HOW TO: R56 - Thermostat Housing + Thermostat
 

So I guess things fail in pairs. last week my water pump went out, this week the thermostat housing started to leak. Unfortunately MINI uses plastic parts yet again.. and they heat up and expand and leak, kinda irritates me. I have 59k miles, water pump started leaking at 53k.

The white residue in the picture is where I was leaking from.

Attachment 170451



Again, I refuse to have MINI work on my car cause its over priced and I like to save money.

I bought the thermostat, which has an integrated housing and sensors. Cost was $111.67 and a gallon of MINI coolant - 29.12 so roughly $150 out the door with tax.

Tools needed - BEER, Flat head, 10MM socket, Extension, and pliers.

Thermostat housing:

Attachment 170452

1. I disconnected my battery.

2. Removed my Alta Turbo Inlet Pipe and Maf. - Used a flathead.

Attachment 170453

3. Remove the fresh air pipe that runs off the head light.

Attachment 170454

4. I disconnected the Vacuum line off the Wastegate and the other one that runs to a nipple near the wastegate.

5. I did my best to move the ECU wiring harness out of the way.

Attachment 170455

6. I unplugged all the surrounding sensors, including the sensor on the ABS unit.

Attachment 170456

7. I started removing houses one by one off the thermostat.

8. I removed the clip that is located under intake manifold that connects the housing to another water pipe.

9. I removed the 3 10mm bolts that hold the thermostat housing to the block.

10. I then reinstalled in reverse order.

11. Added coolant and bled the system using the flat head and the bleeder valve on the top of the thermostat housing.

Thats about it, it took under an hour to do myself. I used literally 3 tools though, it was simple and straight forward. I have saved roughly $500 just in labor doing this all myself.

Thank you

If anyone has questions please pm me.

Nice work lad :thumbsup: .

Hate to say it
 

But one of your hoses is likely to go next. I reccommend squeezing them all. Any that feel soft are about to go. Since the plastic impeller on the pump and plastic housing of the thermostat both failed I assume you have a lot of miles on your car. That means all those coolant hoses have seen the same high number of heat cycles. The best way to address this is to do it all together. Then you wouldn't have to buy 3 gallons of coolant. Though honestly you can reuse the coolant as long as you filter it if any dirt gets in while draining.

I have 59k miles on my car.. I dont consider that a lot?

We have done a few R56 thermostats here at the shop and have nicknamed the thermostat the Jarvik 7 cause it looks like an artificial heart from the 80s.:lol:

:lol: :lol: :thumbsup:

I don't think the deteriorization of you car's coolant hoses cares what you think is high mileage or not. But don't blame me when in 10or 20k miles your hoses start failing one after the other.

Thanks for the post
 

I'll be doing this soon on my 07. The dealer wanted $570 for the repair and I just can't bring myself to pay that. I've got 29k miles and am a bit disappointed in the failure in what I still consider a young car. Oh well, my hands have been clean for a couple months and that's far too long :)

-JL

Waaaaayy nice work. You make it look so easy.

Hey does anyone make a billet thermostat housing??? That'd be nice.

A couple more notes on this changeout
 

The repair took me about 2 hours. See the attached pic, but when reattaching the large radaitor coolant lines (the ones facing the front of the car), you need to 'clock' them so they stand up above the shifter linkage (at least on manual trans cars). Otherwise the shifter linkage hits these coolant lines and a failed hose will not be far behind.

Side notes:
1. I cleaned up some of the rough edges on the coolant passages inside the housing.
2. I was running water wetter in the cooling system before the failure and decided to use it again.
3. I ordered the part from a place in Florida and will post the link when I get a chance. They sold me the part for just under 100 bucks and were great to work with. https://www.koperformance.com/
4. Total 50% coolant needed for refill of the system was ~3 liters.

-JL

What's the secret to getting the ECU wiring harness cover off? Thanks!

Just did this myself. To flesh out some things that I would add as someone who hasn't done this serious a job on a MINI before (and to answer a question above):

1) The ECU harness cover is clipped on with lots of plastic clips. With these, as well as the sensors, etc., I found that dental pick was a great tool to hold down the keepers and pull off the connection. The hardest were the two round pegs that go from the wire cover to the top of the thermostat. It took some fiddling to get them to release, especially since you can't see underneath. I had to use my dental pick and some pulling and swearing.

