Golf Mk6 CAYD 1.6 TDi Bluemotion Oil Pressure Light flashing

[maddogphysics]

Had the car since just before Christmas 2022.
87,000 miles on the clock.
2011 registration.

Noticed a puddle of oil on the driveway a couple of weeks ago.
No lights on the dash and VCDS was clear.
Engine sounded fine.

After searching for the source, initially thought it was the turbo, but soon saw oil coming out of the oil pressure sensor at the back of the engine, near the top. Pouring out.

Purchased an OEM replacement and noticed that the wiring from the old pressure sensor was cut, the other end of the cut wire underneath a jubilee clip on one of the air intake hoses.
After fitting, and checking the oil level, which had never gone below the minimum anyway as I check every weekend, I started the engine.
Within 20 seconds or so, the oil lamp stated to flash, about 3 times, then go out for about 30 seconds and then start to flash again. This kept going until I switched off the engine.

There are NO warning beeps either.

Couldn't see any more leaks but I was concerned that maybe some damage had been done before I noticed the oil spill.

Off with the sump to inspect the bottom end of the engine.

Absolutely clean, no bits of metal anywhere, no signs of overheating or scorching.
Plastic baffle in place and untouched.
Took off the oil pump and pick-up pipe.

Pick-up pipe was dirty with bits of sealant in it and such. In fact the original sealant was overspilling into the sump and must have gone broken off into the filter over the last few years.

Pick up pipe is now clean, oil pump back on but do I need to do anymore checks whilst the sump is off?

Do you think the oil cooler needs checking?
The temp of the oil never really went above 90 degrees (MFD) anyway but I have noticed the engine coolant temperature doesn't reach 90 either...it varies quite a bit and is not stable (new thermostat?)

Thanks for taking the time to read.

[Crasher]

What is the VIN and the part number of the switch you fitted?

[maddogphysics]

I am thinking of finding out the actual oil pressure mechanically once the sump is back on.
Will give me a chance to take off the oil pressure sensor and find its part number...I really cant see the numbers, my eyesight is so poor now, sadly.

The vin of the car is: WVWZZS1KZBW328017

The varient is: ACCAYCX0 not the CAYD that I mistakenly thought it was.

Crasher, you actually fixed my Passat B6 almost 10 years ago...after the injectors were replaced under warranty by VW in Chesterfield, the VW technicians had replaced the vacuum pipes the wrong way around so the turbo stopped working!
You spotted that quite quickly. Thanks.

[Crasher]

WVWZZZ1KZBW328017.

A CAYC engine, the switch should be part number 036 919 081 D which is 0,3-0,6BAR and colour coded green. The VW specification is bizarre, they state

"Oil pressure when idling: at least 0.6 bar. increase speed. At 2000 rpm and an oil temperature of 80 °C, the excess oil pressure should be at least 1.0 bar"

The specification I am used to is 2 Bar at 2000rpm as a minimum and preferably 3 Bar.

[maddogphysics]

I eventually took the oil cooler off.

The oil side was blocked but with a bit of dish washer tablets, boiling water and lots of agitation, it finally cleared.
The coolant side looked like it had rusted, but aluminium doesn't rust so I don't know what it is.
Anyway, all cleaned and I'll start putting it back together over the weekend.
I will do a pressure test in VCDS and with a proper pressure testing kit...see how they match up.

I will keep you all informed.

[Crasher]

G13 coolant when it breaks down looks like rust.

[mickeybo]

Ask yourself the 64 dollar question whats the first fall off point in the oil pressure system

[maddogphysics]

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Ask yourself the 64 dollar question whats the first fall off point in the oil pressure system

I did, many times.

Well, at least the EGR valve was cleaned.
The coolant system was flushed.
The oil pressure sensor and harness replaced.
Whilst waiting for the sumps silicon gasket to go off, took the time to re-seat the parking sensors...took the bumper off to remove a dead and bleached bumblebee inside one of the headlights and noticed two parking sensor fittings were broken.
The oil cooler replaced (I think this was the cause all along and maybe damaged the oil pump).
New oil pump fitted.
Still waiting to put it all back together but will delay a bit to watch Six Nations.