Low oil pressure

R

Roy

Member
My wife's A2 started to show the low oil pressure warning light. She thought it was low on oil so topped it up but that didn't cure it. It needed a service and cambelt change, so that's just been done - but the oil pressure light still came on. The garage has tried a new oil pump and that hasn't worked either. The garage have rung to say they're investigating and are suggesting taking the engine apart to find the fault. The bill is climbing day by day so any suggestions as to what the problem might be so I can point them in the right direction would be very gratefully received.
Details: 02 reg, 1.4 petrol, 49k careful miles.
Thanks, I hope someone knows what might be wrong...
 
Hi Roy, welcome to the A2oc.
Did the garage check the oil pressure with a test gauge before changing the oil pump. If not, it could be a faulty oil pressure sender, which is not uncommon - http://www.a2oc.net/forum/showthread.php?t=12894&highlight=oil+pressure
If the presssure has been tested then I'd be tempted to remove the sump and check the oil suction tube to see if it has come loose, is cracked or there is sludge/debris blocking the strainer.
If they find a problem then its worth checking a main and conrod bearing for damage while the sump is off

Cheers Spike
 
Thanks for the quick reply Spike. I'm fairly sure they said they'd tested the pressure but I'll confirm that with them when I see them tomorrow. If so, I'll mention the points you suggested.
 
Quick update. Pressure was tested with a gauge. Bottom of the engine all checks out OK, nothing loose, missing or blocked. Where should they look next?
 
If the actual oil pressure is good and the sender is good, then surely the fault lies either in the control unit that processes the signals from the sender, or its associated wiring (plugs, connectors, crimped joints, etc) ??? That would be my next stop anyway......

Cheers,
 
Thanks for the reply Lee. My post obviously wasn't clear. The pressure test gauge showed that the pressure was indeed low, as the sensor says it is. But the more obvious causes of low pressure (faulty pump, blockages etc) are all checking out OK.
 
Ahh... Sorry Roy.. I misunderstood.

Oil pressure is normally take directly from the outlet of the oil pump or thereabouts, so if they have changed the pump and it is still low, there is something very odd going on. I must admit, I too would be checking things like dented sump (restricting pick up pipe, cracked/loose pick up pipe, blocked/clogged strainer, etc etc.. in other words, all the oil feed components...)

I am not sure how the pump works in the A2. Is it possible that there is some kind of NRV in the line that is faulty, or maybe if the pump is driven from the crank via gears, maybe they are worn or slipping.... or even if the housing of the pump is worn and clearances have increased.

I am assuming there is no external oil leakage, say from the filter housing or the filter itself or turbo main bearing oil feed unions or oil cooler unions?

It does indeed all seem a bit odd....

EDIT: Just seen an oil pump for an A2 on e-Bay and it seems to be a part of the front engine block cover and driven directly from the crank shaft. There must be a mechanical pressure regulator somewhere. Could this be worn/damaged causing low pressures?
 
Last edited:
Roy said:
Thanks for the reply Lee. My post obviously wasn't clear. The pressure test gauge showed that the pressure was indeed low, as the sensor says it is. But the more obvious causes of low pressure (faulty pump, blockages etc) are all checking out OK.
Click to expand...

Hi Roy
There is quite a fiddly procedure for fitting a new oil pump. This involves setting the crank at TDC then aligning marks on the oil pump inner rotor before slotting everything together.
Can't work out if the new oil pump would still work correctly if the process was not followed but its worth asking the garage if they did it to the book.

Cheers Spike
 
My 1.4 petrol started showing the low oil pressure warning light. Unfortunately I was in the middle of a long journey so couldn't get to a garage. I checked the oil level but was convinced the sensor was faulty.

End result: main bearing was done, engine failure. With 85.000 miles on the clock, I managed to sell it for repair for about half what it was worth. Gutted.
 
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