Just finished this job too - 2008 R56 with only 45000km. This car had poor heat, showing a running temp of max 60C on the cluster, but no fault code stored. The cooling fan had started running constantly when the engine was running, and in the few days before replacement, was running 5-10 minutes even after the engine was shut off - and this is on a -5C winter day. Seems like the DME was in a fail-safe mode of some sort. Also had evidence of coolant weeping from around coolant temp sensor.

For the official record and for future searchers, the coolant temperature sensor plug (on the top of the thermo. housing) takes the connector with the yellow wire, the oil pressure switch that's threaded into the cylinder head takes the connector with the green wire.

 

I forgot about updating this thread. The codes were caused by a plug I failed to reattach, the plug towards the firewall, bottom. Once I connected it, she ran like a champ. Thanks though for replying. I appreciate it.

 

I've gotten the new thermostat in place, but now I'm stuck. I'm trying to get the clip back on the hose behind the engine block and I can't seem to seat it properly. Does anyone have any advice on how to seat it correctly?

 

This is a tough one since you can barely see it, it's cramped and its a spring clip. Here's what I did. Once I had the clip sitting in the right orientation I used a flat head screwdriver to press it into place. It won't take a lot of force to get it back on however you must make sure the connecting pipe is firmly seated so it's groove is exposed allowing the spring to slide on. Also, fool around with the old thermo. and clip to see exactly how the clip slides on. I suspect that your pipe isn't totally seated. Good luck!

 

Here is a picture I took of the clip before I pulled it out. The orientiation of the seated clip may help you to properly position it. If I recall it is leaning towards the engine and not standing straight up. It was also difficult for me to get this clip back in place. Took quite a few tries.
Also, another poster said that as you tighten down the thermostat housing the connection between the housing and the water pipe will seat correctly. I helped it along by lubricating the o-ring with some antifreeze.

 

Just came to say...
The thermostat in the mini and in the peugeot it is not the same!!!!! :(
(talking about the N14 1.6T R56s, the peugeot thermostat didn't come with the pipe to connect the hose from the coolant tank to the thermostat and getting back to the turbo... (It is like a Y... Coolant tank and turbo connect in a Y to make one single hose to connect to the thermostat... , everything else is the same... now... will check if the water pump its the same... (because a friend told me that it will be the same parts Peugeot and Mini... )
I draw with red the connection and with yellow where it make de Y.

 

I replaced the thermostat housing on a Mini Cooper S r56 yesterday.
After turning the car on this morning some little drop started on the passenger side of the car....

I did fight with the hose that connects the water pump with the thermostat to remove the bad thermostat yesterday.
Do you guys think I might disassembled the hose from the water pump?? Is that possible? How do you recommend to fix it?

This pipe:

http://new.minimania.com/part/G2NME1...0-61-Cooper--S

Thank a lot!

 

No, I don't think you disconnected the hose from the pump. You may have not seated the thermostat fully (bolted in unevenly), maybe didn't plug the housing in all the way and replaced the c-clip properly, or it could just be drops that came out when you pulled everything apart when removing the old unit.

Keep an eye on your coolant level; if the car isn't overheating and the coolant level isn't dropping, I'd bet it's just the stuff that fell out when you took it apart. Mine did the same thing; even smelled like hot antifreeze for a few days, all due to the mess I made when I took it apart

 

Thanks for the feedback Americanitis!

This morning the level was a bit below the max again, with cold engine was not dripping coolant anymore (not for the 30 seconds that i was looking at it) then I added coolant up to the max line, and started dripping again from the passenger side of the car drop by drop...

No leaks at all at the thermostat, did check this also.

Any ideas?

Thanks again for the help!

 

Did you bleed the cooling system? There is a screw on the top of the thermostat housing to let you bleed out the air. If you do not do this thoroughly, it will appear you are losing coolant when in reality you aren't as the air slowly comes to the top of the tank. It is possible you dislodged the hose from the pump. It would be hard to do, however, and you would've probably known you broke something. But it is more likely you spilled coolant all over the transmission and engine and then didn't fully bleed the cooling system. That is what usually happens doing this job. It happens every time I do it. I thought mine was leaking too because it seemed nothing fit together all that tight and everything was also fragile and plastic. Bleed the air out of the system, then keep an eye on the level. I wouldn't trust just seeing coolant dripping off the car. This car has 2 water pumps and will probably throw a code if the coolant is leaking or there's low pressure in the system. It's probably just the stuff you spilled changing everything out.

 

Also, this sounds silly, but make sure you closed the valve at the bottom of the radiator too.

I bled my system, and still had to add coolant over a few days. Once it gets up to level, it stays there, but with all the ports/pipes/nonsense, it can take a few days even if you bleed it properly.

 

Yes, I bled the system following the instructions of the Bentley manual and what I found here. I opened the bleeding screw on the top of the thermostat to do so.

