2004 mini with a manual midland, there is a sensor on the top of the gearbox that sits in a recessed square that is full of fluid. I can understand that part of the leak but what is blowing my mind is the tab that sticks out of the back of the block just under the exhaust header on the transmission side, its kinda in the same space as the trans sensor but i feel it sits a little higher so it should not be wet, the car runs and drives fine. Im scared to think that the head gasket is leaking and also i have noticed that my anti freeze levels are not consistent but with no evidence of leaks at all, and i have looked around. I was thinking the best thing i could do now is to troubleshoot and fix the sensor and see if the leak continues form the back of the block on the tab........see picture of the tab in question and sensor below.



after giving it some thought, it is possible i think that i could have spilled some oil when changing it at the last change but that was over a month ago......???? just a thought though

 

Clean the area with some degreaser and drive it. Inspect the area after a week or 2. Give it a go and report back.

 

Not sure how much effort you want to expend, but a pro way of detecting leak is to put UV dye in the oil & use a blacklight-flashlight to see the oil trace.

 

can i get that type of dye at a auto parts store??

thanks,

 

I googled that & see that advance auto & wally's both carry it.

I have seen small UV flashlights, you might have to google that too.

 

 

i do need to do some checking, i did have the thought that my bottle had a crack in it and that it might be misting out of the bottle because there are literally no signs of a leak. My mini is currently sitting in the driveway as i need to clean off the oil leaked fluid before i drive it again.

 

Update: we did a pressure test on the coolant system, results from that was some seepage around the thermostat housing. Today i am going to order a new thermostat housing, thermostat, and gasket and hopefully that cures the leak. What i thought was oil that had collected on the transmission and the ground was actually antifreeze. I use the Zerex brand that was recommended from the forum and if i remember right its a darkish brown fluid, maybe?? . It had fooled me in thinking it was oil, but when i checked for the leak again the fluid that had collected near the reverse light switch had evaporated. Fool me once sometimes but fool me twice, get outa here.

Let you know how the install and results go when its done, thanks

 

Got the parts and after removing the old thermostat housing you could see that the old gasket was hard and not all that pliable, you could understand why it had developed a leak, new parts in and leak has been absent since. No head gasket worries it was all the thermo gasket. The valve head is slightly bigger in size than the cylinder block, so it created a drip edge from the thermostat to the exhaust manifold creating the smoke that i was seeing..

Just wanted to mention this fix was real easy to do and i guess that goes along with all the other things i have had to do, except for the front control arm bushings that still need to be installed. Thats only because i opted to go for new brackets witch i think requires that you have to lower the sub frame......

 

Great news on the repair, it's always nice to have a good ending 👍