Oil Pressure Gauges

[zrickety]

I'm curious who is running a gauge and what kind of warm readings you're getting??
Surely some of you track guys like @jay745 are running one (but not Jay lol).
I recently installed a mechanical gauge, but only because I was getting random low oil pressure readings (not hard right turn related).
This is after basically a water pump failure, and an aftermarket balance shaft replacement.
The spec is for 2000 rpm, and I'm seeing 38-39 psi when the car is up to temp. This is borderline.
If my gauge is to believed, it's 10 psi at idle. Ruled out the pressure switch (set for 17 psi).

Looking for more data from the community! What kind of numbers are you seeing?
And has anyone had an oil pump failure? I've only found one old post with info and he did bottom end bearings.
Edit- Bentley manual page

Mine was constantly coming on and off only in low speed stop and go traffic after being really hot, never at cruise. I would get it about once every other day, usually on my 30 mile commute home from work when I'd get caught in traffic. I changed the rod and crank bearings 3000 miles ago and it hasn't come back since.

From what I read, the pressure sensor checks to see if its closed at 2k RPM and will turn the light on if it happens multiple times in a short time (like 3 times is a second or something). If you're on the edge of the necessary pressure, that's why it comes on in stop and go situations. Spec is 2.7-4.5 bar at 2k RPM with the oil at 80 degree C.

Before changing those bearings I was seeing ~2.1bar at 2k RPM. After I see 1 bar at hot idle, 2.7 on the dot at 2k, and 3bar+ while cruising, up to ~4bar in high RPM's.

 

[Roadrunner_GTI]

I don't know how I missed this thread but I definitely think we need more oil pressure data points to baseline what's normal vs not. Keep in mind that oil temp is a huge factor in oil pressure as well, so it's worth logging temps vs pressure. The ECU will throw a low oil pressure light if the oil pressure switch isn't closed at 2000 rpms (below that the ecu isn't monitoring the oil pressure switch, and you can actually unplug it under 2k rpms to confirm that). Like you mentioned, the oil pressure switch will close between 17-23 psi. The spec is the following:

That said, at hot 750rpm idle (200* F) my oil pressure is around 16-18psi, depending on ambient temps. At lower oil temps (170-185* F) the oil pressure will be slightly higher at around 20psi. At 2000 rpms the oil pressure is usually around 33-35psi, depending on exact oil temps. Again slightly higher if the oil temps are below 180* F. At 3000 rpms the oil pressure is about 40psi, and tops out around 46 psi at full rpm. I rarely if ever see higher than upper 40s oil pressure. Keep in mind this is with Motul X-Cess 8100 5w-40, but have often considered switching to Motul Sport Ester 5w-50, which is more appropriate if the car sees track use. The higher viscosity would help stabilize oil pressures at higher temperatures seen on track (230*F+).

 

[zrickety]

I don't know how I missed this thread but I definitely think we need more oil pressure data points to baseline what's normal vs not. Keep in mind that oil temp is a huge factor in oil pressure as well, so it's worth logging temps vs pressure. The ECU will throw a low oil pressure light if the oil pressure switch isn't closed at 2000 rpms (below that the ecu isn't monitoring the oil pressure switch, and you can actually unplug it under 2k rpms to confirm that). Like you mentioned, the oil pressure switch will close between 17-23 psi. The spec is the following:
View attachment 275761

That said, at hot 750rpm idle (200* F) my oil pressure is around 16-18psi, depending on ambient temps. At lower oil temps (170-185* F) the oil pressure will be slightly higher at around 20psi. At 2000 rpms the oil pressure is usually around 33-35psi, depending on exact oil temps. Again slightly higher if the oil temps are below 180* F. At 3000 rpms the oil pressure is about 40psi, and tops out around 46 psi at full rpm. I rarely if ever see higher than upper 40s oil pressure. Keep in mind this is with Motul X-Cess 8100 5w-40, but have often considered switching to Motul Sport Ester 5w-50, which is more appropriate if the car sees track use. The higher viscosity would help stabilize oil pressures at higher temperatures seen on track (230*F+).

This is great info, thanks.

 

[erictrain76]

GM to the group, I know thread is old but I'm also looking for low oil pressure at hot idle..I have a 2012 gti mk6 and I'm getting roughly 40psi at 2k and I'm at 10-7psi at idle.. New rebuilt, changed out everything oil related along with new bearings /pistons/connecting rods. Oil Pump oem/cleaned pickup screen/oil drain valve/balance shafts oem/timing set/check valve under the head/new o-rings around the turbo, no oil leaks/oil cooler/vacuum pump/cam bridge and I popped the screen out first thing/control vvt valve/ New oil switch oem..
Using quality oil Guage (OTC) after 500mile breakin Castro 5w40

 

[erictrain76]

I never hear anyone say anything about the oil jet sprayers, could they be a corporate in some of these Mysteries

 

[erictrain76]

They are little check valves and if no one ever check them they could be clogged or not holding pressure

 

[Roadrunner_GTI]

GM to the group, I know thread is old but I'm also looking for low oil pressure at hot idle..I have a 2012 gti mk6 and I'm getting roughly 40psi at 2k and I'm at 10-7psi at idle.. New rebuilt, changed out everything oil related along with new bearings /pistons/connecting rods. Oil Pump oem/cleaned pickup screen/oil drain valve/balance shafts oem/timing set/check valve under the head/new o-rings around the turbo, no oil leaks/oil cooler/vacuum pump/cam bridge and I popped the screen out first thing/control vvt valve/ New oil switch oem..
Using quality oil Guage (OTC) after 500mile breakin Castro 5w40

If you're getting 40psi at hot 2k rpm, then I'm not sure why you'd be experiencing low oil pressure at idle. The oil pump is a two stage setup, with the second stage engaging around 1500 rpm. So if below that you're experiencing low oil pressure, but above that you arent, then that tells me you have a defective oil pump. As far as the oil squirters, you're correct in that they are essenstially a spring loaded valve but I've rarely seen these fail. And when they do, I would expect low oil pressure across the entire rpm band.

 

[erictrain76]

Thanks for that info, the oil pump was replaced from an aftermarket pump.. Went from a rockauto pump to a vw /audi pump.. At hot 2k it's really 38psi if you sturdy the rpms around 2k