My car (95 Cav, X20XEV lump) has gone from needing no oil top-up between changes (7000 miles) to needing a litre about every 3 weeks. AFAICT there's no leak to the outside, so it must be leaking into the cylinders and burning, yes?
What's likely to be wrong, and how much will I get fleeced for to put it right? It's a DOHC so will any valve problem require the head off?
Ta
Pete
If you're sure there's no external leak (including from the rear oil seal into the clutch housing - it should drip out of the bottom if the drain hole is clear) then it must be burning it. Are you getting a lot of blue smoke? I would expect this with this level of oil consumption, if it's not a leak to the outside. It may be a head leak into the cooling system. Have you looked into the header tank or reservoir for signs of oil?
If it's none of the above then it's difficult to tell without taking bits off. A sudden rise in consumption is unlikely to be general wear such as you'd get on the valve guides, for example. So probably something has broken. The bits that are responsible for controlling the oil are things like piston rings - even the pistons themselves - and valve stem seals. A broken oil control ring (one of the several rings per piston) would allow quite a bit of oil to get burnt off the cylinder walls without unduly affecting the performance of that cylinder. You might need to do a compression test to see if this would throw up some clues.
Based on the above, can you give a bit more information?
Rob Graham
There's no dripping at all - I park on a clean driveway overnight and have looked for the telltale signs. Also, no new oil around the filter & sump area or round the block ,as far as I can see.
Can't see any from the drivers seat, neither on start-up nor when revving. I'll get someone else to have a look when I start it.
The coolant is fine
About 18 months ago the only time a garage has changed the oil (while replacing the sump gasket) they overfilled it by about a litre. I noticed about 2 weeks later. Will this have over-pressured the system & blown a seal? If so the higher consumption has been a long time coming.
Another thing - at the last oil change I put in semi-synth whereas I'd always used fully synth before.
It's due an oil change, should I run a flushing compound through or is this likely to worsen the situation by loosening crud that is currently sucessfully stopping leaks?
Ta
Pete
As a cross-check you could take out the spark plugs and see what they look like ...
Might, but unlikely.
Very true.
Did the high consumption start soon after you'd changed the oil? How many miles has the engine done?
I wouldn't have thought you'd need to flush it. I agree that might make things worse if anything. Question is, where's the leak? We need to know whether your burning it in the cylinder/s - blue smoke.
Rob
The oil was changed about last July, I've only done about 7k since then. The car has done 120k total - I would expect some oil consumption, just not as much.
The Vx dealer recommended semi-synth so I'm going to use this now.
Not checked yet...
Pete
Haven't done so yet, certainly worth a look.
Thanks
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.