vanisveryrusty wrote:All VW vans have a red oil warning light. Contrary to common belief, the oil warning light has nothing to do with oil level. I get calls from people all the time who remark that their oil light is on, but they just checked the oil level with the dip stick and it was fine. That is not the way this warning system works. Rather, the red light comes on when the oil PRESSURE drops too low as determined by an oil pressure switch installed on the engine. No VW van ever came from the factory with an oil pressure gauge or oil level indicator, just a low oil pressure warning light.
VW TECH PAGES>GO WESTY.
Just curious, why do you get calls from people regarding their oil lights are on?
better ask Go Westy thats was who i was quoting.
as stated in post
Well that shows your oil was as cold & thick as it's ever going to be, and it wasn't leaking back to the sump. Or your pressure sender is knackered.
I've have been trying to think of a way that adding oil could cure power loss, and I have a theory. If your oil level was so low that you partially seized the engine. Maybe it got hot enough to jam the piston rings into their grooves. Once the engine cooled down the piston rings stayed compressed meaning you lost a big chunk of compression. Later when the oil got topped up that was enough to lub the rings and they popped back out restoring your compression and fixing the loss of power.
I know you thought my comment about replacing an engine was a bit glib but I as a minimum when I changed the oil I would have strained it through a fine mesh to look for metal debris.
Looks like I was lucky then.
Although I have an oil pressure senor to replace ?
I kept the oil and have just strained it, no metal.
Compression test fine.
Van runs well.
Maybe our engines are tougher than we initially think
Explains why it never came on when oil was at a couple of pints and resultant oil pressure would of been zero.
There are two sensors ?
Which one do I go for first, or is it best just to change both ?
I thought they normally failed in postive mode, flashing and buzzing when pressure was ok, rather than just not coming on at all ?
On engines fitted with two switches
High pressure switch (0.9 bar) is between the oil pump and oil filter (line pressure, and main bearing feed) (buzzer switch)
the low pressure switch (0.3 bar) is between cyl 3 & 4. (lifter gallery, upper oilways) (light)
they work in harmony connected in series ... one is open circuit and one closed circuit by default and the circuit continuity checked against an approx 2000 rpm break-point. The way it's wired, one is being monitored above that speed and the other below it.
They are colour coded and Brickwerks sell them.
Thanks Kev
Will check conections first, and PCB connector under dash pod.
I am pretty sure it worked OK a few weeks back, but I have let someone else drive it since then, so I dont get daily checking time.
until something busts
And of course you can test the low pressure sender and the lights wiring by simply using a short bit of wire and using just your fingers, earth the terminal of the low pressure sender to a bright bit of metal on the engine (with ignition on but engine not running). If the light then comes on then that sender is faulty, if it does not come on then the wiring to or from the light is faulty. Let us know.
Mind you, this single flash when you turn the ignition on is still odd and right now I cannot think what the cause might be, unless a previous owner has been "modifying" it's way of operation for "some" reason
ghost123uk wrote:Mind you, this single flash when you turn the ignition on is still odd and right now I cannot think what the cause might be, unless a previous owner has been "modifying" it's way of operation for "some" reason
Could it be a bad connection at the pcb connection under the dash cowl ?
There is evidence of windscreen leaking and it has been raining recently......
Maybe its single flash is the fist of a series of flashes which would make it "normal", just that its not connecting properly aftr the initial flash.
I'm pretty sure I saw it flash until the engine started a few weeks back, which is normal i think.
Daughter has been using van since then so my daily checks only come into play when things are suspect.
Lucky me
vanisveryrusty wrote:
I'm pretty sure I saw it flash until the engine started a few weeks back, which is normal i think.
You're not getting it muddled up with the coolant warning light, which does flash and then go out, are you ?
I wish I was .
No. Certainly not.
That one is still operating as designed.
Just for clarity then:
On accesory position what should the oil light be doing ?
Because mine blinks once and goes out.
When engine is started it remains out.
When engine stalls, it remains out.
The light should be lit with just ign on
turning the starter may be enough to extinguish it (it depends on turnover speed and oil condition)
Should it fall below 0.9 bar over 2000 rpm it will flash & buzz
should it fall below 0.3 bar at tickover it will be a constant light
Cuts out all the annoying twin pressure switch over engineered buzzing flashing not lighting at all malarky doesnt it.
Just what were VW thinking of !!!!!!!!
I might do the same if the van stays still long enough over a weekend so I can get my hands on it.
When ignition is on at accesory position it apears briefly once for about half a second and then goes out.
I have checked the wiring behind the dash pod and cleaned up the earth crowns behind the fusebox just in case they had anythingto do with it.
Waste of time that was.
vanisveryrusty wrote:Cuts out all the annoying twin pressure switch over engineered buzzing flashing not lighting at all malarky doesnt it.
.
It does but the guage gets looked at.. and then consequently becomes something to worry about..like when your cooling system (which affects oil temp) starts to play up, and the pressure plummets alarmingly at 65 mph
so you think about oil coolers and that bottomless pit just got a little deeper
with lights you are blissfully unaware of the impending engine death...you can't win.
I have just the light at the start, after that I'm on the guage..
