Water Pump DIY on BMW 535i LCI

While driving home yellow warning light lit up  - “engine hot” –  recommending me to slow down and take it easy. I was going 35mph … Also, the air coming from the vents was ice cold… classic symptoms of water pump failure.

Symptoms:

1. The fan is always ON and at maximum speed

2. No heat inside

3. After 3 miles of driving “engine running hot” warning comes up.

4. NO CEL!!!! Surprisingly no check engine light, the only code present 0x2E82 and it does not trigger CEL!

5. Pump priming procedure results showed failed water pump (listen to audio clip).

 

Diagnostics.

First thing I noticed that the fan was on “HIGH” and the car sounded as an airplane ready to take off. It did not make sense as it was 15F outside, the fan was always on “high”,  I was driving slowly.

I checked the codes. Sure enough there was one sitting – 11906 (or 0x 2E82 hex) which did not trigger CEL. The actual code is for defective wire harness between the pump and DME.

I did not know it but it looks like BMW has a very high rate of water pump failures on n54 engines. BMW dealership confirmed that water pumps fail as early as 20,000 miles! The same was confirmed by indie mechanic – the most popular repair in his shop is water cooling system failure…. He was very knowledgeable about the problem on n54. Both recommended to replace the water pump together with a thermostat. 

As far as cost you can expect to pay $1300 to $1700 for this job at the dealership depending on hourly rate. It is considered 4 hour job which I find unrealistic – if you know what are doing it is 3 hours maximum. I am not a mechanic and I changed the pump together with thermostat in 5 hours (and that is just because I took pictures, had coffee brakes, waited for the coolant to drain etc). The most time consuming is lifting the car, preparing tools, cleaning up etc. Also, it was first time I worked on e60 (I did some work on my previous e46). The hardest part is lack of space – other than that it is easy.

Parts. 

I chose to go OEM parts route. With this particular engine (n54) there are not many aftermarket parts options. Dealership wanted MSRP + tax and it was over $800 just for the parts. After some research online found out that the same OEM parts can be ordered with 30% discount from by www.tomkinsonbmwparts.com.  Considering MSRP 30% discount represented substantial savings.

shopping cart

 Water pump. As of today (01.2013) BMW is on a 3rd generation of the water pump (for n54). The newest part number is 11 51 7 632 426. The pump I received had Continental logos all over it. The older design pump was made by Siemens VDO.

water pump water pump front

MSRP: $624.13 (bought for $436.89 at TomkinsonBMWParts.com)

Bolts.

N54 engine block is aluminum and BMW also uses aluminum bolts so the old ones can not be reused. On top of that BMW changed the design and old bolts do not fit – they are just too long. Correct bolts # 11 51 7 602 123 (must be used with updated water pump as they are shorter). New bolts are not Aluminum! Old bolts #11 51 0 392 553 come as a package of 3  and they cannot be used with new design. Be aware.

New and Old screw

MSRP: $1.29 each (3 needed)

 

Thermostat. The part number is # 11 53 7 549 476. It is not required to change while changing the pump but as I am spending 4 hours on the pump, mind as well change it.

Thermostat pic

MSRP: $114.58 (paid $85.94 at TomkinsonBMWParts.com)

Coolant. Just buy it from the dealership as shipping from online vendor does not make sense – shipping charges will be ridiculous. At your local grocery store buy a gallon of distilled water as well – you will need to mix it with coolant later.

Preparation and removal.

For this job you will need lots of extensions. The more the better as the space to reach the bolts is quite limited. It is not as bad as I imagined, but still tight. This DIY is made assuming you will change the pump at home (or garage without hydraulic car lift). My car is 2008.06 535i LCI N54 engine. I don’t know how different it is from preLCI, but hoses and chassis is different than 3 series (e90/e92)

You will need:

6mm socket

8mm socket

10mm socket

13mm socket (regular and deep)

Torx e12 socket (It might be hard to find it as not many part stores carry it and I had to buy a kit – $15)

wrenches for sockets (1/4 and 3/8)

extensions

universal joint set (Strongly recommended)

screw driver (phillips and flat)

container to catch the coolant

container to mix the coolant with water

lots of towels

ramps

good quality jack

portable light(s)

1. Get you car on ramps. Mine has MTech front bumper and it is too low to drive on my low profile ramps. Solution – lift one side with a jack, put the ramp under the wheel and lower the car. I found that  if I have both front wheels on the ramps there is not enough clearance for me to work under the car so you might have to get a little bit creative or take some risks to lift your car higher (especially when you lower the steering rack). (5 to 20 minutes)

2. Disconnect the battery. It is located in the trunk on the passenger side. Remove the panel (just two plastic tabs) and wiggle the panel out. I used 13mm socket to disconnect the red wire. Make sure you don’t touch any metal body surface. Secure the wire that it would not touch the positive battery (I used clean towels to cover battery terminal) (10minutes)

