Another oil warning light

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sharpmz
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Another oil warning light

Post by sharpmz »

Hi all,
I've had a good read through the wiki but I can't seem to find anything specific to my issue. I've seen the info about a flashing oil light etc but that doesn't seem to be happening.
Basic summary is that when I start the van the oil light stays on but only for about 5 mins of driving and then dims/flickers and goes out. When the van is properly warmed up the light doesn't stay on if I restart the engine.
I've changed the switch twice and the same thing happens and I'm assuming that because the light stays on and then goes out that the dash and wiring is all ok.
I'm not sure what else to check now as I was hoping it was a switch issue but having tried 2 I guess it's some thing else?
Any help would be really appreciated thanks.
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937carrera
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Re: Another oil warning light

Post by 937carrera »

Can you put your engine details in your signature, people can help more.

Which oil pressure switch have you changed, where is it located on the engine and what value / part number did you replace it with ?

This sounds very very wrong, with the light going out when hot, but on the basis the van hasn't actually siezed will assume that the oil pressure is actually OK.

You really should not have driven the van at all when the oil light was on, It should come on when the ignition is turned on, and go out as soon as the engine starts, even earlier if it is a slow starter.

Answer the questions abpve and we may be able to figure something out
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sharpmz
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Re: Another oil warning light

Post by sharpmz »

Ah yes, sorry. I thought I had save that! It's 1.9dg with just one switch I can see in between the push rods.
I had the same thoughts about not driving it but I put a pressure test and it was ok, the pressure tester wasn't that accurate (cheap one) so I was happy there was pressure and put my mind at rest. Also I'd have expected the lifters to get rattly but the engine runs really smoothly!
Not sure on the part number for the switch. I have actually tried 3 as the first one was off a mates van and I wanted to check that it was an issue with connections. I figured that even with a switch with a different rating the light should behave properly!
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937carrera
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Re: Another oil warning light

Post by 937carrera »

sharpmz wrote: I figured that even with a switch with a different rating the light should behave properly!

Some switches are normally closed, some normally open, that's why I asked which one you have bought. I'm suspecting that you have a DOPS "high" pressure switch in the "Low" pressure hole

Can you see what colour it is or look at the invoice for the part number ?

I'm glad you mentioned you have checked the oil pressure with a gauge, do you remember what pressure you saw under what conditions, more for curiousity that solving this ?
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bigherb
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Re: Another oil warning light

Post by bigherb »

Have you got the correct/decent make oil filter? It should have an anti drain back valve incorporated.
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sharpmz
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Re: Another oil warning light

Post by sharpmz »

I'm 99% sure. It's a Mann filter so happy with the quality. I'm not sure I understand how the oil filter would allow the light to be on then go out when hot? If the oil level is right wouldn't the filter be full because of the angle it's at? Learning a lot lately so any more info on how the drain back valve works would be great!
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Re: Another oil warning light

Post by kevtherev »

Can you take a picture of the engine bay?
It reads to me like the switch has been connected to the wrong circuit.
The switch wire (brown) should connect to another colour (which escapes me doh!)
What colour is yours connected to?
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sharpmz
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Re: Another oil warning light

Post by sharpmz »

That's interesting, it's a black wire on mine and judging by the wiring it's all been replaced at some point but not that we'll. I had a couple of bits done the other day and they may have taken some of the wiring off, so that seems like a good possibility! It's a black wire that goes back to the loom and seems like it goes to the black plastic box on the nearside of the engine bay.
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Re: Another oil warning light

Post by Mocki »

ALARM BELLS!!
all black wires on VW are live +12v

the colour of the wire from the oil pressure switch to the loom is not important ( it was originally brown connecting to the white cinnection block just next to the black box in the engine bay

please state the age of your van , as late and early are different
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sharpmz
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Re: Another oil warning light

Post by sharpmz »

It's an 85, will try and get a pic in a Mo.
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sharpmz
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Re: Another oil warning light

Post by sharpmz »

This is the best photo I could get the yellow block to the far left is the o e that goes to the switch.Image

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bigherb
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Re: Another oil warning light

Post by bigherb »

sharpmz wrote:Learning a lot lately so any more info on how the drain back valve works would be great!
It stops the oil syphoning out of the filter otherwise it has to refill and purge the air out of it through the oil galleries.
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937carrera
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Re: Another oil warning light

Post by 937carrera »

Get a picture of the switch as well if you don't have the part number. :)

OP said there's only one oil pressure switch, so it should be a blue one, and means it's an early WBX engine and van, unless and engine swap has been done.

I think the cable should be blue/black, but if it has been replaced, who knows. Don't forget the light is working pretty much in reverse to what you would expect.

Easy test, disconnect the cable from the switch, ignition on don't start the van, what happens to the light ? Now earth the wire, what happens ?

I'll look at the photo you posted just now
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

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937carrera
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Re: Another oil warning light

Post by 937carrera »

When you say far left, you mean of the engine, not the picture I think ? Can you confirm.

You can do the test by simply unplugging one terminal from the connector, the blue one looks easiest.
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

sharpmz
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Re: Another oil warning light

Post by sharpmz »

Yes, your looking at the right one thanks. I'll get a pic in the morning but it is the blue one. I've put the old one back in as it wasn't making sense.
I'll give that test a go tomorrow but it seems that it's either hitched up to the wrong wire or the oil filter is wrong and it needs one with that valve.


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