I have a 2011 Mini Cooper S convertible 6 speed with the N-18 engine and it has 60,000 miles on it. I have a very bad coolant leak. It is leaking coolant with the engine cold and not running.. If I add coolant to the reservoir it leaks down steady until it is empty. It is leaking under the passenger side and the coolant drips off the back side of the oil pan as the coolant runs across it. Meaning the coolant leaks all along the back side of the oil pan and then runs and drips from the motor mount that is behind the oil pan and then runs down the passenger side of the underbody cross member where it drips there too.

I cannot see if it is leaking from the water pump or the coolant crossover pipe. Any ideas on how to try to confirm if it is the water pump leaking or the coolant crossover pipe because replacing each part is a totally different technique? I don't want to work on replacing the coolant crossover pipe if it is the water pump because each repair is totally different.

Thanks for any suggestions...

 

Since coolant is dripping with the engine cold and not running:
Wait until no more coolant comes out, remove the front right wheel and liner, remove the water pump pulley, lie down and dry the lower half of the pump and as much around its gasket area as possible. Then fill with water. Look whether coolant leaks from the water pump's side or not (i.e.: whether the water pump gets wet anywhere but at its lowest point).

I've posted pictures of water pumps and the recess where they are fitted on a german forum:
https://www.mini2.info/showthread.php?tid=66933

It is unlikely that the water pump will get wet if the pipe or pipe gasket are leaking (imho).

PS.: It helps to have long fingers and thin hands!

 

That sounds like a good plan!
Thanks for your reply!

 

One stop pouring coolant in there, go straight to water till you find where the leak is. Pull the passenger wheel liner completely out and you should be able to see the water pump, take you stock air box off and that will give you some room to see from above. You can also reach up from passenger side, about the middle of the pulley, back side of the block you can feel where the tube connects and where it is most likely broken. Once you get everything fix to test to make sure you have it fixed, use a cleaned out and dry brake bleeder to put 15 lbs on the coolant reservoir, if she holds then proceed to fill and bleed.

This is mine from back in may when I replaced my water pipe. You will need almost 2 gallons of coolant, my recommendation is buy the mini coolant that isn’t mixed and mix with distilled water, it will yield 2 gallons and be cheaper than buying premixed.

 

Thanks for the advice. I was able to see the weep holes on the water pump from looking up from the bottom of the car and they are dry but looking at the pictures from the previous poster, it looks like the water pump can also leak at the gasket as well as the weep holes. Is that correct?

 

I’m sure the gasket can leak, but that water pipe tends to break inside the water pump and leaks down that corner, but more on the back of the block.

 

I have a feeling that it is the coolant crossover pipe. From what you have said it does leak down the block. I better get ready for a big job. Thanks for your help...

 

If I were you I would replace thermostat and the water pipe. But first I would get that water pipe off and feel if your water pump has plastic blades or metal. If metal, your probably ok, if plastic swap it out. Aaron at outmotoring should be able to hook you up with anything you need, pretty sure he gets in around 830 am or so EST.

 

Now the leak has stopped. It was leaking bad and now today it does not leak. The water crossover pipe does look the wettest. I am wondering if the thermostat is now closed and will not let water pass to get to the crossover pipe where it was leaking like crazy yesterday. I guess I will replace the electronic thermostat and housing and the crossover pipe and probably the water pump. Crazy that big leak just stopped like that.

 

If you are going to replace all of that, pick up a gallon of mini coolant, it’s not pre mixed so you will be able to mix up 2 gallons and have plenty for this job, and will be cheaper than picking up 2 gallons of premixed stuff. You can fill it with water and put 15lbs of pressure on the coolant reservoir to check for leaks now, do it dry when you replace everything.

 

That is a good idea to do the pressure check with water in the engine before going to coolant. It is so bizarre that water was leaking out as fast as I could fill the reservoir and today there are no leaks and absolutely nothing has changed. I had it on jack stands yesterday and it was leaking and then I go out this morning and it is still on jack stands and now has not lost any water that I put in the reservoir. I have worked on cars since I was about 12 years old but I have never ran into a car with a water pump that does not turn until the ECU pulls in the friction disk and never worked on a car with an electronic thermostat. This car is my 79 year old mothers car. I drive a Camaro Z28. I have to make sure I fix this right because I don't want her stranded on the side of the road. I really appreciate your advice and help! Thank You..

 

Lucky for you YouTube is full of videos and this forum has some how to’s on these replacements and if you want the online manuals access just send me a pm with your email address and you will get an invite back from the site.

 

Is there a PDF service manual that you know of?