3. Remove the splash guard. It is being hold with two 13mm bolts toward the rear and 6 screws on the sides. (5 minutes)

4. Remove the power steering rack. Driver side is easy – bottom is secured with 13mm washer, top with 13mm bolt. Passenger side the top bolt will be harder to reach but with right extension will be easy. After removing bolts disconnect the vacuum tube (it looks like a wire splitting into two). I found that it disconnects fairly easy – pry it a little bit with a screwdriver. Then pull the rack toward the front and let it hang. I did not hang it on anything. (assuming you have no other wires). (10-20 minutes)

steering rack

power steering vacuum copy

5. The fun part begins here. I would recommend to observe all the hoses and clamps. Take the new water pump and thermostat and look how everything is put together. Some of the bolts are not visible at this point. Make sure the car is cold as at some point the coolant will have to be drained. (30+ minutes)

5a. Thermostat. In order to remove the water pump thermostat has to go out first. Thermostat has 4 hoses – two of them are tightened with clamps (towards the rear of the car) and the front two with clips (plastic ends). Thermostat is bolted to the water pump with 2 10mm bolts and connected with one wire. Also, to gain more room, you will need to remove the splash guard (plastic) – there is only one 8mm screw inside the wheel arc. I’ve started working from the front. Remove both clips from the hoses (or push them up with a flat screwdriver. The bigger one was stuck so I had to wiggle it with some force. The smaller one disconnected very easy. Have a container ready (I used my oil changing pan) to collect the coolant. It will splash (Video link) after you will disconnect the hose . (I’ve used plastic water bottle with cut off bottom to catch the coolant). After the coolant stops clean up a little bit – dripping coolant on your face is not fun. After clean up I unbolted the thermostat from the water pump as I could not get to one of the hoses. The rear ones are a little bit harder to disconnect as there is not much space.  I had to use  extensions with universal joint to reach the 6mm bolts. Remove the thermostat. It should come out easy.

Thermostat Thermostat hoses

Tip: Put some paper towels into the coolant hoses because dripping will never end (at least it feel like it). You might have to change a few towels till there will be no more dripping.

5b. Water pump. It is bolted to the block with 3 torx bolts. Water pumps has two hoses and both are PITA to disconnect due to lack of space. First, I unscrewed both 6mm clamp bolts. You will have to get creative here as screwdriver might not fit. Next, I unbolted Torx bolts. Bottom ones are clearly visible but the top one is … not. First, move you head toward the passenger wheel in order to see what is on top of the pump. The bolt is hiding under the wire harness which you will have to disconnect from the pump. After you take the wire out of the clip, unscrew the bolt. The pump is now held only with two hoses which can be pried off with a screwdriver and wiggling the pump. Remove the pump after you disconnect the hoses.

6. Put everything back together in reverse order. (45 minutes)

6a. Water pump. It was a lot quicker to put everything back – I was done in half an hour. For the water pump, put the wire harness clip from the old one. Put the water pump into its place: connect the hoses first then tighten the clamps. Notice that if you have a new design pump it does not have rubber grommets – it bolts directly to the block. Put Torx bolts, torque to specification ?.

Old water pump

6b. Thermostat. First, put the hoses with clamps – one from water pump and another right next to it. Position clamps that it would be comfortable to reach with wrench and 6mm socket (of course, with extensions). Connect the hoses with plastic end and push clip back on. Make sure you have enough light to see if the hoses are pushed all the way in. Connect the wire, bolt it to the water pump.

Tip: Position the clamps that it would be easy to use the wrench with 6mm sockets as a screw driver was not working for me – not enough leverage to tighten the bolts.

6c. Coolant bleeding. Next step was to fill the system with coolant. I did not put the steering rack back on because I wanted to make sure I have no leaks. Procedure is straight forward – mix a gallon of BMW Coolant and a gallon of distilled water. Before you pour the coolant remove the bleeding cap (next to the fill up cap) on the coolant tank. Pour the coolant mix in – it took approximately 1.5 gallon of this mix till tank was full. Next turn the ignition on (without pressing the brakes) and hold gas pedal for approximately 10 seconds. You should hear the pump start priming. Add coolant as necessary. In a few minutes or so I added almost all coolant I had left – total of 2 gallons. Put the caps on and start the car. Run it for few minutes and check if you have any leaks. If not, stop the engine, top of the coolant if necessary. Compare working pump sound (15 minutes)

6d. Finish up. Put the rack back on, splash guard etc. (30 minutes)

Summary:

I don’t have a lot of experience working on cars. I did not consider this job to be difficult as it is straight forward. There are few DIY guides for e90 which might help you as well. As the engine is the same the water pump and thermostat are the same. Mounting and access to WP is a little bit different. Doing this job you will need some patience and creative extensions to reach some of the bolts. Make sure you have universal joint set or two as some of the bolts could be removed only using them. You will need Torx e12 socket as the engine bolts used by BMW require this socket.

 

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