How to access the oil pressure sender?

[AudiC]

Hey, I'm trying to access the oil pressure sender to check my pressure, and have ran into a fairly major issue. I'm assuming (with my very little knowledge) that it is located close to the oil filter which seems seems to be embedded quite literally as deep in the engine bay as humanly possible. I've attached images to try and understand if I am in even vaguely the right place, I believe I should be aiming for the small white writing which (I think) Is the oil filter? Are there any tricks which people have used before to make this an easier process?

Thanks - Connor

Audi A4 B6
2003
2.0L FSI Estate

 

[Manics]

Went through all of this recently. It's a good idea to keep an eye on your oil pressure given the sludge issues on various engines.

Firstly, there is no sender to access. There is only a switch attached to the oil filter housing which detects above 25PSI, under that and it throws the OIL warning on your DIS. This is why you cannot monitor oil pressure in VCDS -there is no data to monitor. So if you want to monitor oil pressure you need either a mechanical gauge, or an electronic gauge with a sender.

The black thing with the white writing on it, is indeed your oil filter. Where it screws into is the oil filter housing -it's here that you want to pay attention. Check this out: https://www.audi-sport.net/xf/threads/how-screwed-am-i.378849/#post-3318057

Now I can tell you from experience that you are wasting your time trying to use that test port on top of the filter housing. You won't ever get the plug out, and you have to waste money on adapters to try and create space to screw in the sender. Instead you want to remove the plug with the wires going into it (in that link highlighted red rectangle) which is facing the firewall (the wall between the engine and the cars cabin). That's the plug with the oil pressure switch in it.

Plug your tester into that instead -5 minutes to swap. You'll get the oil warning whilst you do this as the switch will detect no oil pressure. You can test, then remove and reinstall the standard switch.

Another link that will help make sense of it all: https://www.audizine.com/forum/show...essure-Survival-Guide-and-troubleshooting-DIY

Let me know if you're installing a gauge permanently into the car (this is what I did) and I'll give you some more tips.

 

[AudiC]

Went through all of this recently. It's a good idea to keep an eye on your oil pressure given the sludge issues on various engines.

Firstly, there is no sender to access. There is only a switch attached to the oil filter housing which detects above 25PSI, under that and it throws the OIL warning on your DIS. This is why you cannot monitor oil pressure in VCDS -there is no data to monitor. So if you want to monitor oil pressure you need either a mechanical gauge, or an electronic gauge with a sender.

The black thing with the white writing on it, is indeed your oil filter. Where it screws into is the oil filter housing -it's here that you want to pay attention. Check this out: https://www.audi-sport.net/xf/threads/how-screwed-am-i.378849/#post-3318057

Now I can tell you from experience that you are wasting your time trying to use that test port on top of the filter housing. You won't ever get the plug out, and you have to waste money on adapters to try and create space to screw in the sender. Instead you want to remove the plug with the wires going into it (in that link highlighted red rectangle) which is facing the firewall (the wall between the engine and the cars cabin). That's the plug with the oil pressure switch in it.

Plug your tester into that instead -5 minutes to swap. You'll get the oil warning whilst you do this as the switch will detect no oil pressure. You can test, then remove and reinstall the standard switch.

Another link that will help make sense of it all: https://www.audizine.com/forum/show...essure-Survival-Guide-and-troubleshooting-DIY

Let me know if you're installing a gauge permanently into the car (this is what I did) and I'll give you some more tips.

I can't say how thankful I am for that response, it quite literally solved 90% of my problems. the reason I am doing this is because my dash is giving me an oil pressure warning light. I was told to firstly change the filter and oil + flush the oil system to get rid of as much sludge as possible. Then I am going to test the pressure after that, because I received this car not knowing quite how long ago the oil could have been changed.

My number one question is, accessing the oil filter housing seems to be borderline impossible? I have got underneath the car and can just about reach the end of the oil filter but not much else. Any idea how you're meant to tackle this job properly from an access point of view?

Once again, brilliant response, thank you - Connor

 

[Manics]

Hey -glad to hear that, Connor.

I did mine from above. You just need to get a wrench on that switch which bolts in to the filter housing (number 17 in your diagram). If you remove the coolant reservoir out of the way (only when the engine is cold) you'll see far more clearly and have the room to work. That of course is the white tank at the top right of your engine bay. Doing that is as easy as it looks. Unscrew that one phillips screw, then just angle it up toward the windscreen and lift and out of the way. The hoses will stay connected. Put it to one side on the engine somewhere.

Work your way up from the filter, then you can get a wrench side-on to that 17 switch bolt -from your orientation where the coolant reservoir was. Remember, it's at the back of the housing. Doesn't take much at all.

If installing permanently, the easiest way is to get one of these:
https://www.ebay.co.uk/itm/M10-x-1m...ote-Adaptor-/283174306493?hash=item41ee8102bd

That listing has ended, but shows what you need. M10 is the correct size. You screw one end into the filter housing where that switch bolt 17 was, then that gives you two ports at the other end of the adaptor. You screw your oil pressure sender into one (so giving pressure data to send to your electronic gauge) and you screw your number 17 switch bolt into the other (to keep your car DIS happy. The switch will still register +25 PSI).

The length of that adaptor means you have plenty of room to play with. Top tip: tightly wind PTFE tape (like plumbers use) around the threads of all of your male connections to reduce the chance of leaks.

Then you'll need to run a ground to your sender, and a cable down through your ECU box into the cabin to the gauge. Remove your ECU cover, make sure your cabin puddle lights are on and you'll see down into the car. I put my gauge in the small change tray at around 4pm to the steering wheel, just by the driver's right knee. It keeps the dash looking OEM and reads well down in the corner. Also, you can piggy back a live (which your gauge will need) in the fuse box which is just behind the side panel of the dash with the drivers door open. If you install the gauge where I did then that live is super simple to run since they're right next to each other.

Piggy back a live using this (which plugs into your fuse box):
https://www.ebay.co.uk/itm/2x-Add-A...ATC-12v-24v-/152026075087?hash=item236575cfcf

I used this gauge so matching the red interior OEM:
https://www.ebay.co.uk/itm/2-Inches...or-Auto-Car-/273145631140?hash=item3f98bf91a4


I like having a oil pressure gauge. More peace of mind. However if you have a serious sludge problem this of course will not cure it in any way. Just help you to see what's coming before the OIL warning comes up on your DIS. You got lucky if you saw that warning and the car is still going. For many they see that warning and 20 seconds later it's BANG.

Hopefully your oil change is the last you hear of it.