OIL PRESSURE FAQ
compiled & edited by Kristian #562
Please read the Disclaimer before attempting any work in this FAQ.
 

• OIL PRESSURE SENSOR
• Oil Pump Gears?

OIL PRESSURE SENSOR
by Justin #843 & Spakur
28/10/01

Symptoms:

You've got Oil seeping from SOMEWHERE behind the cylinder but you can't pin it down

OR

Your Oil Light is on and you can't find any leaks and you HAVE enough Oil in the Bike...

The part cost about US$12. The BMW part number is 12 63 7 670 015 (I think) If I am not totally wrong I think I have had some bubbles in my oil also sometimes.

• If you ever wonder where the hell oil leaks from, and can't pin it down to a gasket or loose bolts, may I suggest the Oil Pressure Sensor. (Shown here with the Rubber Cap removed and the Electrical connection off). It's an 11 dollar part with a rubber gasket/seal in it which fails. The gasket which holds the connector leaks profusely and is nicely positioned to channel oil all over the place. Front, back and pools up on the crank case.

• If you use the side-stand, the oil pools will run to the left over the left case leaving you to say, "Where the heck is that coming from?"

• Then you start worrying about the main gaskets etc. and "big" money. If you don't know where to look, its right above the oil filter cover and has a rubber boot and wire sticking out of it. If its greasy, its beginning to fail. I noticed that after really hot days, oil drips out in a steady amount. I guess the heat and extra oil expansion is pushing the connector higher?

• So how do I remove it.? Well it's a bit tricky to get to because it is just over the top of Exhaust Pipe so please do it when the Bike and the Exhaust Pipe are COLD.! if you happen to have your exhaust pipe off anyway the job is much easier.

• First gently pull off the rubber cap and then wiggle the electrical connection off the top of the Oil Pressure Sensor, holding the spade connector itself (never PULL the wire.!)

• You will need a 21mm Socket, a shorty, as while you'd think a long socket is more suitable to get over the Electrical Spade Connector bits, you can't get a socket on top of it. You can use a ring spanner to remove it, an open ended spanner is also possible but less recommended, but you will need to use a socket anyway so you can torque the new one into place. Now the shorty will of course be too short, but if you do NOT push the Socket Drive ALL the way into the socket it will work O.K. Here is what the are looks like with the Sensor Out.

• Screw in the New Sensor, adding a thin smear of oil to the seat and making sure it's clean before re-installing. The Tightening Torque is 24 Nm.

• Replace the spade connector, and the rubber cap. The Cap has a lip on the inside, make sure it's firmly over the Sensor.

Note 1: If it happened just after an Oil Change or Regular Service Check the Oil Filter O-Ring FIRST.  Or it could be some remaining wasted oil from the previous oil change, try to clean everything and check if some new oil comes sprouting out. Don't Forget check your oil level to prevent engine damage. There is also the frame oil drain plug, just above the exhaust pipe in front of the bike, which could be leaking. If you're unlucky, it could be the threads where your sump plug goes (bottom of the engine) that are destroyed, it's a well known problem and there is a BMW "fix" for it. If you're just out your 6k service, go back and ask for repair. Thanks to Francois. See also the Oil Leaks FAQ.

Note 2: Before going off and replacing the Sensor check that it isn't just a bad contact between the sensor and the electrical cable, what is very common in this bike, and the same occurs frequently with the contact of the radiator fan, both with the same fasten connector type. With the motor stopped, you can disconnect the cable of the oil pressure sensor, put it in mass with a metallic part of the motor and with the contact key in the on position the light must be lit. If this were your case, clean the contact and the problem must be solved. Fede

Note 3: If the Oil Pressure Light Stays on even AFTER a sensor replacement/Loose wire check, have the actual oil pressure measured. The last thing you want is to run a low pressure for an extended period. (= engine rebuild). If you don't have a mechanical gauge, most shops will give you a quick check for little $$. (I'm assuming there's a place to port into the oil galley---I haven't had to look into this possibility on my f650). Nate. A fitting for a proper oil pressure gauge should be screwed into the place where the oil pressure sensor normally goes. This will either verify or eliminate whether the actual pressure is at issue. Flash #412

Note 4: The Oil-Pressure Switch Threads are M10 x 1 - Haakon #626 (Norway-F650GS), in case you have another source.