Hope you are right, but I honestly think that this is not just coolant leftovers… This morning right after I filled the expansion tank to max level it started dripping again from the same place… it was not dripping before that... Passenger side, like 20" from the front of the car…

From where the coolant is coming and what I have read in this forum I have two options, water pump or dislodged water hose. With all this you still think that is coolant leftovers?

If I dislodged the hose from the pump will it be difficult to colocate it again? I just need to push it in right? I do not think I broke it (i hope haha) since I did not push it that hard it was more like wrestling trying to get the thermostat out.

Thanks for your help, I really appreciate it!

 

Unless you broke something, I'm not sure you could dislocate the hose on its backside...I think there's a clamp there, not just a clip like on the front. If you weren't prying there, I just don't see how you could've broken it. But I don't know your mechanical style

HOWEVER: keep an eye on the coolant level. I also have the Bentley manual, and followed its bleeding instructions. It STILL took a week for the level to come up and stay up. And I STILL was dripping coolant off the back of the motor and off the top of the transmission from what I spilled the entire time. Again, for about a week or so. I also live in PHX, so it would disappear faster here than just about anywhere else as it's so dry.

That being said, without seeing your car, I cannot diagnose it. Just letting you know I had the same sort of issues and to just keep an eye on it because the car has multiple coolant pathways that can all spill juice when you take the system apart. It leaks more than you'd think, even when you drain everything out of the bottom. It's possible you dislodged the hose at the water pump end, and from what I understand, the pumps can leak too. I believe the aux pump is actually a recall item, so if you determine that's where the leak is, it might be worth calling your dealer to see if your car has had that fixed. And if not, they may cover it. Also, the thermostat is a covered item, so long as the car has less than 50k miles and it's an electronic fault code, which is Federally-mandated as part of the emissions equipment. I found that out after I changed mine myself at my own expense

But my advice is to keep an eye on that level, and see where you are after a week of checking it every day. My hunch is that you didn't break anything and that the air is just working itself out AND the spillage is dripping/evaporating on the engine/transaxle. I'd also check the hose at the bottom of the tank: That has to be moved to do this job, it has to be moved to change the oil, and it's way more likely that the elbow at the bottom of the tank or that little hose was damaged than anything else. I know it's on the driver's side, but you never know.

 

Also, if it's not, hit me up and I'll do my best to help you out! Take care

 

Thanks man!!!

I will keep an eye on it and refill it every morning to see if the coolant stabilizes!! If on Sunday still dripping I will go under the car to see things closer

Also, if I am not mistaken, the water pump pipe just has an O-ring at the pump end… I found it here https://www.northamericanmotoring.co...html?styleid=7
Comments #6 and #7

hehehe I know I sound like I want that to be it haha but seriously Im going to think that is just coolant leftovers until I go under the car this Sunday!!!
At least Im gonna sleep tight for the rest of the week!

Thanks!!!!

 

It seems like is not leftovers, I have been checking the level up during the past 2 weeks and is still leaking on the passenger side. Near to the wheel and around 20" from the front.

I went under the car last weekend but no luck. I could not detect the leak. Next sunday I am going to be putting the car on proper jack stands and take a deep look.

Any suggestions of where to look at? at that side of the engine is just the water pump right? Is there any more houses that might be faulty? I still think that might be that I dislodged the pipe that connects the WP with the Thermostat, any suggestions of how would you check that?

I took some pics of what i could see from under, just in case you see more than me

Thanks,
Pepe

 

You can buy a coolant dye kit from auto parts store with glasses and black light flashlight, which helps detect the location of the leak. After I replaced my thermostat housing it turned out to be the seal in the oil filter housing. There is a water passage that helps cool the oil.
Good luck , hope it's just something simple.

 

Hopefully it's just leftovers; there are lots of spots for the coolant to pool on top there. If it's not, my guess is that the housing isn't plugged in all the way in the back to the pump.

If it isn't those things, maybe a water pump is bad. That's kind of a known issue too, and it almost sounds like that's the area under the car where you're finding coolant.

Hopefully it's not that, and make sure you post an update, good luck!

 

Ok! I just purchased the R56 09' S! with 30,000 miles...So I do all my wrk myself
New to the Mini..What would all you say as preventative measures is the best time to change this Thermo housing? I don't want to wait till it goes or leaks!
I'm thinking its about due to be swapped out. Coming from the Audi TT and that was the water pump and timing belt changed every 60,000 miles which I changed out three times..PITA but saved well over a Grand on repair each time...
With that being said Miles wise best time to change this thermo housing?
Thanx!

 

Mine failed due to the thermostat being stuck open and it threw a code. I also had a very minor bit of seeping at the temperature sensor.
If the thermostat housing or gasket fails and starts to leak, you will notice a slow decrease in coolant level at the recovery tank. I don't believe anybody has reported a catastrophic failure of the thermostat housing with immediate total loss of coolant.
Your thermostat may last the life of the car. My advice would be only to replace it if it starts to leak and you are sure it is coming from the thermostat.

 

I'm replacing mine today on an R56 (non S). Thanks all for the great info, pics and tips.

