Oil pressure warning coming on @2300 rpm; Golf '95 TDK@210000

[$hitblast]

Well, every three weeks or so, this car gives me another challenge. This time it's the oil pressure alarm and light going on @2300 rpm or so. It's got enough oil, at maximum level, actually, and does not seem to leak, so that does not appear as the problem. There is no chiming at lower rpms and the engine operates smoothly no matter load or rpm, with the alarm sounding or not. No change in temperatures either. If I let go of the accelerator just when the alarm comes on, it will sometimes stop ringing. The problem has persisted for three days now. I changed the oil pressure sensor sitting on the oil filter bracket about three months ago due to an oil leak through it, and I'm thinking this was the low-rpm-sensor. This fix was successful as far as I can tell. Might this be the high-rpm-sensor being faulty?

Sorry about the last post, I forgot to complete the headline.

[vdubmotorworx]

it might be the oil pressure itself....get the pressure checked with a guage...if its low then look at a blocked filter or sump pick up / worn oil pump...if the pressure is ok the look wiring / sensors...VDUB...

[Transporter]

as above, but It could also be worn out bearing somewhere. The diesel engines are known to perform well until the second they die.

[gldgti]

Having the oil pressure alarm come on at higher rpm and not lower goes against all mechanical logic if there is actually an oil pressure problem, as far as I can see.

I would do 2 things:

1) Install an oil pressure gauge, use a T from the sensor hole in the end of the head to take the signal. Every old diesel should have an oil pressure gauge anyway, so its a good idea. This will tell you definitively if there is actually a problem or not.
2) Check all of your accessory brackets, injector pump, for vibration when you rev the engine up. Just rev it up in the engine bay manually moving the throttle lever on the pump, and put your other hand on the pump/alternator/ac pump etc. I have seen VE pump diesel engines to VERY strange things due to vibrations, and the vibrations seem to come from broken brackets and mountings for various engine accessories. I think its a remote possibility that something like this could cause your oil pressure problem. Remote, but possible. In particular, check the bolt at the back of the injector pump underneath the injector line outlets.

[$hitblast]

Much obliged, VDUB, Transporter and once again gldgti. Well, I checked the contact on the high-pressure sensor more thoroughly this time, and it turned out it had seeped some oil into the contact from the previous leak a few weeks ago. I cleaned it, rammed it up to 4000 rpm, and presto; no alarm. This I did with the engine at about 50 degrees celsius, but I'm guessing this does not have much to do with temperature. It turned out much less costly and simple than expected.

[$hitblast]

Well, I took it for a spin, and it turned out nothing had changed, the light and buzzer came back on while under load @2300 rpm. While still waiting for the oil pressure gauge, I changed the oil-filter with a new MAN-filter I had lying around. With the new one in, I passed 15 kms of highway at speeds above 100 km/h and rpms well above 2000/min with no problems. Then, in a sleek climb, at about 2400 rpms, fifth gear, the alarm set off again. This was not the first, nor the steepest incline, though. Before changing the oil-filter, the alarm would go off within a few seconds of rpms around 2300/min. Why would it take so much longer this time?

[$hitblast]

..and today I tried it for vibrations, with my brother at the wheel, watching the tachometer. Holding my hand on the motor-block, diesel-pump, alternator, front engine-mount and oil-filter, they all seemed to vibrate equally much, and at the same frequency, as my brother varied the engine speed between 2200 and 2500 rpm. I'm pretty sure there where no cracks in the mounting for the injector-pump. It did not seem loose. I tried jerking it, put it stayed put. I could not see the bottom bolt, though, maybe because of somewhat bad lighting.

[Transporter]

You are probably losing a valuable time, since this could be an early stage of an expensive failure. Just test that oil pressure and take it from there.
A bearing that could be worn out can cause the oil pressure switch to set the light On. Think about the garden hose, now turn the tap on and partially block the end of the hose with your thumb, you will feel the pressure and you can spray water quite far, very similar is situation in the engine lubrication system where when the clearance (the gap, your thumb at the end of hose) between the bearings and moving surfaces that are connected with the oil galleries is at specified tolerances the pressure is maintained and the lubricating oil flows to all moving parts. Now, for example if there would be worn out cam shaft bearing - going back to the flowing garden hose with your thumb maintaining the pressure and flow too, if you move your thumb to make a bigger opening at the end of the hose simulating bigger gap between the camshaft and the bearing you would feel less pressure and water will not spray as far.

The engine will work for some time with faults like these but the wear will increase and also spread to other components, longer you leave it more it will cost to repair the damage.

I could say the above in much shorter sentence but wanted you to think more about the relationship between the pressure and flow in fluids.

Now, get that oil pressure tested, just for a peace of mind.





Sent from my GT-N8000

[gldgti]

you are probably losing a valuable time, since this could be an early stage of an expensive failure. Just test that oil pressure and take it from there.
A bearing that could be worn out can cause the oil pressure switch to set the light on. Think about the garden hose, now turn the tap on and partially block the end of the hose with your thumb, you will feel the pressure and you can spray water quite far, very similar is situation in the engine lubrication system where when the clearance (the gap, your thumb at the end of hose) between the bearings and moving surfaces that are connected with the oil galleries is at specified tolerances the pressure is maintained and the lubricating oil flows to all moving parts. Now, for example if there would be worn out cam shaft bearing - going back to the flowing garden hose with your thumb maintaining the pressure and flow too, if you move your thumb to make a bigger opening at the end of the hose simulating bigger gap between the camshaft and the bearing you would feel less pressure and water will not spray as far.

The engine will work for some time with faults like these but the wear will increase and also spread to other components, longer you leave it more it will cost to repair the damage.

I could say the above in much shorter sentence but wanted you to think more about the relationship between the pressure and flow in fluids.

Now, get that oil pressure tested, just for a peace of mind.





sent from my gt-n8000

this!!!!^^^

[Lito]

X3!! Being stranded on the side of the highway due to no oil pressure and dead engine is not fun or cheap trust me, I know. I'd be double checking the pressure with a mechanical gauge before I drove it at all. I do hope it's nothing too serious though mate.