2) For those of us without the Alta mods, the equivalent is removing the air intake and the filter box. Just takes a few screws and the box pulls out of its rubber mounts.

3) Note that the clip on the thermostat housing that goes into the tube on the back of the engine (under where the filter box goes) is a V shape. Just pull up on it with the pliers and it will pull right out.

4) If you don't have the special tool for the hose clamps a small pair of pliers with an angled head (like small water pipe pliers) comes in really handy.

5) Of course, you should drain the coolant before you do anything else. I found the best place is just under the front of the car where two hoses join.

Good How-to. Does anyone know what's different on "justa" R56?

I just did the thermostat replacement last night and would like to add my notes...

I had a very difficult time getting the hose clamps off. If you don't have the appropriate tool to remove the clamps, do yourself a favor and buy the tool. I don't know what tool it is, but I just used an old pair of pliers and I caused myself way too much grief. The majority of my time was wasted monkeying with those stupid clamps.

The difficulty with the pliers pushed me to probably unplug too much of the wiring harness. As I looked at the plugs, I noticed they were all various sizes with different length wires. I thought it would be easy to plug them back in the right spots. WRONG! I did fine up until the branch of three plugs towards the front - the set that includes the one plug that connects to the temp sensor. All three of those plugs look the same, but are color coded. I plugged them back in according to their colors. WRONG! After driving around a bit, I got a check engine light. Autozone was unable to make the CEL go away, so I limped to the mini dealership this morning (in engine protection mode). After paying the $119 diagnostic fee, they said it looked like I did a great job replacing the thermostat but simply flipped two connectors. The technician told the service adviser "it looks like he connected them according to their colors, which makes sense, but they don't connect like that." What colors go where? I don't know, but pay attention to which plug goes where and mark them with tape until you get them reconnected.

This isn't really mentioned anywhere in this thread, but as a side note, 99.9% of the work you'll be doing is done from above the engine, not below the car. The only thing you need to do below the car is disconnect the coolant hose at the splice connector to drain the old coolant.

I bought the thermostat from MINI, along with a jug of their coolant. Total was $165 out the door.

Anyway, I wouldn't classify this as an easy repair, but it was nice saving roughly $500 for about 5 hours of work. I'm sure it would take less time had I used the proper clamp tool. I only wish I'd paid more attention to the plugs, which reduced my $500 savings to $380.

The dealership said they see 2-3 of these thermostat replacements come through the shop every week. Being so common, it would be great if someone could shoot a video of the process...

Mine was replaced at 26k along with the water pump

Anyone use coolant other than the "Mini" coolant? I can't imagine Mini has some secret formula to coolant.

What is the best tool to remove the MINI hose clamps? I want to get ready to do this replacement and don't want busted knuckles or broken parts.

I just did the repair last night in about 3 hours. I just placed cat litter under the car to catch the coolant and replaced what was necessary. I agree with everyone above, the hardest part about this job is probably dealing with the hose clamps. I didn't have the tool to remove the clamps, but I fared just fine with a pair of pliers. I also found that it's important to remove the hoses in a certain order since it'll make removing the part much easier.

I removed the two large hoses in the front (side closest to the front of the car) first, then the two larger hoses behind the part. I then removed the bolts to the part and began wrestling it out once I disconnected the tube that runs behind the engine. Once everything was loose (except for the small hose at the front of the part), I wrestled the part out while moving the clamp out of the way and pulled the part free from that last tube.

I installed in reverse order and everything worked out well. I also found that it helps to have a thin wall 10 mm socket. Don't connect any hoses except for the small one on the front of the part before bolting on the part. It makes working your socket into the part much easier.

Good luck!

Thank you!
 

This how-to saved me almost $300. Thank you so much! It really wasn't a very hard job to do at all. A certified MINI mechanic said he doesn't even like doing the 2nd gens bc of how hard they are. I had everything off in about 45 minutes including 15 mins for a broken hose clamp.:thumbsup:

Glad I could help people, it really is very easy to do.

93k miles now never had a hose issue. weird.

