Been a while since I've visited the site. So hey guys!

So I recently changed the oil on my 2004 MCS and sometimes the oil light will stay on, other times it's off. This never happened before I'm sure. I read around that it is the oil pressure sensor, but why all a sudden after an oil change? I used a MANN filter with gasket if it matters any.

Should I replace this sensor, and is it easy? (haven't looked yet)

 

Oil light illuminates is not to be taken lightly. Better do a search on oil filter housing drain back valve failure. Yes. You can be lucky and the oil pressure switch just happen to fail so coincidently. You can also be not lucky...

 

I would remove the filter and make sure the plunger in the housing isn't broken if it is you need a new filter housing.
Also I only use the factory MINI filters as we found aftermarkets having many more issues like this.

 

Thanks guys I'll look into this.

 

I had the exact same issue after an oil change over the weekend. I just replaced the oil filter after reading I might have crushed it during the install. Athough I was pretty sure I didn't crush it, it was the the first step. No dice, light is still coming on.

Keep me posted on how it turns out for you.

 

Fixed it a while back, although I'm not quite sure what it was. Originally I used a MANN filter, and after reading that they can cause issues, I replaced the filter with an OEM filter. However, at the same time I also replaced the Oil Pressure sensor/switch, since it's right there anyways.

Problem fixed ever since. Next oil change will be with an OEM filter, just incase that was it.

 

It it were me I would not call it fixed unless I am pretty sure it was the oil pressure switch. If it were me I would want to check the oil pressure with a gauge. Oil pressure switch A can just be triggered slightly higher than B that replaced it.

 

​​​​​Ok thanks. I'm going to change the sensor tomorrow. Fingers crossed.

 

I experienced the same problem a year ago i changed oil as normal routine and then i see oil pressure low once in a while when sitting and stuck in traffic, then it clear, i checked everything oil level changed the oil pressure switch and still intermittently getting the low oil pressure so i bought a kit to monitor oil pressure while removing the pressure sensor oil was coming out and i decided to change oil instead, then i sticked my finger inside the oil filter housing and discovered a piece of plastic with spring fell-off i don't know where it belong so i did the research... It was an oil drain back valve and "NO ONE SELLS THEM" you need to buy the entire oil filter housing around 250-600 depending which store, dealer asking for $600 with the oil cooler if its Manual Transmission.
I went to junk yard and luckily found Cooper S sitting so i bought it for $30.00
I just installed the oil filter housing never disconnect the oil cooler ( eliminate air bubbles in the cooling system lazy to pull vacuum/ evacuate the system again) and at the same time installed the digital oil pressure gauge.. It works and running fine now... Idle pressure runs around 20 PSI and 50 something around 3000 RPM, im not a mechanic so i just figure it out myself..FYI
My car is 2002 MCS

 

Yep, that's the drain back valve pnwR53S was referring to. I've seen a thread where someone was able to repair it for a few dollars using a modified part from an auto parts store, and a more recent thread where someone is thinking about selling replacement cages based on 3D printed parts he designed.

 

This is the finished project yesterday. I can monitor engine temperature and oil pressure.

 

Good to hear that you carried out the proper diagnose, and invest in a pressure gauge. Some just want to kill the canary for screaming its head off.

Actually, I just read up on it. The poor bird actually goes quietly in the presence of dangerous gas. A better analogy is to replace the dead canary with one that is more robust, and keep on digging.

 

There is a finer point about the oil pressure switch, and some may not understand. It is design to detect the lost of oil pressure and not to cause a false alarm. It is set for about 4 PSI. It is set so low because at idle, under the worst possible temperature, the lowest viscosity oil etc. This pressure will is far from adequate when the engine is under heavy load. A healthy engine under load say at 3500 RPM needs to have tens of PSI oil pressure. Engine oil pressure is directly proportional to the RPM. The higher the RPM, the higher the oil pressure - to a limit.

If the drain back valve is compromised, or partially compromised, you are likely still have some oil pressure. It can be in the vicinity of just a few PSI at say 3500 RPM. This oil pressure may or may not trigger the oil pressure switch, even at idle. There lies the problem. By replacing the switch without checking the pressure at higher RPM, you may be gradually, or rapidly killing the engine.

 

​​​​​​So I changed the sensor yesterday, oil light is still on. I noticed that above 3500 RPM the oil light goes off.

Thoughts?

 

I found my problem, broken bypass valve.

 

If its in the filter housing, it is the drain back valve that tends to break. Sure it bypasses all right.

The purpose of a bypass valve is to let the oil go to the vital organs should the oil filter is clog up. The engine would still get adequate pressurize oil supply. Totally different animals.

 

Here is the thread where they talk about using another part to repair the plunger http://www.minitorque.com/forum/f26/...12-fix-119169/

I have it bookmarked for reference in case i need it. Now how well it works i can't speak to, but if you can modify a $6 part and it works it saves you from having to get a whole housing.

 

Very interesting. I gather you are referring to Dorman 904-261 in which the link is dead in that thread and the photo links are also dead thank to Photo-kicked-the-bucket ransom.

It is .

I have recently remarked in another thread not related to this that Dorman build a business making a lot of high demand parts that OEM failed to fix, and here is another one.

I bought a Dorman turbocharger resonator for my Sprinter that Mercedes engineer failed to fix even in an improved version . Upon comparison with the Mercedes improved part, I have no reservation it is simply superior and no brainer. Dorman is Chinese. And on the Sprinter forum most owners sneered that it must be a Chinese cheap junk, and go with a overprice US made aluminium tube instead. Needless to say, it is no longer a resonator that is designed to suppress the resonance of the turbocharger induction noise.

Sprinter's turbo resonator made by Dorman

 

Yes I am talking about the Dorman part. I checked a couple months ago at my local parts store and the part is still available for less the $10. I wish there was more information on if this is a viable long term solution to buying the whole housing.

I don't doubt there might be quality issues with the Dorman products, but as a temporary or emergency fix it is an option. Now as a long term solution I don't know how long I'd trust it.

Fyi the pictures are still active you just have to click on them.

 

Sorry for being vague. I fully endorse Dorman with my experience. I also bought their battery T-terminal bolt and it is no less than the OEM, but without the brain-dead end stop that cause you to kill the $20 bolt if you try to remove the nut to add a crimped lug. My experience is nothing but stellar. Companies like this, are to be judged by each product as they have cats and dogs.

 

Oil filter housing replaced over the weekend. Problem solved.