Low Oil Pressure - Guidance please

[AndyBa]

Had another go trying to get the 2 x sump bolts installed. I tried some grease but that didn't hold it.
I invested in a magnet and by using a bit of mains electrrical wire I was able to fish them out when they went AWOL.

I've just been reminding myself about how to magnetise metal so my next attempt will be with a magnetised hex ball end. What a pita this is.

[SRAutoSolutions]

aye they bolts are a bit of a pain in the arse. Wobbly 1/4 drive extensions are your friend.

Ive replaced a few oil pumps on these engines, if caught early enough it will live a good while yet although any time you see shimmer you should having a peek at the bearings.

[AndyBa]

So the last two bolts are in. I'm hoping there are no minor leaks from the sump but time will tell!

So where do I look next?
The gauge I have connected in place of the sensor is still reporting low oil pressure so that would seem to indicate the pressure sensor is OK - correct? If so that would mean the wiring is good too.

I've read some on-line articles and the next suggested step is to check for crud near the sensor....tbh I thought that would be the second after verifying with a manual gauge.
If only it was less intrusive/require replacement bolts to take the rocker cover off. Not the 15min job it would be on my MK2 Golf GTI!

I'd be surprised if it was a build-up of dirt. The bottom end looked very clean. So then the next culprit could be the cam bearings which are another PITA job which is a little beyond what I'm willing to do.
Am I missing any other possible cause?/simple fix?

Thanks in advance.

[SRAutoSolutions]

The process i follow when anything comes in like this.

1/ check oil level/condition. check oil filter condition. visually check anywhere with oil pressure for leaks (including turbo)
2/ check of the sensor itself, including wiring. these can be tested off the car with air pressure.
3/ pressure gauge into the sensor hole and crank from cold. should be >2bar
3/ remove sump and check/clean pick up pipe, check the drive wheel for damaged teeth, use the airline to blow through the oil galleries.
4/ if the above looks clear then i'd be happy enough to fit a new pump at this time ( for what they cost against having to remove the sump again
5/ if there are still issues then it's strip down time.

I push this all the time on forums and forever get grief from it but test everything before throwing parts at problems. Testing components is free, and the internet will tell you how to test anything you need to. Only when you can prove (beyond reasonable doubt) that something is the cause should you spend money,

[AndyBa]

The process i follow when anything comes in like this.

1/ check oil level/condition. DONE & REPLACED
check oil filter condition REPLACED
visually check anywhere with oil pressure for leaks (including turbo) MINOR OIL DRIP FROM ABOVE THE GEARBOX BRACE
2/ check of the sensor itself, including wiring. these can be tested off the car with air pressure. IF A MANUAL GAUGE SAYS LOW (1 to 1.5 bar SURELY THEY ARE WORKING?
3/ pressure gauge into the sensor hole and crank from cold. should be >2bar
3/ remove sump and check/clean pick up pipe DONE
check the drive wheel for damaged teeth DONE
use the airline to blow through the oil galleries. NOT DONE ARRRGH!
4/ if the above looks clear then i'd be happy enough to fit a new pump at this time ( for what they cost against having to remove the sump again IT IS RECENT AND CHECKED AS IS THE DRIVE BELT
5/ if there are still issues then it's strip down time.

I push this all the time on forums and forever get grief from it but test everything before throwing parts at problems. Testing components is free, and the internet will tell you how to test anything you need to. Only when you can prove (beyond reasonable doubt) that something is the cause should you spend money,

Many thanks for your prompt reply. Responses in CAPs above.....not shouting
I slid under the van today and noted various new parts. EGR/turbo possibly recent, looks very clean. Module on the right side of the cylinder head (looking from the front).
A drip of oil from what appears to be fine bore pipes onto the gearbox/subframe brace. I can't identify them in my Haynes.

[SRAutoSolutions]

no worries, it makes it easy to understand which parts you are replying to.

Normally i would trust a mechanical gauge, but i use my gauges pretty often and after a few years of putting engines back together it gets easier to tell when something doesnt look right. Everything you have said you have done or checked should be giving good pressure unless there is a serious internal issue.

