Oil pressure senders on 2.1L engine
(The 1.9 use only one sender, between pusrods, left side, same location of 2.1L but not the same BAR, it's the blue one)

 

 

(Click on image for a bigger view and more information.)

View of the .9 BAR location and wiring & information

View of the .3 (.25) BAR location & information

This is another picture sent to me by Ken Lewis, you can see it in the red circle.

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This one is from William Polowniak from the The Vanagon Mailing List Server, you will see that the sender angle looks different but the location is the same.
 

Color code for the sender

  • Brown (i have seen a blue one) .3 bar 081 C (side of case / low pressure)

  • Grey or Black .9 bar 081 A (back of case / high pressure)

  • Blue .25 Bar ? (new spec from VW) (side of case / low pressure), the blue one is also use on the 1.9

Oil pressure sander/switch anatomy. (explanation) (and the “Idiot oil light pressure problem)

There's also a good writeup on how oil pressure work, why they go ON and gauge installation on van-cafe's site:
http://volkscafe.com/vanagonparts.jsp?pa=ip&ip=1401786957

Why does the light go out at 2000 RPM?

While there is a "high" pressure switch and a "low" pressure switch, they both cause warnings when the oil pressure drops too LOW. Since "too low" is a bit of a subjective thing in an engine, VW decided to implement two standards. The higher the engine RPM, the higher the oil pressure should be. If you have just one oil pressure switch with a set point low enough (say 4.4PSI, 0.3 bar) to not engage at idle, that leaves way too much slack for when the engine is at high RPMs when the engine should have at least 13.2 PSI (0.9 bar / replacement part by VW is 0.75-1.05 BAR, see  picture at left) . The "low" pressure switch is used to alert the driver if the oils pressure dips too LOW while the engine is running at less than 2000 RPM and the "high" pressure switch is used to alert the driver if the oils pressure dips too LOW while the engine is running at more than 2000 RPM.

More specifically it works like this:

The dynamic oil pressure monitoring system gets inputs from two pressure switches. One switch is closed with no oil pressure and opens when oil pressure rises to about 0.3 bar, called the .3 bar switch. The .3 bar switch is located between the left (driver's side) two cylinders (pushrods). The other switch is open with no oil pressure and closes when oil pressure rises to about 0.9 bar, thus called the .9 bar switch. The .9 bar switch is located below the water pump & crank pulley, near the oil pump.
(I just found this one location today with the help of William Polowniak photo’s  & other good member of the list)

The monitoring system seems to only "look at" the .3 (.25) bar switch below 2000 RPM and ignore the .9 bar switch. Above 2000 RPM the active switch is the .9 bar switch while the .3 bar switch is ignored. Below I've described a properly operating monitoring system. Note that I say "monitoring system" because some of the conditions describe an abnormally low oil pressure condition.

A. Ignition ON, engine NOT running -- or -- engine running at LESS than 2000RPM (.9 bar switch is ignored)


1. Low oil pressure exists (below .3 bar), keeping .3 bar switch closed

--Oil light: Flashes

--Buzzer: Silent


2. Normal oil pressure exists (above .3 bar), opening .3 bar switch

--Oil light: Off

--Buzzer: Silent


B. Engine running at MORE than 2000RPM (.3 bar switch is ignored)


1. Low oil pressure exists (below .9 bar), keeping .9 bar switch open

--Oil light: Flashes

--Buzzer: Sounds


2. Normal oil pressure exists (above .9 bar), closing .9 bar switch

--Oil light: Off

--Buzzer: Silent

WARNING ---WARNING ---WARNING ---WARNING

CHANGE BOTH SENDERS / SWITCH IF YOU DON’T KNOW THEIR HISTORY, READ THE FOLLOWING…(Scary!!!)


The .3 (now a .25 BAR is sold to replace the .3 to solve the “Idiot oil light warning problem”) bar oil pressure switch located between the 2 left cylinder pushrod should be change if your not sure about her history, it is located at the lower part of the engine so if it start leaking like mine did, your in deep trouble, I almost blown a engine because of that switch. I have lost more than half of the oil (in a 10 minute drive). The switch give no warning at all as she still had pressure!!!. I was lucky (it could have been a blown engine) that I work close to my home. (Major spill in my garage)


Be aware that this is a very serious problem, (oil is a must) and this part should be CHANGE before any major trip. It is a easy job to do, it take a 24mm socket head and an hour to change.

The .9 BAR is a lot more difficult to reach (take note that it seem that there is different location / angle for this one, probably years/generation related – see picture). It also takes a 24mm socket but the lack of space is the problem, the water pump pulley as to be removed. I use a mix of 24mm key/vice grip/24mm socket to remove this one.

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