Oil light on

Hello

I converted my Mk1 to 1.8t about 6 years ago. Everything ran great. No issues. 
But since having children 3 years ago the Golf has sat in the garage with a few hours spent on it every 6 months or so. 
I'm having another push at it but now the oil light is on constant. It flickers like it wants to go out but doesn't. This was not an issue before. 
In the 3 years I have changed the coolant setup, had the clocks out and in and done a service. 
All I can find on the forum is flashing oil light and buzzer. But mine is just constantly on without the buzzer. 
What is it warning me?

Thanks in advance, Skipp

The low oil pressure switch on the side of the head can get gummed up, as the buzzer is controlled by the switch on the oil filter flange (white).
The low pressure Pressure gauge is the can on the side of the head, and the oil temp switch is on the oil filter flange single pin black.

Too thin oil, wrong vis and a cheap generic/storebranded/Fram or Bosch filter will case the low pressure blinky light from hades.

As with most of the 4Cyl cars that I have owned for the last 50 years I have used either 10W40 or 20W50 oil in along with a good filter (WIX) and everything other than VW's I used Mahl, or Mahn(SP) filters as well as the others I will list, and never seen a flickering oil light.
Wix
NapaGold
PureolatorGold
STP
Mobil1
Mahn
Mahl
GenuineVW

If you have the bunged off additional port on your oil filter flange, then you can try moving the one on teh side of the head to either it or the oil temp sender, and change the bung or temp sender to the side of the head.


It could also be now that I have my head out of my posterior happens as after thought while typing,  If you have not run your car for a few years, add some SEAFoam engine treatment to the Gas and the engine oil as your oil pump by-pass can be crudded up and on instead of closed..

After owning my cars an seeing increased temps of the oil running down 140F roads with the a/c on… I did a couple of things, one replaced my senders (don't go cheap by good ones.) and installed a external oil cooler to my rides.  The 90ish Cabs I have owned over here (US) never had the oil temp  water jacketed stabilizer sandwich plate .  So I used a thermo controlled Whaler plate from a VOLVO, and an external cooler to lower it.

After installing the External cooler I never saw my oil temps exceed 105C temps.  When prior to that I have oil temps run 130-200C.  Nw these are temps off the console gauges at 80mph for hours running with the a/c on full chill on roads in the south being baked by sunlight for half a day, and the roads were at least 150 degrees on the sunny days.

Also Check or replace your major grounds on the car that is from the battery to frame and frame to engine.

IIRC the spec for oil pressures at idle are temp 80C, and engine reved to 2K, you should see 2 bar pressure, anything lower then you are looking at bad cam/crank/intermediate shafts or them being crudded up (which is where SeaFoam or Marvel Mystery oil in the engine crank cases removed the varnished up stuff) or a bad Oil Pump.

If you are going to the oil pump change, I would urge you to install the beefier 2.0L pump as the Pump Teeth are taller 36MM vs 32 IIRC.
 

So a constant light is oil pressure?
The engine is quite low mileage and the wiring harness was cleaned up while converted. 
I have used the Quantum oil recommended by VW with a Mahn Lupo GTI oil filter. This is what I used before without a problem. 
The car has been regularly started but I had stripped a few bits off when refitting the coolant system. 

Could be your wiring as it's an engine conversion or a faulty sensor or even low oil pressure.

Have you got the port to plug in a laptop to see if any fault codes throw up or maybe take it to a garage and get them to hook up an oil pressure monitor and see what pressures you have.

Ok so I started the car again and there was no light. Then after about 10 minutes of idling it started to come on dim and got brighter. When I shut the engine off I left the ignition on while scanning for faults. The oil light flickered on and off irregularly. 

No faults on the computer other than the 1s I expected from deletes. 

So I have a 3 bar VDO gauge in the centre console but it's not wired because I don't have a sender. So my next question is if I get a 3 bar sender where will it go? In the oil housing? What thread am I looking at for the sender?

Thanks again. 

Have you dropped the sump and checked the pickup pipe?

20vt yeah?

No I haven't dropped the sump. But I replaced the sump with a shallow 1 and cleaned the pick up pipe then. I can't have done more than 4,000 miles since. I suppose it's not impossible that something got on it in that time so I can drop it and check. 

Yes 20vt. 

skipp said

No I haven't dropped the sump. But I replaced the sump with a shallow 1 and cleaned the pick up pipe then. I can't have done more than 4,000 miles since. I suppose it's not impossible that something got on it in that time so I can drop it and check. 

Yes 20vt. 

Was just a though dude. When I first installed my 20v in my mk2 I rushed and fitted the engine without doing the pickup and it had the same symptoms as you. 

I dropped and the pickup was gunked up, so was a lucky save. 

But if you've done it that recently, I very much doubt it's the pickup. 

Yer this is why I'm thinking if I get my oil pressure gauge working and can see there is a genuine issue I can then start looking in to the reasons. I will start with dropping the sump though. 

Thanks

I would get a Mechanical gauge on it and see what the pressure really is before I tried to dink with installing a electrical gauge.

Oil pressure sender single pin green or brown blue is for low pressure. White on filter flange is for low pressure high rpm.  

Most oil pressure senders I have seen are dual that is low pressure, and pressure gauge (can type with 2 tabs) on side of the head, and don't think the low cost generics are good value cause they usually don't work.

60-100USD are usually good ones that last a wee few years.

The car hasn't been started for 2 days. When you turn the ignition on but not start the engine, should the oil light be flashing?

What thread size are the senders?

Thanks

yes