Oil pressure switch - no wiring

Post by **medenview** » 07 Dec 2011, 19:42

I have just taken my 1990 G reg T25 into my local garage, used many times for various faults on her.

This time it was for an oil leak, mechanic thinks it's at the oil pressure switch which he will replace, but he also found that there
was no wiring connected to the switch and he couldn't find any loose wiring at all. Is it easy to insert new wiring to replace the
missing cable? I'm only asking for my own information, hoping the mechanic knows the answer already.

Cheers
Simon

Post by **Rich Tea** » 07 Dec 2011, 20:28

Hello Simon,

You didn't say what engine you have..... so I'll assume it's a WBX 1.9 or 2.1.

Most I believe have two oil pressure sensors, one by the left hand bank of cyliners and one hidden down behind the crankshaft pulley on the water pump side. I think early models have only one.

I have had leakage issues here (leaking through the core of the sensor) so best to replace. Be careful where you buy from though, I've had brand new ones leak (Euro car parts or GSF, can't remember which). I suggest you buy from Brickwerks.

On a two sensor model you're looking for multi plug (two spades) at the front left of the engine. One wire is green with black tracer (left hand bank of cylinders) the other I think is brown or white (sorry can't remember).

One big concern is that they've been disconnected, or the wires earthed to prevent low oil pressure warning the so called "buzzer of doom" read the section on low oil pressure in the wiki to learn more about this dodge.

If it's a different engine some of the above will be wrong.

Cheers

Rich

Post by **medenview** » 07 Dec 2011, 22:36

Sorry it's a 1.9 water cooled, DG engine if that helps

Post by **ermie571** » 08 Dec 2011, 06:19

Same as mine mate....i have the late 2.1 inserted into an EARLY (ie A Reg) 1.9 originally van. Therefore the engine has the two pressure sensors, but the van only has the wiring for the one switch down by the push rod tubes. This is a blue single spade swtich.

I know this, as I have just changed it due to the very same problem as you. Switch soooo old that the oil was coming through the switch...not out around the thread!!

The oil light comes on with the ignition, and goes out as soon as its running. But no Buzzer of Doom, cos the van's electrics don't support it.

Em
xx

Post by **kevtherev** » 08 Dec 2011, 07:31

if it is the low pressure switch then it must be replaced with the blue 0.25 bar M10 X 1 (available from brickwerks) connected to a black/white wire
the other switch is black 0.9 bar M10 X 1 and uses a green wire
both connectors are in the engine bay left
the wiring, routing, connections and their respective colours are in the haynes.

ten minute job..

Post by **ermie571** » 08 Dec 2011, 07:47

Kev - that's great info....

but to the original poster....my wiring is brown to the oil pressure switch. It has the vw plastic connector to join it to the loom, so not sure if something has been replaced somewhere along the line.

regards

Em
xx

Post by **edoh** » 08 Dec 2011, 08:57

mine only has wiring to one switch (the one between the push rods) -

connected to a green wire?!?

just unplugs with a click -
then a deep socket (24mm?) - to get at the switch -
right torque (in haynes) important -
the previous sender i took off -

non descript grey/black -
pretty sure i replaced with a blue sender switch -
kev - is this the low oil sender switch - the one between the push rods? n have i used the right colour switch?
blinks on ignition - then goes out -
err... comes on occassionally - when van pulls up at lights/roundabouts - goes off instantly on slight revving.....

Post by **medenview** » 08 Dec 2011, 10:47

Thanks for all the info.

I don't get any oil light whe switching the ignition
on

Simon

Post by **ermie571** » 08 Dec 2011, 11:59

yep - thats the switch I replaced

blue should be the replacement I was informed.

if it comes on breifly when running you have experience a moment of low oil pressure...

poss wrong grade oil...if it happens alot try a thicker oil

but make sure its mineral and not semi synthetic

poss low oil...keep an eye on levels

idle to low for the really cold times (i noticed that my camper flickered on idle on particularly cold days last winter)

sommat not very pleasant happening in the engine!

I find my light comes on with ignition, and stays on til running when engine cold, but if engine warm, it may go off virtually instantaneously....

Em
xx

Post by **Ian Hulley** » 08 Dec 2011, 11:59

ermie571 wrote: but to the original poster....my wiring is brown to the oil pressure switch. It has the vw plastic connector to join it to the loom, so not sure if something has been replaced somewhere along the line.

On the late twin sensor system BOTH wires are brown from a junction near the thermostat housing on the front nearside of the engine bay to both oil pressure sensors.

Rich Tea wrote: Most I believe have two oil pressure sensors, one by the left hand bank of cyliners and one hidden down behind the crankshaft pulley on the water pump side. I think early models have only one.

Is correct.

If the wire to the sensor between the pushrod tubes is earthed the light will stay on. If the wire to the sensor near the oil pump is earthed out the 'buzzer of doom' doesn't work, if the wire comes off this sensor the buzzer comes on as soon as the engine reaches 2,000rpm (this is why the 90 degree terminal on the end of the wire is cable tied to the sensor).

Ian

Post by **kevtherev** » 08 Dec 2011, 13:29

edoh wrote:kev - is this the low oil sender switch - the one between the push rods? n have i used the right colour switch?
blinks on ignition - then goes out -
..

...is correct
It's not just a low oil sender it's a low pressure switch and will light up the warning lamp

low pressure (below 0.3 bar) is attributed to
Oil pump failure (buzzer sounds aswell if fitted (late))
Tick over to slow
Poor quality oil
engine too hot
oil foaming due to low oil level in the sump
faulty or wrong switch fitted (Blue 0.3 bar single pin, normally on)

Good pressure will extinguish the lamp whilst the engine cranks

Post by **edoh** » 08 Dec 2011, 18:58

Oil pressure switch - Blue
Febi

Price per Unit (piece): £4.06 (inc. VAT)

i'm pretty sure my replacement is the blue one from brickwerks -
details below -
http://www.brickwerks.co.uk/index.php?p ... t&Itemid=3" onclick="window.open(this.href);return false;
--------------------------------------------------------------------------------
Oil pressure switch - general use
Normally closed, for normal oil light [blue wire]
Switching pressure - .25 bar [3.68 psi]
M10x1 thread
24mm head
6.3mm spade terminal

Replaces VW No. - 028 919 081 D
Weight = 0.05 kg

does this sound about right?

thanks for all the contributions people -
as always amazingly helpful -

Post by **kevtherev** » 08 Dec 2011, 19:05

Oil pressure switch - general use
Normally closed, for normal oil light [blue wire]
Switching pressure - .25 bar [3.68 psi]
M10x1 thread
24mm head
6.3mm spade terminal
Is this right?

kevtherev wrote:if it is the low pressure switch then it must be replaced with the blue 0.25 bar M10 X 1 (available from brickwerks) connected to a black/white wire

I think we have covered that

Post by **edoh** » 08 Dec 2011, 21:48

cheers matey

twice -
to make sure !

Post by **medenview** » 10 Dec 2011, 15:26

Hello all. Just got Campervan back and new "blue" oil pressure switch fitted but the mechanic couldn't find any cables that should be connected to it. I've had a look without success

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