where's my oil gone?

[zorak]

Ok my oil level has gone from top of the full line to the bottom of the low line on the dipstick in the last 1-1.5k. I filled it up to full again and the process repeated.

Is it normal to burn oil like this? ( it has nver lost a ml before this) or is there something more sinister. Any ideas? There is no leakage on the floor either...

[JBT]

Any signs of smoke from the tailpipe?

[sirbob]

When are you checking the oil? Is the motor on the flat and has the engine been turned off for several minutes?

Just a suggestion, am sure you've been doing that already, either way, if you are losing that much oil there is somthing wrong. Have you changed viscosity recently? If so i would reccomend going back to a thicker 15W30 or something...

[zorak]

Cheers guys - no smoke and I am currently on castrol edge 5w 30 - might change to a thicker oil next change. And yes, I have been checking the oil on a flat surface after the engine has cooled off a bit.

[JBT]

How many km travelled on Castrol Edge?
What oil was used previously and for how many km?
Any stale burnt oil odours when the car stops at idle?
Anyone checked at the tail pipe (not from inside the car) for smoke on start up or after prolonged idle?
Any oily deposits on the plugs?
PCV valve working properly?

[zorak]

The car has done 70k km and I have always used synthetic oil with 5k km changes.
I originally used shell then mobil 1 15-40 and then switched to castrol about 15k km ago (so the last 3 changes) after mobil 1 got too expensive. Now that think about it I dont think its the oil because there was no oil usage for the first 10k kms on castrol (5w 30).
Plugs look fine
whats the pcv valve?

[Babalouie]

whats the pcv valve?

If you look at the driver's side of the cam cover, there is a rubber pipe that goes to the inlet manifold. At the cam cover end of it is a plastic thingy (the PCV) which is a valve of sorts to regulate the "breathing" of the crankcase gasses into the inlet manifold (for pollution control reasons).

IMHO it's sort of a bit of a long shot to answer your oil consumption question, but when the PCV breaks, sometimes it can allow oil to spurt into the inlet manifold and hence you burn it (well that's the case in some cars). The reason why I say it's a bit of a long shot is that there are internal baffles inside the cam cover that prevent a splash of oil from climbing into the PCV pipe quite that easily.

[JBT]

Steve, There would be oil all over the place if Zorak leaked 800ml in 1500km. CAS oil leaks run all over the rear of the engine and down the bell housing

I know someone who is having a similar issue with an NB8A but it is now giving the odd plume of blue smoke from the exhaust after prolonged idle or when power is applied after mild engine braking conditions. It also has developed the dead engine oil smell on shutdown or at idle prior to shutdown.

It's unlikely to be the PCV valve but it is the cheapest possible problem area so worth a look.

Some other possible candidates are:

1. worn valve guides,
2. stuffed valve seals
3. stuffed rings
4. glazed cylinder walls

Might be worth getting someone to check at the tail pipe (not from inside the car) for smoke on start up, after prolonged idle or on the road.

[Babalouie]

Steve, There would be oil all over the place if Zorak leaked 800ml in 1500km. CAS oil leaks run all over the rear of the engine and down the bell housing

I know someone who is having a similar issue with an NB8A but it is now giving the odd plume of blue smoke from the exhaust after prolonged idle or when power is applied after mild engine braking conditions. It also has developed the dead engine oil smell on shutdown or at idle prior to shutdown.

It's unlikely to be the PCV valve but it is the cheapest possible problem area so worth a look.

Some other possible candidates are:

1. worn valve guides,
2. stuffed valve seals
3. stuffed rings
4. glazed cylinder walls

Might be worth getting someone to check at the tail pipe (not from inside the car) for smoke on start up, after prolonged idle or on the road.

When my car was using 1L of oil a week it was because the engine was totally stuffed with only 135psi compression

If you like, we can do a compression test on your car and do a proper diagnosis, I'm on the nth shore.

[zorak]

Babalouie I take it you are a mechanic? I am on the nth shore too so that might be helpful - thanks.

[Babalouie]

Babalouie I take it you are a mechanic? I am on the nth shore too so that might be helpful - thanks.

No I am a lawyer.














But I am a lawyer who owns a compression tester

[EGG80X]

Babalouie I take it you are a mechanic? I am on the nth shore too so that might be helpful - thanks.

.

YAY dodgy day at Kev's

[Babalouie]

Babalouie I take it you are a mechanic? I am on the nth shore too so that might be helpful - thanks.

.

YAY dodgy day at Kev's

More like Dodgy 5 Mins cos that's how long it'll take to comp test his car

But yeah, why not? If you want to verify the comp of your car (and are you sure that you do?) come along

[rodent]

w00t I'm in for Babalouie's Dodgy Compression Test Day!

[sirbob]

I was using castrol edge 5W30 and found that my NB was burning a fair amount of it. I think the 30 is a little light. I then changed to mobil 1 5W-50 and had no worries after that, only very small amount of missing oil after hard drives... (assumed most of it was lost during cold starts)

However, the amounts of oil you are talking about are interesting... to go from full to empty in 1500km is a lot of missing oil.

Personally i would upgrade to the castrol edge 10W whatever, you'll not burn as much and your tappet noise will be reduced on cold starts....