I sprang a leak today. Lucky for me I saw it as I backed out of the driveway and didn't drive off. So I jacked the car and could not really tell where it was coming from seems like from the thermostat area. So thank God I found this thread. Got my S40 put back together just in time for the R56 to take a crap, yeah.

Nice thread... I will be referring back to this thread when I receive my new Thermostat from ECS Tuning later this week. I have 46K miles on a 2008 MCS. Thermostat should last longer than this, especially sionce they cost $100! The thermostat on my mini van was $10 and extremely easy to replace.

Received and install my new thermostat yesterday. Took longer to take it all apart and remove the old one, than it did to install the new one. Use the top of a bin lid to catch the antifreeze run off. Total of just under 3 hours. Refill antifreeze and use the bleeder value to insure the system was full of fluid.

That was a PITA...and now I get the large half MIL light on my tach and the car produces only about 3-5 PSI of boost. I'll figure out what's wrong with it tomorrow, or try anyway, too tired to even THINK about troubleshooting tonight.

update:confused:

I am about to swap out the thermostat on my 2007 MCS. Thanks so much for the info.
Does anybody know the torque specifications for putting in the 10 mm bolts that hold the housing?
Thanks

thank you for the points. Can you please explain a bit more on removing the ecu wiring. I see a housing and a bunch of clips. So do I just unclip them? I am asking as i am not getting a sense of direction on how to remove and how many wires to remove. If you can give a bit more details that will help me a lot. I will be attempting that soon.
thanks

First, thanks to the OP who posted this. Very helpful. Just finished doing the job on my MCS this morning and all is good. Not necessarily a hard job, just a PITA.

@ sripavan: The wiring harness is covered with a plastic cover that has about 8 or 10 little clips holding it on. Honestly, I broke a few of them, but it clips back on and stays even if you break a few of them. The plastic it is made from is pretty brittle....it's there just to shield the wires from damage. In all, I think I unplugged 4 or 5 sensor plugs (including the two on the thermostat housing). There are two on the tube from the airbox to the turbo that need to be unplugged to get that hose off (on the MCS). There was another that I do not recall which one it was and then the two on the thermostat. I would suggest that you label each of them as you remove them (I used masking tape and a sharpie) so that they can all go back on in the correct place.

Once you remove the cover from the wiring harness, you will need to clip/cut 3 or 4 zip ties holding the wires into the "channel". After doing that, you can pull all the wires out (they stay pretty much together as a unit and just lift out. Once the wires are out of the way, the whole "channel" or harness holder lifts up. There are two little round feet that "plug" into the top of the thermostat housing and one slot that clips onto the engine lift point at the top. You'll have to release that clip to lift the "channel" out from under the wires.

It sounds complicated, but it's not. You'll figure it out.

One tip that I will add to this DIY is to feed the replacement zip ties through the wire "channel" before putting it back on the car. I didn't do that, but was able to feed two or three ties in which was enough to hold the harness firmly. Just something I would probably do differently next time....but there better not be a next time!!!!

thanks a lot for the details fastlane. I started breaking a bunch of those tabs so decided to leave them as is and just move the housing up and down as needed. Your reply adds a lot of clarification.

other than that I ran into 2 more problems.
1) the small pipe that goes to the turbo charger, seems to be held by 2 clamps. Do I need to remove both?
2) the large hose that is in the back attaching to another hose beside the intake main fold was very hard for me to remove. I was able to lift the clamp partially away. However I think the bottom half of it was still inside the slot holding the pipe. Any idea on how to proceed.

thanks a lot in advance.

The small pipe you refer to must be the PCV....it goes from the crankcase on the drivers side into the turbo intake pipe just as it enters the turbo. I left it attached to the larger hose and just removed the clip on the crankcase that holds it in. Just use a screwdriver and gently pry both sides of the clip up from the bottom and it comes off....and then the hose easily just pulls off from the crankcase. Then remove the large and small hose together as one piece.

The other pipe you speak of is the air supply tube that draws air in from a hole near the headlight. Once you disassemble the air box and loosen the lower portion and pull it up, you can use a screwdriver and pry the sections apart and pull them out. There are four tabs around the inside of the tube that lock it together. Just jam the screwdriver in there and pry in a couple of places and do lots of wiggling and pulling....your not likely to hurt this pipe too much. After the air box and the back half is out, pull the front half from the collar at the headlight and pull the other part of the tube out.