Feedback:

• I was driving on the highway, just a couple of minutes from home going to the university when the oil light came on. When I saw that the light had lightened up I stopped by the side of the road. I checked the bike for oil leaks, but couldn't find any, so I started her up again. This time the light came on after 5-10 seconds and it faded on. I drove back home listening to the engine and watching the temperature. There was nothing strange with the engine noise or the water temp. I got back home and decided to top of the oil level a bit, since I thought it had been a while since the last top of. After that I started the bike up again, but the light came on and stayed on.... I guess it is not oil level related, so it could then be something with the oil pump - right? I have just been searching the FAQs and also found that it could be the Oil Pressure Switch. I checked the Switch and if I disconnect the cable, the light goes OFF, and if I connect the cable it goes ON. I also tried to start the engine up and the oil light fades halfway off for a couple off seconds and then fades on again (and stays on). I guess it must be the switch. I've got the parts Nr and the shop next to me is a BMW auto shop, where I usual buy my parts. I'll just go down and order a switch and hope it is that - which I guess it must, since the bike performs just like normal. It WORKS! it was the Switch. Spakur, #1117 Sweden.

• Besides the oil level check, put an eye on the oil light switch located over the engine case. It is easy the failure of this type of switch, the same type than the rear brake light switch. Those thinks are the most fragile thinks of the F650, at least in my experience. I'm almost sure you must change the oil switch. Try to disconnect the electric connection and with the key in the on position the oil light must be lighting on and contacting both cables the light must turn off. If this thing occur, the switch must be definitely changed. Fede

• For next time: If you're worried about your oil pressure, open your filler plug. Start engine and let idle. You can see the oil returning to the reservoir from the return hose. A sure sign that the oil pump is working. Werner #547, 2000 F650 Classic .

• (In response to the above) Hmmm... well there are TWO oil pumps. What you will SEE is the fact that the scavenging pump is working. What if the other one, the one that is supposed to supply PRESSURE to the system has some sort of breach. Your oil light lights up because there isn't enough PRESSURE to turn it off, yet the scavenging pump picks up all the oil that isn't going where it should and you SEE oil returning. Yeah, it is better than nothing I s' poze. I might remove the oil pressure sender and start the motor just to see the gusher and be SURE. Flash #412

• Q. How can one access the oil pumps - are they visible from the outside? A. They are behind the clutch. Remove the clutch basket and you will see their drive gears.

• Q. Has anyone had a oil pump failure? Not of which I am aware. But oil pumps don't usually fail on their own. Usually, the motor runs out of oil and THEN the pump fails. The rotors or gears in them score from lack of lubrication. Although, OUR pumps are driven by plastic push-on gears. Flash.

• Critical Oil Sensor Failure. I have changed two- both times the light warned me and both times I had a small oil seep from the sensor. Haakon #626.

• I bought 97 f 650 5 months ago after I bought I faced few problems. One of them and the worst one is oil pressure light is coming on and off but this is some different there is no problem until machine is normal heat (approximately 50-70 km) light is coming on and off when rev is 1400 but if I raise it more light comes off and I also there is no problem when riding. First I thought it was related to oil I changed it Castrol 20-50 but there was no change then I read FAQ and there it was advised to change pressure sensor I changed but but there was no change in his habit and it is now going on same as it began ...( there is no performance lost or working problem ) if you can help me I'll be glad. mete

• I just replaced mine. While covered under warranty, it's only an $11 part and takes about 10 min to replace on the GS. Not worth dropping the bike off even if they do provide loaners. Mike639.

