Series 3 Oil Pressure Light Spookyness

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olsver

Member
Posts
63
My oil pressure light came on close to home so I stopped the engine and pushed it home. The temperature was normal and it has just had a 20 minute drive.

I checked for leaks and checked there was plenty of oil in the sump and up in the tappet gallery. All looked fine.

I then restarted the engine and the oil light turned off (yay!) ...but after 10 to 20 seconds it turned on again (grrrr!).

I took off the sump, oil filter body and removed the oil pump. There was some carbon deposit and a few flakes of engine casing paint (my fault). I guessed that this muck was clogging the oil pickup screen so cleaned everything out and gave everything a good wash down with spirit.

I checked a few bearings for wear and found nothing. I then reassembled everything and put in a new oil filter, new oil and new pressure switch (a good one).

I started the engine and the oil light went off. After 20 seconds or less it was on again and i'm back to square one. There is new oil in the oil filter body and new oil up in the tappet gallery which makes me think the pump is doing its job.

The engine sounds good. No clanks, bumps or grinding. There is no extra smoke and no funny smell.

Any ideas?
 
My oil pressure light came on close to home so I stopped the engine and pushed it home. The temperature was normal and it has just had a 20 minute drive.

I checked for leaks and checked there was plenty of oil in the sump and up in the tappet gallery. All looked fine.

I then restarted the engine and the oil light turned off (yay!) ...but after 10 to 20 seconds it turned on again (grrrr!).

I took off the sump, oil filter body and removed the oil pump. There was some carbon deposit and a few flakes of engine casing paint (my fault). I guessed that this muck was clogging the oil pickup screen so cleaned everything out and gave everything a good wash down with spirit.

I checked a few bearings for wear and found nothing. I then reassembled everything and put in a new oil filter, new oil and new pressure switch (a good one).

I started the engine and the oil light went off. After 20 seconds or less it was on again and i'm back to square one. There is new oil in the oil filter body and new oil up in the tappet gallery which makes me think the pump is doing its job.

The engine sounds good. No clanks, bumps or grinding. There is no extra smoke and no funny smell.

Any ideas?

Duff switch, new parts don't always work. Or earthing fault on the light.
 
Im sat waiting for a new pump.
Mine came on when I moved it off the drive to let the Mrs out. An hour later I tried it again after checking the oil level and drove it to work no problem. Started it up after work and it was on again. For £85 im not taking any chances and the new pump should be here today. New switch coming also.

Knowing my luck its probably a short. :rolleyes:
 
Right. I'm doing all this in order of lowest cost first. Thank you. Oil pressure gauge is on my shopping list. I'm guessing cam bearing will be the last I try and also the most likely to be at fault (though i'd guess a bit of noise from this but maybe i'm wrong).
 
I always do it the other way round. Only noses run in our family. If it wasnt for bad luck id have none at all.

I got the text it would be here at 2.

Still waiting.
 
I'd still look at an intermittent earth fault on the light first. Unplug the wire from the sender, the light should go out if it doesn't the circuit is earthing elsewhere if it does go out start the engine and see if the light comes on again or Rig up a temporary light using good wire and connections, see if the problem replicates itself. It's cheap and quick to check and it could save you a lot of hassle and expense.
 
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I have now plugged in a pressure tester and I get 0psi. Absolutely nothing.

I know it is rare but could this be a broken pump? The pump turns freely with the spindle. The mechanism feels good but maybe there is more to a functioning pump than free movement.
 
I am re reading the workshop manual. It mentions a gasket and sealant for the pump fitting. I didn't do this. Could that be causing the problem?
 
I have now plugged in a pressure tester and I get 0psi. Absolutely nothing.

I know it is rare but could this be a broken pump? The pump turns freely with the spindle. The mechanism feels good but maybe there is more to a functioning pump than free movement.
what kind of tester and wheres it plugged in
 
The strangeness continues. I took off all the testing equipment and before refitting the pressure switch i started the engine without anything in the hole. I expected a small trickle of oil but it shot out like a firehose and covered the engine bay with oil.

I put the tester on and got 40psi of pressure. However, half way though my i've-got-oil-pressure dance it suddenly dropped to 0 again! Now I can't get the oil yet anymore!

I'm so confused!!
 
I would look at the relief valve and more likely, the drive from the distributor drive gear (which must be turning!) down to the oil pump. There's a quill shaft, and the teeth at either end, or, the internal teeth on drive gear or driven gear can wear, stopping the oil pump.

I don't think this is bearing wear, as it would show up first when the engine is hot, not cold.
 
The oil pump shaft feels firmly slotted in. I can't turn the shaft by hand when it is engaged in the threads up in the engine block. The same goes for when the other end is placed in the pump.

I can look at the quill shaft and gears by taking off the injection pump and pulling the quill shaft out I guess?

All you guys are amazing by the way!
 
Don't be fazed or worried about pulling the injector pump off. Scratch a good line on to help when replacing to save resetting.
 
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