Sunday, 12 October 2014

BMW E90 N46B20 Water Pump / Thermostat / Thermostat Housing

DIY Disclaimer: I hold no responsibility should anything goes wrong when you decided to follow my guide. It’s strictly meant as a reference for knowledge sharing purposes.

2007 BMW E90 N46B20

Mileage: 108k km

Been losing 500ml coolant weekly.

Photo taken from beneath the power steering pump.

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I have no idea where the leak came from due to limited visual access but I can confirm it is from one of the water pump components. And losing fluid at 500ml a week, I can’t be keep topping up and dilute my coolant mix which is not healthy for the engine.

So I decided to take the plunge by buying all the components for that location (just in case), including one of the short hose.

Item 1: Water pump: 11 517 511 221

Item 2: Thermostat: 11 537 510 959

Item 4: Thermostat Housing: 11 517 572 859:

Item 7: Connector: 11 517 542 128


.. and Item 1: Water Hose: 11 537 572 159


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The spark plugs are for different project. Smile with tongue out

The rubber O-ring came with the water pump are not utilized because the rectangle one already available in the new thermostat housing while the round shape O-rings are for the old connector which was designed differently. New connector as you can see from the photo above at 4 o’clock location is entirely coated with rubber.

Workshop guide:



1. Our E90 N46B20 power steering pulley actually do not have the 3 holes to reach for the 2 water pump fastening bolts. Hence the only way is to remove the power steering pulley. Slacken the 3 x T40 bolts on the power steering pulley before remove the V-belt. The tension provided by the belt help securing the pulley from spinning freely. The pulley is very light and made of plastic material.

2. Use a size 16mm wrench to tension up the V-belt tensioner and release the V-belt.

3. Remove the power steering pulley.

4. Slacken the 2 x T40 bolts fastening the water pump to the power steering pump. These bolts are very tight. My Torx key set failed me because it bent when I apply force:


I had to order this:


5. Now the tricky part. The 4 x T45 bolts is hard to reach. Luckily they are not extremely tight compared to the above. The “L” shape Torx key excels. The T45 bits I bought is mostly hopeless here due to the narrow access.

Below is how I slacken (NOT RELEASE) the T45 bolts and if you are confident, you can release the water hose connections as it will give you a bit of extra room:


6. Water hose disconnection. Start from the top. Lift up the metal clip (refer bottom picture, from point A to point B) and wiggle your way out, 3 hoses connected to the thermostat.


7. Disconnect the thermostat wire located at the bottom of the thermostat.

Got the following from Pelicanparts. Similar connector. Just press the metal clip to the green arrow’s direction and pull the plug off.

pic10.jpg (1536×1047)

8. Now you can release the 4 x T45 bolts. The water pump connector may still be hanging to the engine and require some prying to get it out.


9. After both the power steering pump and water pump is out, then only I remove the 2 x T40 that fasten the power steering pump and water pump together. Water pump can then be taken out. Viola!


Removal took less than 45 minutes. Installation is not easy. Remember to fasten both power steering pump and water pump together before attempting the 4 x T45 power steering pump mount. Do not forget the connector at the water pump. Very tricky to put it back in because it keeps jumping out.

All in, I spent 4.5 hours to complete the job, inclusive of beer break in between.. Started 8:30pm, completes 1am.

More photos for references:

Power steering plastic pulley can be open using the T40 Torx key. Notice the V-belt still in place.

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After taken out the water pump:

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Check out the thermostat top water hose. Size 10mm bolt. Also you will notice the water pump connector below the exhaust manifold.. took me a while to get it out. Actually mustn’t apply force as it gets tighter. Just need to repeatedly tap it to get it out. Ya, I replace the connector too.

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The old water hose, lucky I replaced it. Ya, I applied gasket maker here too :

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Another view at the stubborn connector:

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Bottom view:

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Back view:

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Check out all the screws and bolts taken out. How do you like my metal screw pan? I believe we bought it from IKEA toy section when my children were young. It was on the way out to the donation bin when I rescued it and turn it into a screw pan by adding few magnets at the bottom. Viola! No more losing screws.. Smile with tongue out

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Old versus new. I apply gasket maker whenever possible. In fact, I’m suspecting my leaks are from these areas and not the water pump.

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This is how I open the thermostat, using a 1/4” bit. 7 of these screws. 3 to secure the thermostat to it upper housing and 4 to secure the water pump.