One question:

When unplugging the dual pin connector for the oil pressure switch (on the side of the cylinder head), it appeared to only have 1 grey wire coming out of the wiring harness and entering the connector.

The other connector pin has a stub of a green wire but there's no green wire coming out of the wire harness. I cut back the braided nylon sheathing about 3" but found no adjacent green wire (thinking it may have broken at the connector some how).

Does this oil pressure switch connector only use 1 grey wire?

Hoping to avoid a CEL when restarting. Thanks!

 

Ditto – I too have a few notes to add to the many good ones already in this thread, in hopes they'll save someone else time and pain.

I specifically recommend this really thorough write-up of the process:

MINI R56 Thermostat Housing Replacement – by Juan Jose Chong

I did as well. I ended up buying a hose clamp tool at my FLAPS (Friendly Local Auto Parts Store), it helped but was actually too large for a the smallest of the hoses.

I replaced most of the BMW hose clamps with stainless worm-drive clamps that can be loosened or tightened with just a 10mm socket or screwdriver. This paid off almost immediately, as I'll detail below.


Me too. Here are the ones I actually think need to be unplugged:

• Temperature sensor (top of housing)
• Thermostat heater (bottom-rear of housing)
• MAF sensor (driver's side of air box) (for left-hand drive cars)
• Turbo/intake plug (no idea what it does)

I do recommend labeling them; masking tape and a marker worked for me.

I followed instructions that recommended disconnecting every part of the wiring harness possible and removing the plastic guide channel. In retrospect, that was unnecessary and created a lot of extra work I didn't need to do. (Plus I broke most of the tabs holding the top and bottom of the channel together; zip ties to the rescue.) All you need to do is pull it straight up off the mounting tab; that gives you enough room to get a socket underneath to remove the uppermost bolt of the thermostat housing.

I bought mine at my local dealer. I had ordered some other parts from their website (unrelated project) and they had screwed up the order, so as an apology for that, they gave me the online price on my thermostat & coolant and I paid about $130.

My Other Screwups and Lessons Learned:

• The water pipe at the bottom of the thermostat has a notch and the thermostat has a tab. Get them lined up perfectly to ensure a tight connection. I didn't, and lost half my replacement coolant there. An avoidable mistake. This is how I got extra practice removing and reinstalling all the electrical connectors, hoses, clamps and bolts. Had I not already replaced most of the spring clamps with worm-drive clamps, I would have sat down and cried at that point. Those worm-drive clamps saved my sanity.
• It's easier to line up and connect said water pipe to the bottom of the thermostat housing if you remove the air box.
• If you have trouble getting at the bolts, practice lining up your tool using the replacement thermostat. Teach your hands how it should feel; this makes going after those blind bolts much easier.
• When you add coolant, use a screwdriver to loosen the vent on top of the thermostat. This step is not mentioned in the Bentley manual and makes bleeding the air about a thousand times faster. Don't forget to tighten it when done.
• Have a magnet on a stick on hand. I've got a 10mm socket stuck somewhere down under the ECU.
• Clean up the thermostat mating surface on the engine block. Hey, you're already in there… might as well ensure a good seal.

A few pics:

• Engine Codes: P0118 and P15E9
• Alarmingly high temperature reading
• Jacked up at all 4 corners to ensure proper coolant drain
• The new Jarvik 7
• Label all the electrical connectors (one I labeled "engine mystery")
• After the repair, very reasonable thermostat temperature a few minutes after a cold start (after driving a bit it came up to a proper ~180-220ºF where it should be)

All in all I spent way too much time; the learning curve was much steeper than I expected (or should have been—thermostats aren't rocket science!). Now that I've done it, I think I could do it again in about an hour.

Hope this helps someone else.

 

My thermostat housing just went the other day as i did see inconsistent pooling on my garage floor and on top of the transmission housing. I did follow the following youtube video who used a gopro that was forehead mounted. In the video the author did not remove the entire air box so I removed the entire airbox to get a better look at the rear pipe when looking attaching the clip to the rear pipe. The rest of the video was spot on an well put together. The failure on my pipe was a crack on the rear top pipe that caused a leak, I did not receive a check engine light for a thermostat failure. I attached a picture with the failed pipe on the left. The old housing was made on 1/2008 and new housing was made on 1/2014, they look exactly the same visually. Took a couple hours to complete the change, I used Zerex G-05 coolant purchased from Pepboys for $15 and the Thermostat housing I purchased locally from Braman Mini Palm Beach for $121. Enjoy

 

Failure at 98,000 miles actually in comparison to my Audi TT that's pretty damn good.
The TT I had to change the Water Pump every 60,000 which was a pain in the bottom!
and was twice the work you did and its tedious as I can see on the Mini as well. Well done for a DIY. Thanx.
When time comes for my change out I will refer to this, Awesome!

 

I'm at 54k and my thermostat has started leaking. I'm the second owner so not sure if the first previous owner had replaced it before. Do I need to buy the new sensor as well for the install? The car never threw a code, it's just leaking.