[B767capt]

I have always wondered what oil pressure this S85 motor runs. I got to looking around and there is a oil pressure switch on top of the oil filter housing. I took it out first to measure the threads and to see if there was room in that area for an adapter. There is plenty of room and the threads are M12 x 1.5. It has easy access in front of the right fender skirt.

I then started to look around for a good quality gauge and other BMW forums seem to mention AEM as a good choice. I didn't want to clutter up the dash with aftermarket junk so I decided to mount this in the glove box. I am going to use this to track pressure over time as the rod bearings get mileage on them. Since my bearings are new, I decided to install this to see what the number are. Another thing I like about the AEM gauge is the digital number as it's easy to read from the drivers seat over a needle with small numbers. This also has a green led on the outside that moves around the dial with pressure. The AEM sender uses 3 wires, a pos, neg and a signal wire. What's nice about that is our oil filter housing on our cars is rubber mounted and many senders use the metal housing it's screwed into for ground. It may be a problem with our setup. You can buy senders with a floating ground which will alleviate that problem. I also decided to change the oil back to the maple syrup (LM 10W60) to get a base line for the 10W60 weight. When I started the car cold, the pressure went right to 95 psi. As the cold idle settled down, it moved to 90psi.

Once I got on the highway and the oil was at normal operating temperature, it bounced around from 75-79psi. At a hot idle it was a steady 31 psi and was surprised it was that low with the 10W60. I bet the M1 would be even less than that. Did a quick leak check when I got home and everything was dry.

Here is the fitting I found on ebay which has the M12 x 1.5 threads at both ends, male and female. The threaded hole on the side is 1/8 NPT which fits the oil pressure sender. This wasn't easy to find.


Fold the front plastic liner back to gain access.


Here is the oem pressure switch screwed into the oil filter housing.


A 24mm box end to remove the switch.


Here is the fitting with the oem switch and the oil pressure sender.


Installed on the top of the filter housing.


A few hose that were initially in the way reattached.


90 psi after the high idle was back down to 700 rpm.


Oil temp almost 210 and here is the hot idle. It looks like 37 but it's 31psi. The flash of the camera caused it to look like 37. I sure wish this number was higher and bet it's in the 20's with M1.

 

[PRM5]

Been wanting to do this, your solution is great. I also want a fuel pressure guage inside the cabin.

 

[B767capt]

Been wanting to do this, your solution is great. I also want a fuel pressure guage inside the cabin.

Fuel pressure is the other gauge I installed after Jim had his stuck injector. Mine is under the hood for several reasons. One is if in the cabin, it will turn off when you shut the car off as it will be electric. Obviously you don't want a mechanical direct pressure in the cabin. I always pop my hood and hook a Cteck charger up so I can read that direct mechanical gauge under the hood for hours since no power is required. This way I can check leak down with no power on the car. It will stay up to 80 psi for 6 hours or so. Stuck injector and it drop to 0 quickly.

 

[SuckaGDog]

How much did the fitting and the gauge run you? Got a link to both?

Would running the 0W-40 be even worse then since the oil pressure is already low with the 10W-60 at full operating temp?

Thanks for posting this! Looking to add one also.

 

[PRM5]

I think this is the Gauge AEM 30-4407 now all we need is a link for the fitting

 

[SilberGrauE60]

Brilliant!

 

[B767capt]

I think this is the Gauge AEM 30-4407 now all we need is a link for the fitting

Correct on the gauge. I got the 150 psi one over the 100 psi as one vendor said they are more accurate when your psi is in the middle range. Amazon had the best price on the gauge, just over 180. Ordered it Friday and was on my door step Saturday with prime.

M12x1 5 M12 1 5 1 8 NPT Oil Fitting Pressure Tee T Adaptor Mercedes Diesel Turbo | eBay

Who's going to get the last one? There is a vendor in GB that has the same thing. I'll find that and post it.

 

[B767capt]

BMW 3 Series E30 E36 318IS 320 325i 328 M3 M12 Oil Pressure Gauge Adaptor MLR If | eBay

Here is the other one I found. You may want to check with them and make sure the threads are 1.5 not 1.0 fine threads. It says for BMW so it's probably 1.5.

