Oil warning light and alarm.

[Bucky P]

Hi, I've got a T25 1.6 turbo diesel van and just recently the oil warning light/ alarm has been coming on. This usually happens when decelerating after cruising, it happened several months ago when it came on for about a second and then went out, I checked the oil and it was normal, it never happened again until about a week ago. We went away in the van for the last week and this same thing occurred several times, normally when slowing down in traffic or turning off at a motorway junction, etc, this normally only came on for a second or two. When coming home yesterday it happened again just the once but it stayed on, I pulled into a motorway service station for a few minutes and shut the van down, when I started him up again all was clear, the oil level was ok and we continued our journey with no further alarms.
The manual tells you to shut down immediately and seek advice if this happens so it is obviously a potentially serious problem, can anybody advise me on what the problem is so I can get this fixed ASAP.

Many thanks, Paul.

[Ian Hulley]

Low oil pressure ... the sensor(s) seems to be working as it/they should. So the alternative is a weak oil pump OR a knackered bottom end, the way to really tell is to have a garage check the oil pressure.

I know/want to know nothing about diesel T25s so will leave it at that.

Ian

[Bucky P]

Thanks for that Ian, I'll get it checked out.

[kit]

When did you last change the oil? My old engine would buzz if I didn't use 20 50.

[Bucky P]

Probably about a year ago, its due for a service soon.

[kit]

That could be the problem.

[Ian Hulley]

When did you last change the oil? My old engine would buzz if I didn't use 20 50.

In a petrol waterboxer using 20w/50 is a head in the sand approach, if it buzzes on 15w/40 you use 20w/50 to hide the issue as the oil is thicker.

[kit]

He has a JX diesel and I only used until I replaced the engine.

[Reimotim]

I had exactly the same issue. The garage checked the oil pressure and said it was fine. They've changed the sensors and that seemed to solve the problem.

[Ian Hulley]

They've changed the sensors and that seemed to solve the problem.

No, the time the buzzer is coming on is correct for times when the oil pressure drops ... this time it's dropping into the sensor's alarm range. Oil change is #1 priority and if it persists get the pressure checked properly.

Ian

[King Kenny]

My warning light came on after hard breaking at a pedestrian crossing. It soon went out, but when I stopped I found oil dripping under the engine. By the time I got home it was quite a gush. When I crawled under the van I found oil was passing through the oil pressure swich electrical contact between the pushrod tubes.

[Ian Hulley]

My warning light came on after hard breaking at a pedestrian crossing. It soon went out, but when I stopped I found oil dripping under the engine. By the time I got home it was quite a gush. When I crawled under the van I found oil was passing through the oil pressure swich electrical contact between the pushrod tubes.

That's a failed sensor.

Ian

[King Kenny]

I know. I got a new one and all is well !

[bootie3367]

After reading the user manual (in german) one thing i noticed was the range of oils that can be used.

I checked on the graph temperature thingy and according to that (for the JX engine) if your in slightly warmer climes then 20/50 is the way to go.
Not knowing what oil was in mine when I bought it I changed it for that anyway.
when I drove the van home from purchase it was about 300km, last bit was all uphill (15km) and very twisty, that's when the buzzer of doom came on, strangely only round right handers uphill. First time it happened I stopped and let it cool down, started up again and was fine for another few km's then it happened again same thing, round a right hander uphill. Managed to get her home OK, changed the oil next day and she's been fine ever since.
I've spoken to the guy that sold me the van and he postulated it could be due to the shape of the sump and the crankshaft 'splashing' the oil when cornering causing aeriated oil to be picked up therefore giving low pressure. Is that likely or was he pulling my plonker????

Do I go to the extent of fitting an oil pressure gauge to check what's happening or not?

Jon

[colinthefox]

Your adviser makes a good point. It's likely to be oil frothing and/or surging. If you have a bit too much oil in the sump, the crank dips in and whips it up to a froth. When you brake hard or go round a long bend (or both at a roundabout) the oil slops to one side and the froth gets sucked up by the oil pump. The froth turns back to liquid quite soon after revs are reduced. The problem gets that much worse with a 1.9 conversion, I assume due to the longer stroke. I just wish I could see inside the engine to confirm what was happening.

But if you have not enough oil in the sump, the oil slops to one side and the oil pump sucks air.

[E D I T]And that's all with a good oil pump and good oil[/E D I T]

I'm currently experimenting with the combined sump gasket and baffle plate, (from the Polo1.9D) which seems to be specially designed to stop the crank dipping in the oil. I'll report back when it's thoroughly tested.