High oil consumption on Passat TDI ?

I have a '98 Passat TDi 110, with nearly 70,000 miles.

The car is good in every way, but the oil consumption is on the high side. I reckon I am getting through 1.5 to 2 litres of oil every 10,000 miles, just keeping it up to the line.

I know diesels do naturally use oil, but my wife has a '98 Golf with the 90bhp TDi engine (60,000 miles), and this consumes probably 1/2 a litre over 10,000 miles. I find that I am always topping up the Passat, but hardly ever adding to the Golf!

Is this excessive? - and does it indicate any sort of engine issues? - or am I just paranoid!?

Both the cars were bought as 1 year old used cars, so while they have perfect main dealer service histories (with fully synthetic oil for the last 3 services on each), I do not know how well they have been cared for before our ownership.

Mine uses something like 1 1/2 litres over 10,000 miles too, and I am using fully synthetic Miller's Diesel oil.

It is a little annoying, but I wouldn't exactly call it excessive.

Put it this way, if the oil changes were 5000 miles like the old IDI diesels, you would hardly notice it.

I have a similar rate of oil usage with my car, which has the same engine; even with Delvac-1 synthetic, I've been averaging 1.5 litres/16000km. My car is an A3 Jetta.

Not to be an arse or anything, but you should check out the poor folks driving the 2.0 gassers over at the Vortex. Regularly you see people with 1 and 2 year old cars talking about losing 1.5 - 2 litres every 1500 miles or so. Nobody can ever really tell where it's going, and everybody's VW dealership tells them that a loss of a litre ever 1000 miles is normal.

That said, assuming you don't have any visible leaks on the outside of the engine, you generally lose oil in two places. First is through the CCV system which unfortunately sprays oil mist into the intake with the blowby gasses. If you do a search on intake manifold cleaning you'll see lots of pictures about where that ends up. The second place is valve stem seals, though we don't have it as bad as the gassers because our higher compressions don't seem to let as much oil through.

Drivebywire recently suggested that he's seeing wear on the camshaft seals when doing timing belts, which should be checked as oil will be very detrimental to the life of the timing belt.

All in all though, having owned VW's for so many years, I wouldn't say that your oil consumption is at all excessive. Dubs just like the keep their oil fresh I guess...

I use about 1 litre per 10k miles, although I can say with a good deal of certainty that good portion of that winds up in my inlet tract, via the CCV, not being burned through the rings or something like that. That is now fixed!

Some people have near ZERO consumption and that's great for them, but the rate everyone in this thread is seeing so far is by no means a matter over which to be alarmed. Think about it: 1 litre per 16,000 kilometers. That would have been unheard of even only a few short years ago.

We had our consumption go down dramatically when we switched from Rotella dyno oil to synthetic. Part of that is a result of the lower volitility of the synthetic oils.

High revs before the engine warms up is also thought to burn more oil. And the warm up does take a long time.

Dyno oil can also lead to sticking piston rings.

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Bookerdog:
The second place is valve stem seals, though we don't have it as bad as the gassers because our higher compressions don't seem to let as much oil through.<hr></blockquote>

I think that it is because the diesel engine is unthrottled. When the throttle is closed on a gasser, then during the inlet stroke there is actually a massive vacuum in the cylinder, which sucks oil past the valve stem oil seals. On a diesel there is atmospheric pressure (more or less) in the cylinder during the inlet stroke, and so the oil does not get pulled past the valve stem oil seals.

Thanks for all your comments, this puts my mind at rest. I am coming to the conclusion that there is naturaly variance in oil consumption between VW diesels.

When does the bulk of your oil consumption occur? Is it uniform throughout the change interval, or does it get progressively worse as you get more miles on it?

the consumption appears to be uniform. occasionally, i will forget to check my oil level for 2 months (say 4000 miles), and it is often getting close to the minimum mark.

For the last 2 services, i have been using american Chevron Supreme 5W-40 fully synthetic, as it is far and away the cheapest VW 505 approved full synth I can get hold of in the UK (at £11.75 for 4 litres - Mobil 1 costs over £30 in comparison!).

I use Millers XFE synth.
Its a bit more expensive (but less than Mobil 1) and comes in 5 litre cans, but it is a diesel specific oil, and so is the best that money can buy, as far as I am concerned.

Is the Chrevon a diesel oil? or just a general purpose petrol / diesel oil?

From looking at the Millers website, the XFE is a semi-synthetic blended oil, whereas the XFD is fully synthetic.

Chevron Supreme is a general oil, not diesel specific. However, the oil has the VW 505 spec on the side (and the VW manual says any VW 505 oil is acceptable), and is 5W-40 rated, which matches the oil the main dealer would otherwise supply.

On the occasions where I have asked the main dealer to supply a fully synthetic, they offer oil called Synta Gold (I think), which is also a general VW505 5W-40 engine oil.

I would be interested in knowing what benefit there is to the turbo-diesel specific oils?

[ November 22, 2001: Message edited by: bigdave764 ]</p>

Millers keep changing the name, first it was XFE-synth, then XFD, now XFES. The website is always a bit behind what they really sell.

Diesel engines attack their oil in a quite different way to petrol engines, which is why I prefer a no compromise diesel specific oil.

Sorry for not getting back sooner Dave. My ISP is "improving service". I think this means hold on to your arse and your checkbook, but we'll see...
Usage that increases toward the end of your oil's lifespan would tend to indicate the additive package is breaking down and you should shorten your drain interval. But, in your case, I wouldn't sweat it. Since it's consistent, it can be just the way it was broken in, p.o. used fram air filters, or in one case I know of in particular, all the ring grooves were lined up on one cylinder. It's probably something mechanical but benign, if it doesn't change over the years (months) Don't sweat it.
Our 97 Passat uses like your Golf. You're right to be concerned, but at this point it's cheaper to do nothing. The oil costs less that re-ringing to save roughly 1-1/2 litres per 10000mi.If it goes up worse, you might wish to do something about it, but at this point you are kind of at the borderline for your car. Try not to forget to check it so as not to miss events if consumption goes up suddenly. I have a Cat that is expected to be fine until it uses more that a gallon a day. Whew!

All,

When my 96 tdi passat wagon started using oil at 23k miles, a large amount of oil was found in the intercooler. After replacing the turbo under warranty the dealer replaced the breather valve, the round plastic thing on top of the engine. The oil consumption then dropped back to zero. Even with rotella dino oil at 107k miles it didn't need any between changes. My 99.5 jetta with 67k using delvac-1 does not use any between 10k changes eather. So if it's using oil pull the lower intercooler hose off and if oil runs out suspect the crankcase breather valve.