Engine using oil, and dirty plugs – is my turbo oil seal leaking?
My 1996 A4 B5 1.8 T has done only 30,000 miles, but uses quite a lot of oil, and the spark plugs always have oily carbon deposits on them. It is also slow to start, taking 2 or 3 seconds cranking before it fires, whether the engine is hot or cold.
The oil consumption has been about 1 litre per 2,000 miles since I bought the car early last year, with 25,000 miles on the clock.
Re. Slow starting.
In case this is due to a faulty engine temperature sensor causing a rich starting mixture, I checked indicated coolant temperature with my VAG 1552. It shows the temperature as ambient before starting, and gradually rises in a normal way.
I recently replaced the thermostat, and the temp. gauge shows 90º when driving.
I put in new spark plugs, but this made no difference.
In case the N80 valve is faulty, causing the EVAP canister to discharge into the inlet during starting, causing a rich mixture, I blocked the hose from the N80 valve to the air inlet, but this made no difference during several starts.
Re. Oil on plugs/consumption
As mentioned in previous posts, I removed and checked the PCV valve for the crankcase. It is working properly, and there is no positive crankcase pressure evident when I remove the oil filler cap at idle.
Today I measured compression pressures with the engine hot, all plugs removed and HT coils and injectors disconnected, expecting possible low values to indicate excessive blowby, but values are way above minimum.
Specs are: Minimum pressure – 7 Bar, maximum variation 3 Bar.
Results: Cyl’s 1 to 4: 13.3, 13.8, 13.8, 13.9 Bar.
All the above seems to indicate that the engine is OK, so is it likely that the plug oiling and oil consumption is due to a failed turbo oil seal?
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
Good compression doesn't mean that the piston oil rings are not seated, a better indication of this is to use a cylinder leak down gauge but that is more involved, a low mileage on that age suggests possible bad storage, short running times etc and these can cause bore wash which glazes the bores and stops the piston oil rings working. Check in the turbo outlet pipe at its lowest point, if it only has a little wetness then the oil isn't coming from the turbo compressor shaft and into the intake. Technically speaking a turbo shaft doesn't have seals, they use steel piston rings, just to confuse...
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
Thanks for that, Crasher. Badly seated oil rings due to low mileage from new seems very probable; the car never seems to have been used much, and was certainly stored for much of its life.
Somewhere in my brain I knew turbo oil seals are metal:confused:
The first owner died some time ago, probably around 2001, and his widow drove it even less, if at all.
It seems it was used by her nephew, but not registered in his name until he sold it to me last year.
It costs about £200 to register it, so he didn’t do this until he sold it to me.
Here are the dates, mileage and mileage since previous service (converted from km) from the service history booklet which came with the car. The last item was done by myself.
29/04/96 Delivery service
15/05/97 12mth 4723 4723
12/08/98 12mth + Int 8210 3487
01/10/99 12mth + Int 9886 1676
10/10/01 12mth 13948 4062
21/02/05 ? 17683 3735
08/07/08 ? 19641 1959
13/02/16 All items 26883 7242
It seems glazed bores are the most probable cause of the oil being burnt.
I checked inside of the pipe from the intercooler to the inlet manifold when I was replacing the belts. It had a slight film of oil on it, but was not dripping with oil.
I’m getting a bit crippled, old, and lazy, so I’m not going to drag the front of the car off yet again to check the turbo right now. Everything runs nicely and very quietly, plenty of power, so maybe I’ll just stop taking it apart to find out why it runs so good – as my old uncle used to say, and hope the rings eventually seat themselves.
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
You could try Millers Glaze Bust oil and then run it on Motul 4000 15w/40 mineral oil until/if it settles down, it has worked for me on a number of occasions.
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
I managed to get the Glaze Bust at the end of August, but didn't get around to putting it in the engine until today. Following the data sheet instructions here LIQUID GLAZE BUST | Millers Oils - Advanced Lubricants, Oils and Fuel Additives
As the total oil volume of my engine is so small (3.9 litres), and filling it to the minimum level without changing the filter, as instructed, took only 3 litres, I filled it to the maximum, which took 3.5 litres. I bought 8 litres of Glaze Bust, and am unlikely to need it again, so there seems no point in economising on it.
We then drove briskly for about 40 miles on the main road, to a nice restaurant for Sunday lunch. I checked the oil level when we arrived, as I expected to be using more than usual, but the level had not changed.
After eating (and only 25 cl of wine each) we returned via minor roads through the hills, so that there was plenty of gear changing for the auto box to do, and pulling away uphill after slow corners. Arriving home we had done about 80 miles. The oil level has still not noticeably dropped.
The instructions say to keep running on it for maximum of 200 miles or until oil consumption reduces, but the engine is not using an appreciable amount of oil, so I am wondering whether I should continue the process until I reach the 200 miles, continue for less than that, or change to the Shell 15W40 mineral oil which I have ready.
Am I likely to do any damage by leaving the stuff in any longer, Crasher?
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
I would do the 200 ish, it is just that it lacks the cleaning agents normal oil contains. Finding mineral 10w/40 is proving VERY difficult.
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
Thank you. I will do as you suggest. I hoard all sorts of stuff, including oil:D
I still wonder what to do with a gallon or two of Castrol 2T two-stroke oil I have. I bought it years ago, to experiment with adding it to the Ro80's petrol, and disabling the oil dosing pump (which feeds oil into the petrol at the carbs). It seemed to work OK with the oil:fuel ratio I chose, but I got nervous about myself or wife forgetting to add it when filling up, and reconnected the dosing pump.
My feeling was that burning two-stroke rather than engine oil would cause less carbon build-up on the rotors, which was the main cause of sticking gas seals.
Someone actually marketed a metered two-stroke oil injection system, with the oil pumped from a dedicated tank instead of from the engine lubrication system, but by then I had ditched the NSU engine and fitted a Mazda.
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
Quote:
Originally Posted by
FrenchAudi
I had ditched the NSU engine and fitted a Mazda.
:puke:ohh well, better than a Ford V4 which is what most people fitted
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
Quote:
Originally Posted by
Crasher
:puke:ohh well, better than a Ford V4 which is what most people fitted
It was a Mazda rotary engine, producing 175 HP instead of 115 from the NSU engine, with much lower fuel consumption, which is what NSU should have produced if VW/Audi hadn't ditched the Ro80 and taken over the factory in Neckarsulm.
1 Attachment(s)
Re: Engine using oil, and dirty plugs – is my turbo oil seal leaking?
After filling with Millers Glaze Bust in December, I ran 250 miles under varying conditions, and have now been running on Motul Classic 15W/40, as recommended for running-in, for 170 miles. We don’t go far at this time of year, as the Audi is mainly used for longish trips, so it’s taking a while.
In those 420 miles there has been no noticeable oil consumption, but I will wait a bit longer before I decide whether or not it has really been reduced.
I see from the parts list that there is a plastic box assembly at the start of the breather system, bolted on the side of the block, called the “Breather Assembly”, item 1 below.
I assume this contains an oil separator/baffles/mesh to reduce the amount of oil reaching the air intake?
Does anyone know if this item needs servicing on a regular basis? - It’s a bit inaccessible.
I have seen a few reports of the plastic “Breather Line”, item 2, p/n 058-103-213, connected to the Breather Assembly, becoming brittle and splitting. A later version, p/n 06A-103-213-F, looks more sturdy, may be made of metal (is that too much to hope for?) and should be a direct fit.
This is my breather system:
Attachment 34675