish PSI)
- Loss of power; according to VCDS's calculations, my car produced a maximum of 344 Nm of torque at the road wheels. I repeated this with a friend's CUNA engine with no oil consumption and it reported the expected 380 Nm
- VERY crackly when cold (warm weather, glow plugs not operational). Worse after sitting undriven for a few days, as was the cold starting
- 160,000 miles with sketchy service history (at least 20 k miles between oil changes). Originally a non-fleet company car..

I've now disassembled the engine and found the following:

- No turbo shaft play detectable
- Intake system almost dry
- Valve stems dry on both the exhaust and intake sides (except one which had a very slight weep)

I think this indicates the PCV and turbo were not the culprits.

- Valve faces covered in thick, tan-coloured oil ash deposits
- Piston crowns covered in thick oil ash deposits
- Piston skirts around 50 % of teflon worn through. Polished in the central area of skirt, horizontal lines missing
- After removal of carbon deposits, cylinder bores lipped
- Cylinder bores polished at bottom 1/3 of travel. Honing just visible in upper 2/3 of piston ring travel
- Ring marks visible on the bores at upper limit of ring travel

- Top compression ring end gap of 0.3 mm at top of bore (0.37 ish mm at bottom). Haynes says 0.3 to 0.4 mm new, wear limit 0.55 mm
- Second compression ring end gap of 0.5 mm at top of bore (similar at bottom...). Haynes says 0.2 to 0.45 mm new. Wear limit 0.95 mm
- Oil scraper ring end gap of 0.73 mm at bottom of bore. Haynes says 0.25 to 0.50 mm new, wear limit of 0.75 mm
- All above on the #4 cylinder

- Oil scraper rings completely occluded by carbon deposits. Almost all holes totally blocked
- Oil scraper ring spring tensioner uneven coil spacing throughout

- Conrod upper bearing shells worn down to the copper, approx 100 µm thinner than lower bearing (which looked as new)
- Cylinder head toast due to snapped glow plug with screw extractor snapped off in it (my fault). Sealing fine, but doesn't like cold, cold starts so much. Can't drill out due to hardened steel extractor.

So that's that! It seems as though the bore's slightly wider at the bottom, but this is based on end-gap measurements as I don't have bore measuring tools. Again, the bores are also polished at the bottom.

I didn't measure the piston ring groove clearances because I didn't want to.

What's caused this is unclear. Maybe the long service intervals? Thrashed by original company owner? Engine not strong enough to withstand 181 BHP? Or a combination of these?

I'm not sure if this will help anyone, but hopefully it might. Incidentally, the two engine flushes and decarbonising fluid I poured directly into the cylinders last year don't seem to have touched the scraper ring deposits.

I was hoping I could re-ring and re-assemble but this seems unwise now due to the cylinder bore lips. Decisions decisions. Thanks for reading.