I just noticed yesterday that my '09 Clubman S, with 58k miles, has developed a coolant leak on the driveway. I just noticed it being low on coolant about a week ago. Now, this large wet spot shows up out of nowhere.

I have filled the collant tank up a couple of times today and driven it a little bit and it keeps sucking the coolant down. The last time I drove it, I ran both the A/C and the heater and both worked normally. When I got back home, the coolant tank was empty again and the car was dripping coolant at a steady rate. It is dripping to the left of center on the back side of the engine between the engine and firewall. I have looked underneath with a mirror in hand and cant see the source of the drip. It is dripping down the back side of the transmission. I also can't see anything from the top of the engine.

I will hopefully be able to get the car up on a lift in the next couple of days to get a better look at things. Before I get the car in the air, I am trying to find out what I need to be looking for. I see water pumps, and thermostat housings are common sources of leaks. I just don't know where those components are located to check them. I don't know if its a leaky water line, the pump, thermostat housing, or something else.

I am looking for any tips or advice that may be useful is diagnosing my problem. I can't find the link someone posted in another "coolant/water leak" thread about where things are located around the engine bay. All I have right now is my owners manual, and that diagram of the engine bay isn't much help in this situation.

Any help is appreciated.

 

Is that the left as you're sitting in the car or standing in front of the engine bay? Water pump is on the passenger side. Thermostat is on the drivers side. If its leaking down the transmission it sounds like the thermostat. Common failure.

Sent from my DROID RAZR HD using NAMotoring

 

Oops! My phone was posting replies when I thought it wasn't.

 

oops! My phone was posting replies when I thought it wasn't.

 

Thanks for your reply. The leak is dripping down the transmission from somewhere above. It is coming off the bottom of the car right even with the front axle, and just about 10" left(from driver's perspective)of center. When you say it could be the thermostat, is that the housing or the actual thermostat?

After filling the car up with coolant tonight, and driving a little to circulate coolant, the leak has turned into a constant trickle. I am not going to drive it any more until I get it to the garage.

 

The thermostat is built into the housing. Sounds like it will likely need replacing.

 

Looks like you need this. number 4 in pic

 

What is #4 in the picture? It looks like a gasket?

 

#4 refers to the whole thermostat assembly not just the gasket. It's pointing to the big box that is enclosing everything.

This is what you want... http://www.ecstuning.com/Mini-2009-C...ostat/ES25098/

 

Thank you, everyone for the replies. I will check out the thermostat housing when I get a chance to really look at the problem.

 

Is that the one that is a plastic unit? And is a metal one available? I saw this happen to a R56.

 

This is for the R56+ , just wanted to make sure. No metal one on the market. I have changed mine out on the R56 Cooper S with the new updated unit and its been doing very well, no isssues. I did the water pump ( passenger side ) also at the same time, they have changed that to metal now on the aftermarket and the OEM MINI one.

Coolant hit list w/ DIY for thermostat and water pump. There is a link to the thermostat DIY also.

https://www.northamericanmotoring.co...8-no-heat.html

 

I got the car up on a lift today to see where the leak was coming from, and you guys were right. It looks like it's leaking from the thermostat housing. Thanks for the links.

My new question is why do people change the thermostat housing and the water pump at the same time? Aren't they on opposite ends of the engine? I have ordered parts for a couple jobs on the car, but didn't order a water pump.

 

Yes in the mini they're on different sides of the engine. In lots of cars its pretty much the same job to do the water pump and timing belt so they are done together. With the mini and considering your miles I would just do the thermostat.

Sent from my Nexus 10 using NAMotoring

 

Yea, do it while you are there I had the thermostat go and had the older plastic water pump, tends to leak at the bottom. New water pump is metal housing and, The aux water pump is on the front ( most under the recall from MINI ). Once I changed the thermostat housing the main pump started to leak a day later. Its fixing both problems at once since you are there.

 

Does anyone know if MINI performs the aux water pump recall do they typically do anything else on the cooling system at that time? Meaning, they wouldn't do anything to the main pump or thermostat?

I bought my '09 MCS used with 48k on it. It has 52k now. From my research pre-purchase, I know the aux water pump was taken care of. Just not sure if I've got the metal main pump or not. I'll have to see if I can see it.

 

Anything else : No, unless it was complained about or fault while under warranty. Most aux water pump recalls ( little pump in front of the transmission ) is just the pump and then they top off MINI coolant and re-bled the air out of the system.

You will have to have them pull you records at the MINI dealership with the VIN if warranty or customer had done at dealership for other things. If the customer did it for some reason outside of the dealership, look for the metal pump outside on the Main water pump on the passenger side. Use my link above for the guide. On the Thermostat housing its hard to tell unless it was documented.

Thanks

 

Thanks!

However, after re-reading a post from above, I know for a fact that my timing chain was replaced around the 36k mark by a MINI dealership. I'll still look to see if its a metal housing.

 

Welcome. Metal housing is just for the main water pump, not the aux one. OEM and aftermarket are both metal now.