 

Send me your email in a private message and I’ll send you an invite to an online bmw/mini website. I can’t mention their name in fear that they will lock my account. I have been passing out free accounts since December last year. Trust me worth it. Real oem.com great for parts pics and part numbers

 

Hey Jason, I pressurized the system and it held the pressure for about 10 minutes and did not leak. I did this with the engine and coolant cold. Then I released the pressure, left the coolant cap off and hooked up my phone to my ELM 327 Bluetooth OBD II so I could watch coolant temperature. I cranked the car and watched for leaks and there were none until about 5 minutes of run time and a coolant temp of 160F then it began to leak. Most of the coolant was dripping off the passengers side rear corner oil pan bolt. The one nearest to the passengers tire. I am thinking it is the water pump. This is the first day it has not rained in a couple of days so I was able to get out and work on the car. I think I am gonna go ahead and start with the water pump first. What do you think?

 

If it's dripping down the pan, I believe it's the water pipe.charges. very similar drip and I could never see it. Even with a camera. I ended up dropping the water pump and replacing it for no reason. After I restarted car it was leaking again. For a second time I replaced the water pipe, this time I bought the mini brand name. I could see the difference was the o ring. I had to really twist and turn the pipe to get it to fit. I used a small dab of dawn liquid on o-ring to finally get it to fit. Even the thermostat housing was difficult to seat. I had to push it fully onto pipe with the bolts.
I believe you are chasing the wrong area. Just my opinion worth price charged.

 

Thanks for your response. You said you couldn't see the leak even with an inspection camera. I just ordered one 2 days ago. This is the most trouble I have had trying to diagnose a coolant leak in my life, lol. I will wait until my inspection camera comes and if I cannot see the leak I think I will take your advice as you are the third person to mention the crossover coolant pipe...

 

I'm glad to hear that I had support with this recommendation. The whole purpose of this site is to gather information. Hoping that someone has the hands on experience with same issue you are having. I was underneath my car with it all jacked up, trying to see where leak was coming from.. lying in a puddle of the blue antifreeze. Oh no, grasshopper, it wasn't happening, couldn't see it. If I'm not mistaken I even did it with the tire off. It comes from the back side and drips funny down the wheel well and onto the oil pan. You can't really see. It's mucked up. If you have replaced the water pipe at least make sure you buy the Mini O rings. Pelican parts has them at a reasonable price. Just saying, they fitt way tighter than Febi that I tried 1st time.
You got this.

 

How long did your Febi pipe last?

I've just gone through the exercise of replacing thermostat and water pipe - I bought the BurgaFlex brand as it was the only non-Mini in stock at the time and I baulked at paying over 3x the price for the Mini branded version. It required a lot of effort to get in place so was hoping it was a tight seal.

Now I have a coolant leak on the water pump side and I'm trying to decide whether it's the pump or the 3 week installed pipe (about 500miles). Everything was fine until last Wednesday when the leak developed - solidarity in failure from the pump? Will get in there this weekend. I have a replacement pump and pulley on hand.

If it turns out it's the pipe I'll leave a negative review so others don't waste their time on that brand. I assume you can't replace the pipe from the pump side?

cheers
MacMini34

 

After installing Febi, I still had a drip at the water pump area. I was so mad that I replaced it with the OEM. After I began installing OEM I realized the difference was the O-ring. The OEM one fit snugger. I would have kept the Febi if I had known. I have it laying around here somewhere. I should have bought several extra O-rings, but was thinking I won't be doing this again. Yeah, sure I won't be...... I must be nuts having this car. The only time in my life I didn't do my homework on the car before purchasing

Buy 2 new OEM O-rings ~8$ at Pelican. Put em both ends of the pipe. You'll see what I was talking about, going back in. It was difficult because it was so tight. I read someone say Dawn used only on the Oring allowed it to be more slippery that mineral oil or glycerin. They were right and it din't foam my antifreeze..........

 

I must be nuttier - I did a lot of reading on this forum and still bought one!

 

I installed a Burgaflex water pipe in my 2009 R56 base.

It was a terrible experience. I fitted one end into the block at the water pump, but had one awful time mating the pipe to the Thermostat as the rubber O-ring would not stay in place. After an eternity, I got everything back together.

A few weeks later, the pipe developed a slow leak at the water pump end.

Replacing the pipe is such a difficult job, I'm sticking with a Mini pipe next time.

 

I posted this in another thread but think it will be useful here as well.

The water pump on my car failed at the bearings, still usable but the impeller was no longer exactly where it should be. As a result, the impeller chewed up the water pipe. I figured I would change out the thermostat housing to keep from having to go back in there in a short period of time. I changed out the thermostat housing, water pipe, and water pump with MINI branded parts purchased from ECS. That was over 14,000 coolant leak free miles ago.

 

Just want to make sure - was your bad experience because the Burgaflex water pipe didn't fit like the MINI pipe would have fitted?

 

Yes, the O ring did not fit snugly, which made it VERY difficult to fit into the thermostat side. It took a very long time using trial and error.

It then wound up leaking at the water pump end.