 

[jcolley]

OT, but for fuel pressure, connect a pressure transducer with a bistable alarm that sounds if pressure drops within 90 seconds of power off. Stuck injector alarm.

 

[B767capt]

How much did the fitting and the gauge run you? Got a link to both?

Would running the 0W-40 be even worse then since the oil pressure is already low with the 10W-60 at full operating temp?

Thanks for posting this! Looking to add one also.

I don't know what pressure even lower than 31 would do but I bet M1 0w40 would be in the mid 20's. It was cool here today so I bet in the summer the oil would get a bit hotter. The iron count was up in my BS report on M1. I'll redo my bearings at 100k anyway just to see what they look like. I'll compare the oil pressure too at that time and see if there is a difference from today's psi.

 

[Fiftytwoeighty]

I've been tempted to add one of these for water temp and oil pressure. It's a little gimmicky, but the install appears OEM-ish.

P3Cars Vent Integrated Data Display and Boost Gauge - E60 5 series 2008-2010 - Turner Motorsport

Every ///M car I've owned had the water temp. They took that (water temp) and the dispstick away from us with the e60!

 

[B767capt]

I've been tempted to add one of these for water temp and oil pressure. It's a little gimmicky, but the install appears OEM-ish.

P3Cars Vent Integrated Data Display and Boost Gauge - E60 5 series 2008-2010 - Turner Motorsport

Every ///M car I've owned had the water temp. They took that (water temp) and the dispstick away from us with the e60!

I looked at that and called the company to ask them if it read oil pressure. The answer was no as it reads the info from your obd connector and I guess the BMW DME doesn't give a number only low pressure. He said it will if you hook up a sensor and run it to the P3. I decided against it then. One thing with the AEM gauges is it has a wire (which I didn't use) to hook a data logger up.

One other thing I forgot to mention in my original post is the wiring harness is only 6 feet and not long enough to reach the right front of our cars. I just cut the harness in the mddle and soldered in 3 foot sections to the 3 wires that go to the sender and use heat shrink around the whole length. It's also easier to feed the that wire harness through the fire wall with no plug on the end. I go in the SMG relay box and there is a hole there that goes into the back of the glove box. I ran my laser jammer wires through the same way.

 

[SuckaGDog]

I've been tempted to add one of these for water temp and oil pressure. It's a little gimmicky, but the install appears OEM-ish.

P3Cars Vent Integrated Data Display and Boost Gauge - E60 5 series 2008-2010 - Turner Motorsport

Every ///M car I've owned had the water temp. They took that (water temp) and the dispstick away from us with the e60!

The P3 gauge isn't worth it in our cars especially pre-lci since a few features are left out. If you compare a 08' P3 Gauge on Turner's site to an 06' one you'll see the difference in their feature chart on the product page.

The main thing that attracted me to them is the ability for air fuel ratio but that would only be available on LCI and only from AutoCouture since they have an agreement with P3 Gauges for that feature. Something to do with the OBD system.

 

[jcolley]

The P3 gauge isn't worth it in our cars especially pre-lci since a few features are left out. If you compare a 08' P3 Gauge on Turner's site to an 06' one you'll see the difference in their feature chart on the product page.

The main thing that attracted me to them is the ability for air fuel ratio but that would only be available on LCI and only from AutoCouture since they have an agreement with P3 Gauges for that feature. Something to do with the OBD system.

Most likely the 3/07 changeover from Dual K Line in the OBD port to D-CAN. More info directly available from D-CAN, but everything else is still there on the Dual K-Line, just a little harder to implement.

I can log AFR and whatever else from the DME using INPA/EDIABAS, Testo/EDIABAS, or BMWLogger. That shows you it's available from the port, they just didn't put any effort into developing it.

Someone clever could put together an Arduino like package with OBD comms to emulate the EDIABAS system calls and display on an LED.

