oil pressure sensor / sender replace or measure pressure

[cullenvb]

has anyone replaced the one-wire pressure sender located forward of the oil filter on the passenger side of the engine block? if so, was it done without removing the engine? i'm talking, obviously, only about the c5 rs6 as other audis i'm sure don't suffer from this messed-up design locale.

i'm suffering from low oil pressure warnings after the car's fully warmed up and i slow to idle speed. after three beeps and the red icon, the alert goes away. i've changed the oil (5w40), replaced the oil filter, swapped out the oil pump and cleaned the pickup tube.

i can't figure out a way to get a pressure gauge onto the oil cooler (again, location), so i can't conclude for sure i'm suffering from true low pressure when oil's hot. if there's a way to do that, i'm all ears. my only guess is to remove the subframe bolts on the passenger side and take out the engine mount. is that the way to go?

car has 115,000 miles but has always been well maintained. i put in a new turbo and rebuilt the other - no major oil collection within the air pipes. it doesn't burn oil and leaks only from the rear main seal (another joy).

i understand it's possible i have worn crank bearings, i just want to tackle this from easiest to hardest.

p.s. could stuck open oil check valves possibly be a cause? i suspect not, but again i'm running out of theories.

cheers

[Shoppinit]

Sender switch is the most likely culprit. If you can replace it without too much faff and the problem goes away then that will confirm. I understand the desire to put a pressure gauge on there, though, but if there isn't enough room...

[Jayjay101]

you can get it off but its a bit of a pain and have be care full you don't crush the washer that go's in to the block as it will leak oil.you can get a kit from 42 draft designs for just under £50 that replaces the sensor with a take off pipe and a block so you can fit a gauge.there on awesome gti's website

[Shoppinit]

^good info.

[Mɐʇʇ]

Interested if you managed to do this. I couldn't without removing at least the lock carrier - any pics?

you can get it off but its a bit of a pain and have be care full you don't crush the washer that go's in to the block as it will leak oil.you can get a kit from 42 draft designs for just under £50 that replaces the sensor with a take off pipe and a block so you can fit a gauge.there on awesome gti's website

[cullenvb]

Interested if you managed to do this. I couldn't without removing at least the lock carrier - any pics?

you can get it off but its a bit of a pain and have be care full you don't crush the washer that go's in to the block as it will leak oil.you can get a kit from 42 draft designs for just under £50 that replaces the sensor with a take off pipe and a block so you can fit a gauge.there on awesome gti's website

thanks for all the feedback. just to be clear, we have one person who successfully changed the sender unit by removing the front lock carrier (at least). has anyone removed the sender by any other means? i was about to remove the engine mount to gain access but i won't if i'm told it can't be done that way. thanks.

[cullenvb]

just a follow up - thanks again for the insight. I re-installed the passenger aux. radiator this week. i'm going to see if that eliminates the pressure warnings before proceeding. i had it removed as the european version of the rs6 didn't include either of the two radiatiors. i live in a similar climate to germany. however, this car is chipped. i believe the extra power generates higher temps. in 2004 audi made an rs6+ which included the two coolers for that version's higher power. so in hindisght i should've never removed it, however, in my defense, the chipped ecu hadn't ever worked properly until it was recently repaired (a story for another day). my initial thinking was removing the cooler would eliminate heat soak concerns and provide better air cooling for the intercoolers.

i now know the coolant temp. guage is really a 'dumb' guage that will just settle in the middle unless there's wildly different readings. i had thought the removal of the radiator made no impact b/c the guage never deviated from the old readings. only thru VCDS did i get a true real-time reading.

preliminarly speaking, the oil temp does appear to be lower vis-a-vis similar condions before the radiator reinstall. of course now i have to take into account the falling temps outside...

typical rs6 - it was easier for me to replace the oil pump, change the oil, change filter and replace the coolant radiator than remove/replace the oil sender.