• Classic f ~19,000 mi. On the way home the oil light came on. I pulled over to check, engine was not particularly hot. While the oil seemed slightly low the weird thing is that it seemed frothy... bubbles all along the dip stick. Rode it last 5 mi home. After it cooled I looked at oil and it looked normal... no bubbles. Next A.M. did the 1 min warm up to officially check level... it seemed ~1/3 qt low ( I use redline synth) no signs of chronic leak or burning. I reluctantly added oil ( bad experience in past overfilling) and have ridden ~20 miles since.. the oil light is still on. paul smith

Thanks to Werner, who owes me two beers, and of course to Justin.

Oil Pump Gear Problems?

by Flash 412

Q. How can one access the oil pumps - are they visible from the outside?
A. They are behind the clutch. Remove the clutch basket and you will see their drive gears.

Q. Has anyone had a oil pump failure?
A. Not of which I am aware. But oil pumps don't usually fail on their own. Usually, the motor runs out of oil and THEN the pump fails. The rotors or gears in them score from lack of lubrication. Although, OUR pumps are driven by plastic push-on gears.

Problem: I have a BMW F650 February 1994, with 36000 miles (more or less). I have a problem. I was going my holyday house. I stopped to buy something to eat and when I started again I heard a strange noise coming from the engine head. I checked and I found Oil was not circulating in my engine. I stopped immediately the bike and I carry it by a big car.  opened engine block and there I found one of the black plastic gears of the oil pump (the inferior one) out of its site inside the carter. At that moment I have bought both the plastic gears to replace them. The problem is: what could be the causes that have make possible this fact? In particular I’d like to know if changing all this two gears is the correct solution. Waiting to have a your feedback A big hi, Mario Cagliari, Sardinia, Italy '94 F650, Cagliari, Sardinia, Italy.

Questions:

• Does your oil pressure light work? Did it come on?

• Replacing the Gears might fix it and it might not.

• There are two questions. First, why did the gear pop off? And second, will replacing the gears fix ALL of your problems?

• I suspect that the gear popped off because of heat cycling. Maybe it was not installed properly in the first place. You will never know. Certainly replacing both gears is a good idea. After they're replaced, your problems MIGHT all be solved. But maybe not. It depends on how long the engine ran without proper oil pressure. There are two oil pumps. One pumps the oil in the engine back up to the oil reservoir under the gas tank and the other pumps the oil to the various bearings. Losing either one is a Bad Thing.

What to do:

• When you have replaced the gears and reassembled the bike, remove the oil pressure sensor and connect and oil GAUGE in it's place. You want to start the motor while observing the oil pressure. You want to ride it until the engine is HOT and then observe the oil pressure again. The "rule of thumb" for oil pressure is approximately 10 psi (~0.7 bar or atm) for every 1000 rpm. If the hot oil pressure is within 50% of that, and the bike doesn't make any funny noises, then everything is probably just fine.

Feedback:

• Personally, I have never been a fan of plastic or nylon gears in a hot engine. Eventually, over time and many heat cycles, the plastic material becomes brittle and may break. Of course, the fastener that holds the gears on the shaft can always come loose, too. This is an unusual problem that is very rare in the F650 engine. I don't think anyone here can advise you if replacing the gears will completely fix your engine, because we can not see your engine or its parts. Posting some pictures would likely help to give you better feed-back from our group. Based upon what you have described, it seems like replacing the gears and their carrier is the obvious solution to your problem. Richard #230: 1997 Funduro, 2002 R1150R, 2002 Yamaha YZ1, 1993 Honda CB750, 2003 Kawasaki 250R Ninja - Pacifica, CA, USA

• For next time: If you're worried about your oil pressure, open your filler plug. Start engine and let idle. You can see the oil returning to the reservoir from the return hose. A sure sign that the oil pump is working. Werner #547 -- 2000 F650 Classic -- 1991 R100 GSPD.

• Hmmm... well there are TWO oil pumps. What you will SEE is the fact that the scavenging pump is working. What if the other one, the one that is supposed to supply PRESSURE to the system has some sort of breach. Your oil light lights up because there isn't enough PRESSURE to turn it off, yet the scavenging pump picks up all the oil that isn't going where it should and you SEE oil returning. Yeah, it is better than nothing I s'poze. I might remove the oil pressure sender and start the motor just to see the gusher and be SURE. Flash 412 (CO)