Back a few months I started to get a flickering oil pressure light when I would shift. It would only be on for a second, and since I have an oil pressure gauge that is plumbed very close to the factory pressure switch, and it read good, I assumed that the switch may be going bad.

I purchased a new switch and during the subsequent oil change, I replaced the switch. All is good, until I get the flickering again. Pull the oil filter to see if it is in backwards. Nope, all good there.

This week, oil light flickering even more often. OK stop driving car even though my gauge is reading fine. Yes, I do have the filter in correctly and following some other threads I figured that the oil bypass valve is broken. So I open up the filter again and to my surprise, the OBV is intact!

Now I am stumped. What could this be? Wiring? dash contol module? Oil bypass valve faulty? Oil pressure switch bad (again)? Major engine problems?
Remember my Autometer gauge is reading ~60PSI cold and ~35 at full tilt hot. I use Redline 5W30 oil. I also noticed that the flickering only seems to occur when the temp outside is warm (70F+) and the engine is hot.

Any ideas? This is a 2003 MCS with about 45K miles on it.

Mike

 

That sounds like a wiring issue. Check and make sure you did not bump or accidently kink the wiring near the oil pressure switch. If the switch has a harness, pull it apart and make sure the contacts do not appear to have any crud or rust on them.

 

That is what I thought too, but there is only one wire going to the switch. I have to get someone to sit in the car while I wiggle the wire to see if it makes the light come on.

 

I'm not sure I agree with the wiring diagnosis. If the light is coming on as the revs drop, but is out under what normally would be high-oil-pressure situations, it sounds like you are getting some sort of signal from the switch. If there were a ground fault in the wiring, I think the light would be more random. That having been said, I don't have an immediate better diagnosis for you

 

Well, I suggested it was wiring because you mentioned it occurs at 70 degrees F or above. That would suggest heat expansion. I have never seen the wire going to the oil pressure switch in a MINI. If it is a single lead, and it "clips" on metal to metal, just make sure it's seated well. Sometimes I have to use a pair of needle-nose pliers to bend inward the curled edges of the female connector to make sure there is a snug fit.

I'm sure you have done so, but try to be observant of oil pressure fluctuations. Maybe have a passenger with you so they can do it. If it jumps erratically, even for a split second, perhaps there is something more serious, such as a failing oil pump. But I doubt that is the case.

 

My guess would also be a wiring issue,follow the harness from the switch and see if it comes in contact with the body or other metal part that it could ground on.Look for signs of abrasion or pinching.A tiny split is enough and it is probably grounding intermittantly when a harmonic starts things buzzing and vibrating enough to cause contact. To isolate it you may want to disconnect the wire from the switch but leave it in its same position and see if the light still comes on.

 

I'd assume it is an oiling issue until you can prove otherwise. I'm wondering if there is an easy way to hook up a mechanical gauge to see what the actual pressure is at idle & above. If you continue driving thinking it's just wiring & it turns out not to be you will ruin your engine.

 

I do have a gauge and it is hooked up very near where the oil pressure switch is located. The gauge has never read low. It does vary from 0 when the engine is off to about 70 or so when it is cold and stays around 35 at speed on the freeway.

When the light is flickering, the gauge has always read ~30+.

Just found this thread...
https://www.northamericanmotoring.co...-comes-on.html

towards the bottom of the thread one message mentions the harness as being the culprit.

I will check it out.

 

Well since you have a gauge you know the real story. Glad to hear that. Now to find the wiring gremlin's.

 

After removing all the heat shields to get to the wiring, the only thing I found was the wiring was tie-wrapped to the starter pretty tight. I removed the tie-wrap, rerouted the wires and retied them. I also bent the heat shields so they could not contact any wiring.

It all works now, but I have not had a hot day to drive it yet. We will see in the next few weeks how it goes. I still have very good oil pressure in all conditions, verified by the gauge.

Thanks for all your help,

Mike

 

Thanks for the update.

 

I also need to check that wire. Somewhere in the middle, it's zapped and mine doesn't come on at all even with low oil pressure situation. If you have any pictures or diagrams where this wire goes, or even some instructions to remove the heat shield you removed , that'd be really appreciated.
Thanks !!

 

No pictures, but you can find some of the oil filter housing on this site using the search. The switch threads into that housing and the wire/connector attaches to it. It is a single wire that goes toward the drivers side of the car under the starter heat shield that is held in place by one screw to the oil filter housing and two pins (slip fit) on the transmission housing. One of the pins is under the starter and you cannot see it from the top of the engine. This shield is under the exhaust manifold. It is easy to take off, but a B*^CH to put back on. There is also a heat shield above the exhaust manifold that is held in with two bolts. That one is easy to get off. I recommend taking this one off first.
Once you get the one off the starter, the wiring will be visible. That oil pressure sensor wire merges with two other wires at the starter then continues into a larger piece of harness at the back of the engine (near where the transmission mates to the engine).

Good Luck,
Mike

 

Thank you very much for the update. So... you are saying that.... this can be done from the above without crawling down under the engine?
I once tried to follow the line from the oil filter housing from above the engine, but I ended up after 30Cm from the oil filter housing. If the shield is hard to put back on, I don't want to touch it.. :(
Anyways, I'll try this from upside as well as under the engine soon again.

Thank you very much!!

 

Most of it can be done from above. Reinstalling the lower pin on heat shield for the starter is difficult from above. You will probably be best off raising the front of the car and putting it on jackstands. That way if you need to get down there, it is easy.

I eneded up taking quite a few things off, like the PS fan underneath just to get access for my hands up to the shields/screws/etc. Like I said, getting it off is the easy part. Putting it back together is more difficult.

 

Thanks again for the great tip!!

 

Update: I don't want to jinx it, but I have driven the MINI for two days in warm weather without a flicker. I guess the wire rerouting did the trick.

Mike

 

That's very promising!

 

I am having a similar issue with my 03 MCS. Checked the the oil filter itself and it is in correctly. Replaced the Oil Pressure Sending Unit (near the filter) and the light is still on. Checked the pressure with an external gauge and it has 30 psi at idle (when warm) and 60 psi at 3000 rpm. Wiggling the wire to the sending unit make the light come on and off. We are going to wiggle it to get it to a place where it stays off and I am buying the gauge pack that mounts by the tachometer. I am thinking an oil pressure gauge and boost gauge.

Here is a video I shot of the Oil Pressure Light doing its thing.

http://www.youtube.com/watch?v=9pPSuMnZtC4


Any thoughts or ideas would be appreciated.. Thanks.

 

Just posted a video of my light in action. It might help. Thanks.

 

You guys are not going to believe how I fixed this Oil light flickering problem. I have a 2003 Mini Cooper S. I've had this problem for about a month now.

Went to the dealership to get this looked at. They told me that I need to change the oil. Replaced the oil but the problem still persists. After that they told me that the Oil pressure switch needs to be replaced. They replaced they pressure switch but didn't fix the problem. Then they told me that bad wiring. That also didn't fix the problem.

The Oil light only flickers when the car is warm.

Yesterday the car would not start and all of the gauges were going haywire and lights started flickering when I tried starting it.

Replacing the Battery fixed it! Still had the original 2003 Mini Cooper battery.

I've driven the car for about 60 miles and did not see the oil lamp blink!

 

Just wanted to respond to this, I had a similar problem that was happening for a few weeks. The dealer replaced the sensor and the wire to it, no dice. Eventually, they came across two things, it was either the engine itself, or the instrument assembly. They held on to it over night, unplugged the sensor, the light still came on (it shoulda stayed off without the sensor). They replaced the instrument assembly, no issues since, been 2 weeks. 108000 miles.