Vauxhall Astra oil warning light

[Markbon]

I have an Astra Estate 1600 cc 16v GLS (R reg) and the oil light on the instrument panel regularly illuminates. The dipstick has previously indicated that there was no oil at all in the engine - however on putting in one litre (which would usually only take it from the min to max on the dipstick) the dipstick now shows there is far too much in (which indicates there was plenty of oil there before) This has not stopped the oil light illuminating regularly (and staying on). Could this be a problem with the oil light - or dipstick? There is no indication of any oil leaks and it does not appear to be burning oil.

[New Forester]

Measure the oil when the engine's been standing for a bit -- this gives the oil a chance to drain down to the sump.

 

Is this an oil level light, or an oil pressure light?

 

If oil level and the dipstick shows it's OK, then it's a dodgy sender unit.

 

If it's an oil pressure light, could be also a dodgy pressure sender, or more likely could be low oil pressure -- from very worn bearings (perhaps from no oil previously) or a knackered pump.  I presume you haven't an oil pressure gauge as such?  An oil pressure light should go out very soon after the engine starts, stay out while running, and ideally should stay on for quite a while after it stops (stop engine, turn ignition back on and watch light).

 

Get a garage to test the oil pressure, and don't drive it too much beforehand, as low pressure will not do your engine much good!

 

[MORELLO]

I've got an Astra and they can be a pain in the arse at times. I wonder if there's a problem with your oil pump, although drainage to the sump, where levels are monitored, should be automatic. Tough one. Does the engine run hot? I get some irregular dipstick readings and you can't rely on the first one, but I'd look more towards a fault with the sensor...

 

Crap answer, but just letting you know I feel for you man! .

[Ian H]

I agree with New Forester, that if the warning light is indicating low oil pressure, then its one of two things : low oil pressure or the sender is faulty and needs replacing. A big clue to whether it is low oil pressure- the light flickers on when the engine is fully warmed up & is idling. If you increase the revs slightly, the light may go out. If the light is flickering with normal driving it & does the same at engine idle then it has to be the sender. Hope that helps- a little knowledge from a few engine rebuilds..