2.25 diesel - oil light always on...

Hi all,

The oil light on my 2.25 diesel (3mb) won't go out...

It's full of oil, to the point it usually is (H on the dipstick, anything less and the light stays on), but the light is still on... the light usually comes on with the ignition and goes off once the engine is started, the only other time it usually comes on is under heavy braking, facing downhill or it sometimes flickers at idle. I changed the oil recently and used Halford 20w50 classic, it does burn (and/or leak) a bit of oil but nothing major so I've just been topping it up as and when.

I usually only do 4 x 3 mile trips a day in it, so lots of short journeys all at low speed (max 40, downhill ) but I went greenlaning in it last Saturday (loved it!), this involved a few miles of dual carriageway - so near max revs for the old girl, I first noticed the oil light on Saturday night. Before topping up the oil I noticed the rocker cover, and sump gaskets have been leaking badly, probably from Saturday. I tightened the sump and got about 1/2 a turn on each bolt - seemed a bit loose... got a few turns on the rocker bolts too, then topped up the oil to the usual level. I then turned the engine on but the oil light didn't go out, I put another pint in to see what would happen and the light still hasn't gone out... it's now overfull and burning oil though.

I might as well admit, I've been a bit of a tit and wasn't paying attention on Saturday, the dash lights are quite dull and I was having too much fun laning, and so I have no idea how long the light has been on. The oil was down to the L on the dipstick on Saturday though.

Is this as simple as a duff pressure sensor or have I buggered the engine? I'd like to get this solved sharpish as the MOT runs out on Friday so any help is appreciated!

Cheers

youy need to check pressure and actual amount in it and that dip stick is correct ,then look at pump if needed

jamesmartin said:

youy need to check pressure and actual amount in it and that dip stick is correct ,then look at pump if needed

Click to expand...

So I need to buy a pressure gauge then? Darn...

Any recommendations as to which one?

Cheers

Drop sump off and see if the mesh over the oil pump intake is blocked. Thats where I would start. Could always be a faulty pressure switch but best to check everything to make sure

Simple things first - they cost less Personally I would do a oil & filter change. Mine seems to like 20w 50 as recommended. When did you last replace the filter? Next would be sump off to check the pick up isn't blocked. If you ran low or got at some exciting angles laning, you could have picked up some crap from the bottom of the sump perhaps?

I've heard the tube that the dipstick sits in is often not 'calibrated' properly, easiest way to check, is look in the book and see how much the engine needs (6liters without filter change, 7 with I think) drain the engine and pipit what the book says back in, personally, my oil level has been just below 'L' and no oil pressure light (good job I check regularly) but it does turn on when starting (as it should)

I had the sump off and cleaned the gunk out (wasn't much in it tbh), changed the oil and filter back in January this year so there shouldn't be any crud in it, will have a check though.

To be honest if the sump needs to come off I might as well whip the engine out for a minor overhaul as it's a bit tired anyway. Was hoping not to spend much money on this as I'm saving for a 200tdi... ah well...

Cheers!

Dont go for britpart seals if you change them, I made that mistake on one of them (the front crank seal). Went a grand total of 25 yards before it started leaking badly again. Sorted now though

Nah I've had enough of britpart already - but that's another rant...

On a side note, the MOT runs out on Friday, but this could take a while to fix...

If the truck is taxed and insured, but no MOT do I need to sorn it?
It's tax exempt and I'll get nothing back on the insurance so would be easiest if I can just leave it...

Check wiring first. It may have rubbed through and be shorting somewhere, then try swapping. Switch....

Freetime101 said:

On a side note, the MOT runs out on Friday, but this could take a while to fix...

If the truck is taxed and insured, but no MOT do I need to sorn it?
It's tax exempt and I'll get nothing back on the insurance so would be easiest if I can just leave it...

Click to expand...

I think it will be OK, but ring the DVLA first. They are very helpful.

Cool thanks, will give them a shout

Get a non electric oil pressure gauge...screw it in were the oil pressure switch goes...I would not mess with anything till you have done that and know where you are...

This may do...

Car/Truck Wave Box Oil Pressure Meter Test Kit Gauge Diesel Petrol Garage Tool | eBay

Post back with the results.

Freetime101 said:

On a side note, the MOT runs out on Friday, but this could take a while to fix...

If the truck is taxed and insured, but no MOT do I need to sorn it?
It's tax exempt and I'll get nothing back on the insurance so would be easiest if I can just leave it...

Click to expand...

no sorn needed. Sorn only applies to tax (and effectively now insurance as you must not have a taxed vehicle without insurance)

Cool thanks, that makes life easier.

I've had a play with the electrics and I'm confused... there is only 1 wire going to the sensor, if I unplug this the light stays on. If I short the wire direct to the negative battery terminal (skipping sensor) the light stays on... surely the light should go out with one of these options?

Looking at the wiring diagram in the Haynes manual, the light should go out when the sensor is unplugged? If this is correct I guess I've got a short somewhere?

Yes when you unplug from oil pressure switch light should go out. Suspect cable has chaffed against something creating a direct short. Good luck locating

Tim

TBHI2 said:

Yes when you unplug from oil pressure switch light should go out. Suspect cable has chaffed against something creating a direct short. Good luck locating

Tim

Click to expand...

Cool thanks, hopefully a cheap fix then!

Maybe easiest to run a new wire?!?

Were it me I'd be looking for the short. If you've got a clamp abraded thru the harness wrap finding it now may save more trouble later as more wires get cut and messed up.

One thing to look for is the connection at the dash - might be something as simple as anabraded wire at the lamp socket or something similar.

ajr