Be aware that the brake booster vacuum tube is attached to the air supply tube with a little clip near the airbox. You will need to unclip it before taking the large tube out. Also, I unhooked this vacuum line at the top of the engine and folded it out of the way during the repair. Just press the clip and pull up. This tube is the thin one that is on top of everything else on the engine once its all assembled.

Hope that helps.

sorry I was talking about the tubes that come from the thermostat housing. The very small tube in the front and the large one in the back that attaches to another tube.
Sorry if I wasn't clear.
thank you.

Oh, o.k....sorry about that. I misunderstood you. I undertand now.

When i did mine, I removed all of the hoses except for the two that you are talking about. At that point, I pulled the clip from the rear tube (it pulls straight up, not back and up like you would think....so pull it kind of up and towards the engine/intake and it will come out all the way...use pliers). then, loosen pull the hos clamp on the end of the short hose that goes to the turbo on the thermostat side only....leave the hose attached to the turbo. Then, remove the three bolts holding the thermostat on and start wiggling. The pipe will come detached from the back and pull out and the hose going to the turbo will start to come off. From there, you should be good to go. When putting on the new thermostat, put the little turbo hose on on first and then push the pipe on in the back and start putting it all back together in reverse order. Tightening the thermostat bolts will draw the two rear rigid pipes together and you can then put the clip/pin back in.

As someone mentioned above, make sure the two hoses that cross over the transmission clear the shift linkage if you have a manual....otherwise you will saw right through a hose when you shift and that would be bad. :eek:

I've had to bleed the system fo air a few times recently and have gotten pretty good at it....what I do is (as recommended) turn the car on (not started), se the heat to high temp/low fan, and start pouring in coolant. Fill slowly until the level no longer drops. Then start the car and let run....fill as the level drops. When it levels off, put the cap on and let the car warm up. If the level drops too much, shut off the car and let it cool down, then refill to the line....replace cap and start the car back up and warm up. Repeat as needed. Then to bleed, when the car has warmed up, shut it off and let it sit for a few minutes....take a long flat blade screwdriver and turn the bleed screw (on the top of the thermostat) until either air or coolant escapes. You will need to turn the screw about three revolutions before it opens....don't turn it much past that, though, or the screw will fall out.....that would be bad.

I usually carry the screwdriver with me for a day or two so that I can bleed off the air after reaching my destination....two or three times and you will get all the air out and you will be good to go.

BTW - Merry Christmas!

thank you so much for your time and writeup. I will attempt it again soon.
merry Christmas to you as well.

just wanted to add a small tip. While drainnig coolant, loosen the bleeder screw. Most of the coolant will then come out of the drain tubes at the bottom. Later when you start removing the hoses from thermostat housing there won't be a lot of fluid coming out.

I have a coolant leak, and am having a hard time determining if it is leaking from oil filter housing or from thermostat housing? The coolant is on top of transmission and mostly drips off the rear of the trans housing. My R56 has 47K. Thanks for any suggestions.

In my case(which is a leak from the thermostat housing) I had puddle arround the same area. I wasn't sure if it was one of the pipes carrying coolant into thermostat. Hence took it to the dealer who is about 30 mins drive and after determining its the thermostat housing, bought the part from him. He charged me around $50-$60 for diagnosis. But that gave me assurance what was causing the leak. Of course be sure to fill in coolant before taking it to the dealer.

Mine was the thermostat and happened right after my water pump replacement just like you. Actually, they were probably both leaking at the same time and I just didn't realize it. I agree the leak was hard to track down....same place as yours. With the thermostat being plastic (and seem to have a high rate of failure/leakage), it's more than likely the culprit.

When I get home from work today, I'll find the place where I bought it and post. I found a good deal on one....around $80 shipped as I recall.

BTW, it was much easier to replace than the water pump....definitely a DIY job. Still a bit of a pain because of having to move wires out of the way, but still not terribly difficult.

I am going to take another good look at it this weekend, see if I can positively identify the Thermostat housing as the leak source. It does seem to be more towards the reear of engine. When you pulled the housing off, can you see it as cracked? I am sure that none of the hoses are leaking. I ran my hands over all of them and found no wet areas.