Flashing oil light all the time

Hello, a bit of help would be appreciated.

I have a 1983 mk1 golf gti with a later cab engine fitted, I do not drive the car much only about maybe once a month to keep things alive.

I notice on start up my oil light on the dash would flicker very faint on start up and then once revved a few time it would go out.

Now when I start it the oil light flashes all the time, I have changed to sensor on the side of the block but still doing it, I am not very good with electrical issues!

Have also noticed there is only one wire coming from the sender unit which is brown and a stray wire not doing anything which I am thinking is not right?

The car fires up lovely and revs fine, cannot hear any bad noises and have checked the oil level which seems fine.

Any advice would be greatly received as its tad disconcerning driving down the road with the light flashing all the time.

Regards lockstar (Andy)

There should be a yellow wire going to the oil pressure switch. Is your stray wire yellow? The brown, or it might be brown/white if you look closely will be an earth that should be bolted to the head. Note there is another oil pressure switch on top of the oil filter housing with a blue/black wire going to it.

I'll dig out from the garage later but from memory the wire is brown which goes to the sender and also the stray wire is also brown which by the sounds of it doesn't sound normal?
I have not yet replaced the other sender unit lower down but that will be my next move.

Thanks for getting back to me, do you think it could be a faulty fuel pump?

Andy

brown is earth, ground, you don't ground a single pin sender ever.

I don't know if that's a typo and mean oil pump. The only way to know for sure is to get the oil pressure checked with a gauge.

Apologies it was a typo, just dug it out of the garage and the wire to the top sender is yellow and the stray brown wire should be attached to the block,? Which it isn't. would the brown wire not being attached make the oil light flash all the time?

Sorry but I'm a bit of a novice when it comes to car electrics, (ask me to drill open a grade 4 Safe and I'm fine) but electrics is not my best subject!!
Andy

On the older cars the earth for the clocks was connected to the cylinder head. Connect it and see if it cures it

I'll give it a go and let you know, thanks again. 🤞 

Andy

Quick update, I've earthed the stray brown wire and replaced the sensor on the oil filter housing but still no joy, thinking this may be beyond my capabilities.
Any other thoughts?
Andy 

Disconnect the yellow from the oil switch. Does the light stop flashing? You say you've replaced an oil switch, are you replacing it with correct one. The two switches are different.

Hi Steve, I put it away before a saw your message. When I did put away the light started coming on and off very faintly but not flashing, I have bought a new oil filter which I'll wack on tomorrow, when you say take the yellow off the oil switch I think you mean the one on the side of the block? I'll try this tomorrow, I replaced both with the correct ones from gsf.
It is weird it was flashing all the time now it's faintly on and off, I did go for a small drive.

Andy

I'm sure I had the very same problem, the oil light would just come on  but dim and not flashing. This was intermittent and annoying!
I checked everything, senders, wiring all the way to the speedo etc.  I ended up taking the speedo out of the car and I removed the 'L' shaped board that's behind the speedometer.  I was sure it had to be a dry solder joint but couldn't see which one so I re-soldered every solder joint on the board.  This fixed it though and it hasn't come back on since.

 

That's sounds a bit beyond me but I do have a good friend who'd give that a go so I'll have to ask nicely!!

Thanks for all your advice Steve, I'll let you know the outcome.

gee920 said

 I ended up taking the speedo out of the car and I removed the 'L' shaped board that's behind the speedometer.  I was sure it had to be a dry solder joint but couldn't see which one so I re-soldered every solder joint on the board.  This fixed it though and it hasn't come back on since.

 

Over here we call them a cold solder joint.  That is were the solder after application gets hot enough to desolder from the connection but the connection isn't hot enough to flow and cools making it iffy.  This occurs more frequently since they have changed the make up from the solder from 60/40 tin/lead to 60/40 Tin/Zinc….  If you also don't remove the old solder and re-tin or flux clean the connection you may have a future intermittent….. Going though this exact same scenario with a Gent fro Chicago that modified his WESTY GTI to a later Cabriolet style dash, well at least his cars previous owners attempt….

Also on these guy's they do not like Generic Filters, or lower than 10W40 or what I use in my Cabriolets 20W50….

Generic filters, store Branded Filters, Bosch, and Fram all have been known to cause an intermittent blinky oil light from hades…
What I have personally used with no issues are:
STP
Mobile1
Wix
Napagold
PureolatorGold
Mann
Mahl
GenuineVW….

I also add a bit of Zinc to the oil as they tend not to blend it with that itty bit..and can cause cam lobe wear

 

Thanks for the info, going pull the binnacle out at the weekend.
Add some zinc?? 

Andy

There are Zinc additives that you can add to your oil to replace the Zinc that the manufacturers aren't putting in any more,  Castrol doesn't use Zinc….Some High Mileage oils do….. You have to read teh label.

https://www.hemmings.com/stories/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines

https://www.hyperlube.com/blog/engine/the-effects-of-zinc-oil-additives-on-older-engines/

Thanks for the info Briano.

Andy