 

[ASW338]

First, thank you to B7B6capt to provide very important details to all m5board members to install oil pressure gauge. Since our s85 must have minimum 1 bar (14.50 psi) to push the oil into crankshaft and bearings to separate metal to metal. I noticed when I used DIS to turn off the injector to start, my oil pressure gauge read 15 psi (min) to start. So, I experimenting lower grade engine oil to get more flow to lubricate engine parts when cold start. I changed to M1 0w20 2 days ago after 1100 miles used on 0w40. My gauge show 18 psi on 0w20 and 22 psi on 0w40 when hot idle. Both oil are above save range of 14.50 psi minimum. Lower viscosity will get more flow = more lubrication. If it drop to 15 psi from 18 over time, then I know there are something wrong with my bearings before too late. I don’t track my car and city driving only. It is very useful if we have oil pressure gauge in car to determine which viscosity to use to get maximum lubrication without affect the minimum pressure needs for our s85. Maybe I’m wrong.

 

[B767capt]

I tried M1 0W40 and my iron numbers spiked so I went back to 10w60. Will redo my rod bearings again at 100k and have no problem with that as it's easy to do. When I had a preoiler on the car, that low oil pressure switch would come on at 14.5 psi like you said. I didn't like driving around with the low oil pressure warning on so I took the system off as the car thought it had low pressure since the light triggered with the key on during the precharge. The DME saw oil pressure go up then down below the 14.5 limit and the warnings popped up. That's before I even started the car. Have to use ISTA/D to erase it. Let us know what the oil analysis is with the 20w. I agree flow is the most important aspect as it pulls heat out.

 

[neonguy]

this is a cool idea and I'm going to put one on my high-mileage beast. thanks for including pics!

 

[seif_ossama]

Thanks for the useful post, captain.

I just saw it today for the first time, I was able to find the fitting on ebay for $17 shipped, and will buy the AEM gauge as well, but can you please help me out with the hose/line that goes from the gauge to the fitting and how long it should be to go to the glovebox as I don't want to screw things up because it's not that easy to find these things here in Egypt so I will have to wait again if I bought the wrong hose, I'm trying to buy all the things needed now as the car is in winter storage.

Thanks
Seif

 

[B767capt]

Thanks for the useful post, captain.

I just saw it today for the first time, I was able to find the fitting on ebay for $17 shipped, and will buy the AEM gauge as well, but can you please help me out with the hose/line that goes from the gauge to the fitting and how long it should be to go to the glovebox as I don't want to screw things up because it's not that easy to find these things here in Egypt so I will have to wait again if I bought the wrong hose, I'm trying to buy all the things needed now as the car is in winter storage.

Thanks
Seif

Sure there are 2 AEM gauges, one at 0-100 psi and another 0-150. As you can see I used the 0-150 since our cars get up close to 100 psi and best to use a range in the middle of the gauge range. You will need to cut the harness and add wire as it won't reach up to the right front where our oil filter housing is. Makes it easy to fish the wire through the fire wall with the end plug snipped off. Just cut it about 12" above the plug end that the sender plugs into. I open the relay box under the right cowl (smg relay box) in the engine bay and using a flashing inside the car behind the glove box, you'll see the light from outside looking into the relay box. Run mechanics wire from the outside through the hole in the firewall and it comes out behind the glove box. Now attach the cut harness end with duct tape to the wire and pull it up through from outside. Solider your wire back together with extensions and cover with heat shrink hose.

To power the gauge you need to find a wire that is hot with KL15 (ignition on). I think I tapped into the + wire that powers the power point plug up under the passenger foot well. Drop that panel and check that wire with key on. Ground (-) is easy to find anywhere and may have used the power point ground.

Pay attention to the fitting you just bought to where it screws into the oil filter housing. I think I used 2 copper crush washers to get that to seat. Same washers that go on the oil drain plug since the threads are the same 12mm x1.5.

Be interested in your pressure readings as mine are now slightly higher with the BE bearings. 39-40 hot idle and 79-80 cruising. Cold start 93-95.

 

[Garfunkgrin]

Cant find any of these adapter fittings! Well, other than the stupidly expensive ones $80+...