Oil pressure HELP

[Luc]

Seeking some answers to why the oil warning light comes on in my 93 4x2 Hilux with 22R engine.

Heading home at night a week ago and with 5 kms to go the oil warning light comes on. Stop engine, plenty of oil, no sign of leakage, start up engine & as no weird noises, continued on home & got there no problems having driven 15 kms from work.

Very experienced mechanic friend confirms plenty of oil & no weird noises, suggest may be some gunk on the sensor. over the weekend, degreased engine and did full oil change including engine flush. Started engine, light went out and didn't come on again until Monday when nearly at work. Again, plenty of oil & water and no visible leakage from engine. Also, at no time did the engine smelt like it was running hot.

Returned home later that day with light on all the way. Checked again, plenty oil, no leaks and no overheating. Mechanic friend's opinion is that the oil pressure sensor is gone.
Friday, put ute into repair shop to have new sensor fitted. After collecting it, drove around for a while and no light.

This afternoon, while shopping, light comes on again. Checked and plenty of oil & water and no leaks. Returning home after shopping and after 10 minutes or so light' on again. Stopped for more shopping and this time light came & stayed on as soon as engine turned on & stayed lit until home.

So given new sensor, oil & water OK, no leaks and no weird engine noises, any other causes?

[jamesmcjim]

unplug oil sensor when light is on and engine running. light goes out means problem with sensor or oil pressure is low.light stays on means wire has short to earth somewhere.

[Boofhead03]

If you disconnect the wire from the oil pressure switch does the light go out? The wire might be shorting out intermittently onto something?

[Luc]

Thanks for the suggestions.
Will try disconnecting the oils pressure sensor in the morning.

Hopefully a short.

[Gon Fishun]

Hook up a pressure gauge to test pressure.

[tunaticer]

Try cutting off the electrical connector that goes to the sensor and replacing it. Could well be a bad connection.

Has the engine ever had a blown head gasket or similar that has let water into the oil?
If it has it is entirely possible a bit of hydrolised oil is gumming up the oil sensor port as well.

[rayken1938]

As gon Fishun said your mechanic mate should be able to unscrew the sensor and connect oil pressure gauge.Whilst sensor is out blow out oil lines may just be a bit of gunk or else gunk is blocking filter on oil pick up for the pump. Otherwise off with the sump and inspect pump etc.
Cheers
Ray

[Luc]

Thanks for the additional info/suggestions.
Mechanic mate will do the pressure test.
Have never had a blown head gasket and used oil flush before doing oil change last weekend.
Oil was dirty but no evidence of any water or any sort of gunk/sludge/solids.
Oil pump runs of crankshaft and is located in front of the timing chain cover so if it needs replacing it shouldn't be too much drama.

[tunaticer]

Pull the sump off and check the screen over the oil pickup is not blinded.......a few of the latest common rail diesels are having this drama I see.

[Luc]

Hi tunaticer, engine is an ULP burner.

I'll add that to the check list.

[Greg P]

Ease up - do the oil pressure check first with a gauge and make sure your mechanic mate runs it till it is at operating temp. Also get him to pressure check the cooling circuit once warm to make sure it is holding pressure. If that is ok I would be looking at the oil pressure switch wiring circuits for an issue before removing the sump. Should be a pretty basic troubleshooting flow for your mechanic to isolate.

cheers

greg

[Luc]

Oil pressure check scheduled for this Tuesday.

We'll see from there.

[Luc]

Latest update.

No problems with the oil pressure test.
Mechanic's opinion is that there's probably some muck interfering with the sensor.
He recommended another oil/filter change with double dose of flush and running the engine for an hour before draining the oil.
Will be doing that Sunday.
PS the warning light hasn't come on at all for the last coupe of days.