A few weeks ago, I did my first oil change on my 2010 JCW, and everything went smoothly, but a few days after, I noticed it was leaking some fluid onto my driveway. Ended up being coolant, I topped it off, and saved the issue for a warmer day, as it wasn't having overheating problems. I've had to top it off again a few times, but the system still holds at least enough pressure to make an audible pop when I open up the fill cap.
I checked the coolant reservoir as that's the only thing I had to move while changing the oil, but the leak doesn't seem to be coming from there. Are there any other common places to have coolant leak from on an R56 that are around the same area? Since it's holding pressure, I doubt a pressure test would help me find it, and I'd prefer to not add any UV dye if I don't have to.

 

Look on top of your transmission on the driver side of the car, underneath the air intake hose. If you see coolant pooling on top, that usually indicates that your thermostat is leaking. This is a common leak, and a reasonably able person can change it out. Hint:Change your coolant temp sensor out while you're there.

Also, look underneath your engine on the passenger side. If you can see coolant dripping from the wishbone or the output shaft, or if this where it is pooling underneath the engine, then you have a water pump leak, also common. The good news is that the replacement pump will be metal, not plastic, and it's pretty inexpensive. Hint: change your water pipe and gasket while you're there. The bad news is that it's a tedious job -it took me about three hours, but it wasn't that technical.

Good luck, and give us some feedback on whether or not this is where your leaks are.

 

It's really common for the hose that connects to the expansion tank to leak when you flip it over to do the oil change, but when you put it in place it stops leaking. So that is the easiest and free fix.

Otherwise you would need to actually put a pressure tester on it to diagnose. Keep in mind it may only leak while it is warm.

 

Apologies for the slow response, thanks, guys, for helping me out.
This leak actually stopped on its own, I was waiting for it to not be freezing outside to take a look at it, and then I was waiting for it to leak again so I could see where it was coming from, but it never actually did leak again. Weird. I'll keep an eye on it, though, and double check the areas that were mentioned.

 

https://www.pelicanparts.com/techart...eplacement.htm

Figure 17 shows a hose that my oil pressure sensor had been slowly dripping oil onto. My hose swelled up and it was leaking right there. I ended up replacing my thermostat in the process because i didn't initially realize the leak was there. Also replaced the pressure sensor.

I've also had coolant leak out of the down spout when changing the oil, but it has never leaked there once it's back in position.