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

 

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.

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.

 

Personally I could not tell which one it was (the filter housing or the thermostat) when it was on the car. I gambled knowing the thermostat has a high rate of failure/leakage.

Once removed, it appears that mine was either seeping from under the gasket or (more likely) was seeping out of the top through the temp sensor....or both. There were signs of coolant on top and around the area of the sensor, so that's probably the area.....you can't really see the sensor very well until the housing is removed or things are moved out of the way. My thermostat housing was not cracked, btw.

After doing the thermostat replacement, no more leaks for me.

 

Mine wasn't cracked. I think its was the housing gasket that was faulty. From what you are saying. It sounds like the thermostat housing. I could not find anything wet on any of the pipes either yet there would be puddle and dripping towards the back of the engine. The new housing has 2years or (xxxmiles forgot the number of miles) warranty. I hope it lasts longer than that.

 

I finally did the Thermostat housing swap. I was surprised about how it was easier than expected. Thanks to all the help on here. I would certainly rather do that than some of the other stuff I did on my own.

I was able to remove the housing and extract it with no movement of the wiring harness, itself. I did pull off the vacuum line to wastegate for a little extra room. This frees the harness carrier to slide vertical about 1 inch. I torqued the 3 bolts to 70 in/lb. on reinstall. I guess 3 hrs taking my time.

I changed the oil at same time, since I was right there, making a mess, anyway.

It looks to me that the root cause is the rubber gasket itself that seals the housing to the block. It was flat and had no life. It would be interesting to see what a tightening of bolts would do, if you had a leak, as it might just seal itself? I have 47K mi so now that i know what is going on, if I have a future issue might see how snug they are. They came right loose with a 1/4 drive small ratchet. The housing itself looks perfectly fine. Maybe a gasket and a thermostat would be good to go?

Another marginal part by BMW/Mini. Thanks for all the advice.

 

I use Amsoil's coolant http://www.amsoil.com/shop/by-produc...lant/?=2056145

 

This is a great thread , if it was not so cold out and dark when I get home from work , I may have attempted this myself .
My check engine light came on last week error code P112B on my R56 2007 S 53,000 miles . It turns out I have a coolant leak . I just had my local mechanic ( Bergen County NJ ) replace the thermostat housing ( jarvick 8 )
This is a very common failure , he said if you have a leak this is most likely the place, with 8 hoses going to it . Just for a price comparison he charged $114.58 for the the thermostat housing , 3.5 hours labor ($75) $262.50 , $23.80 Cooper Anti Freeze . Total $400.88 . So if you do it yourself you can save a couple of Benjamen's .

 

Did you ever dig up the outfit where you purchased the housing? It looks like it's my turn in the barrel.

 

Parts.com
$75.11+SH

 

I looked at parts.com and it looks to me that it's a junkyard part for about $90 shipped. They say it's "remanufactured" and the "catalog" it came from was called "collision catalog". This translates to me as a junkyard pull that got wiped off with a new shoprag. I ended up ordering an OEM part from www.oembimmerparts.com for $105 shipped.

 

The one I got was brand new from them. Here is new on left, old on right. Anywhere near $100 seems reasonable.

 

Thanks to everyone who contributed to this thread. I completed my thermostat replacement and have been driving my Mini for a few days with no problems.

I appreciate all the help and tips!