High Oil Consumption

 Our 57 plate T5 has started over the last 9 months to regularly use 1 litre of oil every 700 to 800 miles. Is this normal?  Why could it be happening?  Are VW responsible for engines for more than 3 years?

VW can say whatever they like, including that 1l oil/600 miles is "normal", but most people would regard that as excessive oil consumption and an indication of something wrong with an engine.

Which engine ? 

Is the performance still OK (ie unchanged from when the engine wasn't using excessive oil) ?

Doing a dry then a "wet" compression test can give an indication if the piston rings are worn (and therefore leaking oil into the combustion chamber to be burnt).

IIRC some of the 4 cyl VW TDI engines have a bit of a reputation for using oil (often rings), but they usually use it right from the start.  If it was OK at first, but then suddenly started to use a lot of oil I would look for the cause.  Possibly turbo seals as Rebuild says.

The 5cyl 2.5l VW TDI engine doesn't have such a reputation for using oil unless it leaks out somewhere (turbo, oil cooler, power steering pump). 

Look for lots of oil in the intake plumbing (not just a thick coating, but large puddles of oil) for a turbo leaking oil problem.  This can be dangerous as if the engine starts to run-on on the engine oil it can go into runaway mode where you can't stop it.

If the oil cooler (or its seals) leak your pink coolant will go black/grey from engine oil.

If the p/s pump leaks the p/s fluid is black/grey instead of the normal clearish pale green.  The steering is usually a bit odd with vibrations on lock etc.


Edited by gregozedobe - 02 Dec 11 at 05:42

 Thanks .   Is it said to be normal consumption, do you know loads of people who do refill? Could it be aussie heat?  

Using lots of oil isn't the norm, but it seems VW 4 cyl engines do use more than average.  I don't think it is anything to do with Oz heat. 

One thing that can catch people out is that engines that do lots of short runs can have a build up of condensates in the engine oil, which disguises an engine that is actually burning a fair bit of oil.  Then when they go for a good run on the hwy (where the engine gets properly hot for 30 minutes or more) these condensates are boiled off, leaving the oil level low and the owner thinking their engine is suddenly using a lot of oil.  It hasn't, but now they notice it (especially if the oil warning light comes on).

The missing oil has to be going somewhere, so unless it is dripping on the ground (or engine undercover), or is somewhere else in the engine bay/underneath the van then it must be being burnt off.

Again I ask, is the performance of the engine unchanged ?  No funny idling, hesitations, excess smoke etc ?  How about fuel consumption ?  Any other issues, or is it only excessive oil consumption ?

A straight compression test can be done with the engine in situ, but it isn't as easy as on a petrol engine as there aren't any spark plugs with easy access.

I'd be tempted to get a written report from a good independent mechanic.  It might save you quite a bit of money, as it could be that your dealer is softening you up to pay for a complete new engine.  Kmowledge is power in these situations.

First look at how much oil is in the intake after the turbo (possibly intercooler), if there is loads (big puddles) of oil then the turbo seals are the prime suspect.  Note that there is normally a fair bit of oil in the intake tract of VW TDI engines.

Then a dry followed by a wet(engine oil) compression test.  If it is a bit down dry but improves when oil is added that usually indicates a problem with the piston rings.

Having both of these tests done should cost you way less than £500, and you will have independent corroboration of what might be wrong.  IMO this is what your dealer should have suggested to you .

caveat: I am not a qualified motor mechanic and this advice has been provided free of charge, so the usual "all care, no responsibility" principle applies.

The only way turbo seals could make any difference to starting is if the normal fuel supply wasn't working properly (not uncommon on T5s) in which case the extra fuel (ie engine oil) from the leaking sealsmight make it a bit easier to start.  

Edited by gregozedobe - 05 Dec 11 at 13:34

hi,