Oil light on when in neutral / idling

honda boi

So my cmax 1.6tdci oil light came a few weeks ago. It was due an oil change so changed it and the light went off.
But now its coming back on .
It seems to only come on when the engine is idling or when I put it into neutral.
I'm thinking oil pump is on the way out but thought the pressure would be wrong all the time if it was f**led but then again when the engine is revved the pressure must increase to normal psi.
Any other ideas? Maybe the sender unit? Or is it definitely oil pump?

gctest50

You need to put a test gauge on it

rex-x

It could be a few things but it doesn't sound good if it goes off when revved. Remember the oil pump doesn't actually make oil pressure, it just provides a volume of oil to the bearings etc, the pressure is made by the clearances between the bearing shells. Its very possible your engine is worn out (although certainly not guaranteed) If I was you I would get a manual gauge on and go from there, might be worth dropping the sump to check for sludge also.

mullingar

+1, you need to get the oil pressure level.

As mentioned above, the oil pump just pushes volume into the engine. If the gaps in the engines moving parts are too large, the pressure can never build as it should. Revving the engine pushes a larger volume into the engine, hence building the pressure so light goes off.

All engine manufacturers specify what the oil pressure range should be at X or Y rev (when hot).

You could try to replace the oil pump to see, but it's a messy job. Oil pan and timing belt must come off.

But to do it right the crankshaft and camshaft and its bearings will need to be removed to be inspected and measured. One area that needs to be checked is the camshaft bearing on the end nearest pulley, it sits in a cutout on the engine head, if this cutouts get worn you need a new head as it's part of the head (I've seen this a few times)

George Dalton

First thing to do would be remove the sump and check for sludge buildup. Very common issue on these engines. Can also cause the oil pump pressure relief valve to stick.

honda boi

Sound lads
First will get an oil pressure gauge, measure oil pressure.
Then will drop the sump and clear out the sludge and go from there then.
Do you think its safe to drive the way it is now?
(By keeping the revs past 1,000 rpm the whole time,oil light goes off , I know sounds stupid doing this)
Won't be able to get out to it for a day or 2 at least.

honda boi

Also hoping it wouldn't be sludge issues as cars engine was put in about 27,000 miles ago ,a year and a half ago and mechanic had cleaned the sump and the other bits before he put this engine in.
I've changed the oil every 6,000 miles since so I'd be be pee'd if it was sludged already,tho I know this engine sludges like crazy.

rex-x

I wouldnt even attempt to start it let alone drive it to be honest

honda boi

Well lads just to update ,got the car sorted.
Had a day to go over the whole car.
For a few weeks the car was down on power and smokey.
I thought it was a leaky injector.
A few days after posting this it had basically f all power in it so I decided to tackle everything.
I took the injectors out,there was oil all over them!!
I took the cambox of as I wasn't sure if it was diesel or oil that had began to leak.
In the pic I attach you can see my old cambox on the left,the part that held the chain together and kept everything in sync had actually snapped off and there was pieces of it by the valves !!
The one on the right is the replacement one I got.
I put her back together, started her up and by god she sounded brand new!.
I've never heard it sound so good:p
I have a feeling this cambox was f**led from the day I got it.
Oil light was still on,so I changed the oil pressure switch and woala it turned off
Car running better then ever now.

honda boi

Another update:
Oil light was appearing again,not a frequently but would still come on while driving.
And when starting the car it could last up to 30 seconds!!
Got time to tackle it yesterday ,
Changed the oil pressure switch in case the small chance it was a faulty one. Nope didn't make a difference.
Dropped the sump.
Pieces of the plastic piece that was destroyed on the cambox were down in the sump.
Also a lot of metal pieces,meaning bearings where touching at some stage.
Never would of thought this as the car is running as smooth as ever when I changed the cambox.
So cleaned the sump and the oil drainer as they were covered and blocked with metal pieces.
Put the sump back together and was advised to dump some engine treatment in it and hopefully will do the job.
Bought 2 bottles of redex oil treatment ,put both in engine,added oil.
Started her up and now the light goes out after half a second,drove for half an hour and no oil light!!