Hi all,
I have a 2007 MCS hatch. There is a sensor that is located under the bonnet that is leaking. I don't know which sensor it is or what it does exactly but it is saturated in oil and leaking to the ground beneath it. I was hoping you guys could educate me a bit on what it is and what I should do. The sensor is beneath the coolant reservoir on the right side of the engine. Thanks,
Tyler

 

Take a photo if you would please. Your bound to get a response and what issues it could cause by going bad and whatever else.

 

Its too deep under the car to take a photo. I'd have to lift the car to do so :/

 

Sorry, hard to help w/o some idea which sensor you're talking about

 

From other threads I've read(which weren't much help) it seems it may be one of the 2 cam sensors. Not positive. But I know one is with the valve cover and the other is lower into the bonnet. I'm thinking it could be that, but again, not positive what it is exactly.

 

Ok well, let's try to analyze as best we can then. If your leak is around the coolant tank area. That's be car left side/drivers side. The cam sensors are on too of the valve cover. Atleast for the intake side. I'm using my memory so bare with me. The only thing under or around the coolant tank area would be the oil pressure sensor, oil filter housing, oil to water cooler attached to the filter assembly, drain lines for the turbo but it's more towards the center of the car, oil line that attaches to the block under the turbo but next to the filter assembly. So, I'd get a can of brakeklean, a flash light and clean the subject area as best ya can. Let it dry. And investigate further. There's quite a few options it could be with very little info given. Love to help ya tho.

 

Thanks for your help! I'll get some brakeclean ang figure out how bad its actually leaking. From what you said I'm thinking it might be the oil pressure sensor. I'll get under the car as soon as I can to get a good look and some pictures. Updates to come!

 

The oil pressure sensor is located just forward of the thermostat housing on the end of the cylinder head. Has a single wire connector going to it. It would be under the intake duct going from the turbo to the air box/air cleaner

 

Yep that sounds like it. Its soaked in oil. Do you think just replacing it will be fine? It seems pretty straight forward. I'm not getting any codes as of yet.

 

Yes

 

Gotta use thread sealant on it. But not enough that it makes a huge mess and gets into the oil passage.

 

Oil pressure senders are common leak items on other cars as well. I carry a spare in the trunk of my tii.

The ones for the N14 are costing around $18 last I checked. Use a new sealing ring. Can't remember if it was an o-ring or not. Usually it's a crush washer.

The bummer is that an oil leak one spot can get blown all around the engine bay making it hard to pinpoint.

Brakekleen is your friend here. Engine off, spray clean the area as has been recommended. Use safety glasses. Brakekleen in the eyes hurts. (I know) Maybe take a short drive, then see if you can tell if that's the leak.

Also, poke around on-line and find a picture of the area you are talking about. Exploded parts diagrams on RealOEM.com can help us know where you are looking.

 

SteveJ, I do believe you are on the money. I forgot about the crush washer thing. Yup yup.

 

You've been great help! I definitely wanna figure out for sure where the oil is coming from before I spend a dime, cheap part or not. Goggles and gloves are on my list of necessities for every project. I've been looking for a diagram! Thanks I appreciate it

 

Here's the screen from RealOEM. Poke around there if you haven't done so yet.

Oil pressure sensor is shown on the front left drivers side (right side of the screen here) Item #11. Part # 12-61-7-568-481.
There is a special sealing washer used- it is an aluminum crush washer that also has a center rubber seal on it. Part # 12-61-7-546-239.

It resides in front of/above the thermostat housing and below the exhaust vacuum assembly on the drivers/left side of the cylinder head. It may be tight to get a wrench in there. It takes a 22mm (a 7/8" will also fit). With the wire connector off, the grey plastic part of the sensor sticks out about 30mm, so a deep socket may also fit. Be gentle on removing the connector- it seems every connector on the MINI uses a different method to release. Some squeeze, some you press a single release tab, some have 2 tabs, etc...

Recently, I found our pressure sender was fairly loose. Only took a light nudge on the wrench before I could spin it out.