To find this you'll need to start removing some components. i'd be looking to get the rocker cover off, filter out, sump and oil pump off and blow through the pick up hole. Ideally you'll hear a pop and something will fire out of the filter housing (this also has a small risk of jamming any blockage further up - but at this point id be taking the chance). Get a look at the filter housing when its off and look for any pressure relief valves - a worn spring can cause a drop.

worn journals/bearing can give lower pressure but normally go hand in hand with other issues.

From memory i had a skoda taxi in a while back with intermittent low pressure faults and it turned out to be a part of the loom at the fron of the engine that was bent round a metal bracket and had been chaffing, again worth a wee check just to rule it out.

[AndyBa]

Thanks again.
I now know that the minor drip is from me connecting the gauge to the sensor outlet. There is no seal on the 90deg adapter I installed!
EDIT. just had a closer look at the oil pressure sensor which has the VAG markings, part no and 09 20 stamped on it.

So it sounds like I made a mistake before refitting the sump by not checking for an issue with the feed to the oil filter from the pump to rule that out. I thought the oil fed through the crank and upwards, but what do I know!

The pressure relief valve is built into the oil pump and that (pump) has been swapped. There is no relief valve near the filter (that looks to be on 1.9TDIs not 1.6TDIs)

[AndyBa]

Had a ponder over this....
I didn't fancy taking the sump off again so I thought I'd do something a bit random.
Bearing in mind the oil goes through the filter I thought I'd test the pressure there.
I drilled a hole in the top of the oil filter cap and tapped it so one of the oil pressure gauge attatchments would fit. Rigged-up the gauge and it is reading about 4 bar on tick-over. So plenty of pressure there! So the issue is upward of the filter.

edit....I did take the cap off and remove all the swarf before I re-installed btw!

I did buy a cheap "spare" oil filter cap off ebay to use for this test but annoyingly that didn't fit so I modded the one on the van...Now to get a replacement!!!!
£29 at the dealers but that helped isolate the fault a bit more.

I'm thinking it will be an issue with the head/cam bearings. That looks an awful job.

[SRAutoSolutions]

its a bit unusual if you get 4bar in the filter housing but low pressure from the pressure switch. was the oil light on while you were testing it?

i dont know if ive been thinking about it too much and started mixing myseld up but there was something i read before about these engines having a variable oil pressure when it reached a certain rev range. For the life of me i cant remember exactly what the story was with that because i found the issue before that (look rubbing off a bracket) but maybe worth checking.

Its rare (at least in my experience) for cam journals to give that much of a drop without showing other problem too.

Any signs of oil contamination in the coolant?

[AndyBa]

There are no signs of the coolant being contaminated with oil nor mayonaise on the oil filler cap.
The engine doesn't make an excessive noise or smoke at all.

[SRAutoSolutions]

From here i dont think theres much else i could recommend without actually seeing the van mate.

Please let me know if you get any progress or feel free to message if theres anything else you think i could help with.

Good luck.

[AndyBa]

Thanks.
I gave up and took it to a garage!
The guy did some further testing.
The readings he got was 0.5 bar at idle and 1.4 bar at 2000rpm so slightly low. Took the van for a road test and found the pressure was still "slightly low" but not horrendously so. He checked the wiring and it looks like the sensor wire is shorting. He did say the wiring needs a good clean and to be tie-wrapped properly so that is the next task
Interesting that the oil pressure switch is marked 0.3 to 0.6 bar. So when the wiring is fully sorted I'd be non the wiser.
He also found the gearbox earth disconnected. That explains why we couldn't get it started when we first got it. Some has been playing around before me!
Going to start using it and see how it goes.

[SRAutoSolutions]

Glad you got it sorted.

[Wrightshot]

How are you getting on with this? Was it the wiring fault?
I have a similar problem with mine at the moment

[AndyBa]

So far I haven't found the dodgy wiring and the low oil pressure light still comes on randomly but not constantly! I've handed it over to my son to use.
I should do your own checks starting with a manual oil pressure gauge. We bought the van with no history and it is only through dismantling part of it that I have learned a bit more. New oil pump, reground crank, new main and big end bearings. turbo. I wish I'd removed the cam cover too but I do repairs on the drive and the weather is rubbish!