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2 bottles of 1.5L coolant with 6L of distill water. Still plenty left.

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That’s all for now! Thank you for reading and please provide feedback or query if any.. Winking smile

Tuesday, 24 June 2014

BMW E90 Door window lifting mechanism rear

DIY Disclaimer: I hold no responsibility should anything goes wrong when you decided to follow my guide. It’s strictly meant as a reference for knowledge sharing purposes.

2007 BMW E90 N46B20

Mileage: 92k km

Door window lifting mechanism rear

Left: 51 35 7 140 589

Right: 51 35 7 140 589

My rear left lifter failed in Jun 2013 while my rear right lifter failed 3 nights ago.

Some call it Window Regulator, some call it Lifter. We seldom wind down our rear window and that’s where the problem lies. Over time, the window get stuck to the side rail and an attempt to wind it down will cause the plastic components to snap.

An irritating warning will light up on the dash board with a loud “gong” which repeats every 20 seconds. What it tried to tell is the anti-trap function deactivated:


This error can’t be reset or disabled until the lifter is replaced! Hence you will have to bear with the repetitive loud “gong” every 20 seconds.

I bought a replacement lifter and DIY the change.

These are what I did:

1. Open door card / panel as usual. Many guide available online and here’s one of the many, in fact this video is complete:

2. Carefully peel open the moist protector or damp guard layer.


3. Open the 3 size 10mm nut holding to the lifter.


4. Unlock the window glass from the lifter holder.

5. Unplug the motor connector.


6. Slide the lifter out.

7. Apply grease to the new lifter

8. Transfer the old motor to the new lifter

9. Reconnect the motor to slowly run the motor up/down to make sure the window glass holder slides smoothly, add grease when necessary

10. Disconnects the motor and slide the lift back into the door cavity

11. Reinstall the 3 size 10mm nuts

12. Reconnect motor

13. Make the window glass sit into the holder and make sure the lock is in place

14. Test the window, up / down. You may reprogram the window at this stage or may do it after reinstall the door card.

15. Installing the door panel:

~ Make sure all the upper metal clips are on the door and not on the panel. If any still stuck on the panel, pry them off and clip them back on the door before installing the panel. Easier that way.

~ Pay attention to these black color little fabric washer. It prevent noise from a loose stud. Some are stuck on the door and when you install the panel, it will just fall on the ground without you noticing it. Pry them off using you finger nail from the door and put them onto the door studs before installing the door panel. That way you will never lose them. Below photo shows only one of the stud with the fabric washer intact. The rest are still stuck on the door.


16. Reprogram the window:

Some material I found online..



New Lifter:


New vs old:


Thank you for reading and please provide feedback or query if any.. Winking smile

Saturday, 10 May 2014

BMW E90 DIY Rear Absorber Bump Stop / Damper

DIY Disclaimer: I hold no responsibility should anything goes wrong when you decided to follow my guide. It’s strictly meant as a reference for knowledge sharing purposes.

Been noticing my rear absorber central shaft exposed. The bump stop that’s suppose to hold on to the dust cover has disintegrated due to ageing. The dust cover is very crucial in protecting the absorber from grime and sand which get stuck onto the central shaft. The shaft slides up and down during operation and any dirt on the shaft will damage the oil seal in the absorber and causing it to leak.

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1. Open the left and right panel carpet in the trunk.

2. Open the rubber cover on top of the wheel well in the boot area and you will see the nut securing the absorber.

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3. Use a size 16mm ring offset spanner for the absorber nut while securing the central shaft with a hex bit wrench.

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4. Can safely remove all the nuts and washer and we can now slowly jack up the car.

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5. When the car raise, the wheel will drop and slowly widening wheel fender gap. As soon as you can reach your hands in comfortably, stop jacking and secure the vehicle whichever way you preferred. Slide down the absorber shaft and Voila! Bump stop and dust cover can be removed. From the photo below you will notice we do not even need to remove the wheels.

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6. Remove all the seats and washers. Refer to the red box below. Stack them together during installation. Only item 7 is installed from the top. Trust me, I learned the hard way.. Open-mouthed smile


7. Release the jack and fasten the top nut. Done! Now do the same to the other wheel.. Smile

2014-05-10 10.03.10


Similar procedure for rear absorber replacement:


Thank you for reading and please provide feedback or query if any.. Winking smile