I would be happy to assist you, do you possess the skills to perform this task and do you have the tools? Have you got the replacement parts yet? Did you get coolant? I am not trying to brow beat you, but unless you are able to answer yes to my questions, this will just be a typing exercise for me, and truthfully speaking, this is a job best left to a professional. I await your reply.
April, 23, 2008 AT 9:22 PM
Yes I have done a complete removal of the entire cooling system on my e39. I do have the tools and I do have the parts. I have the housing unit and the waterpump itself.
What I am unsure of is, unlike the E39, the radiator and fan are separate on the Z4.
April, 23, 2008 AT 9:33 PM
I understand your reluctance, fear not! Remove the fan/shroud as a unit and the repairs are very similar to the E-39 body style. Repost if needed, I will be standing by.
April, 24, 2008 AT 12:13 PM
I figured that out this morning, now the question is how do you remove the reservoir tank and I notice there is a metal bracket that is in front of the water pump housing unit.
Is that bracket attached to the front bumper and do I have to remove the bumper to take the bracket off?
April, 24, 2008 AT 8:15 PM
I am unsure why the expansion tank needs to come out for a water pump replacement. The technical service bulletin says the nut securing the left motor mount needs to be removed and the motor lifted 30cm to access the pump.
May, 25, 2008 AT 6:08 PM
I just tried to replace the water pump on my 2003 z4 2.5 (m54-e85) and it seems you do have to lift the engine 30cm by removing the driver side bolt on the motor mount. The sheet metal brace that holds the fan and radiator is part of the front clip. There is not enough room to slide the pump out of the engine block. It will hit the sheet metal brace. I do not have an engine hoist. So I have to pay someone else to do this.
May, 26, 2008 AT 6:16 PM
OK. Here is how you really change the water pump on a Z4.(E85, m54 motor, mine is a 2.5) I have done this procedure, and all you will need are one water pump with o-ring, two m6x25mm bolts, a gallon of anti-freeze, simple hand tools, a few blocks of wood, a rolling floor jack, and jack stands. It is a good time to replace the belts, so get both of them. Yes, you do have to move the engine.A little.
1. Jack up the car on one side, place a smaller jackstand under the car where the front stabalizer is bolted to the frame. You just need to get the car up enough to remove the front plastic splashpan. Now remove the splashpan, grip it firmly, and toss it at the nearest BMW engineer to show your gratitude for designing a car that has a sheet metal support with webing placed directly infront of the water pump, thereby making it necessary to move the engine in order to remove the water pump, even though there is enough room infront of the sheet metal support to be able to desing it with a slight 1" dip towards the front of the car thereby providing enough clearance to simply remove the water pump unimpeded. Now, jack up the car a little higher, and remove your small jackstand and place a big jackstand (now that you have the clearance) under the car. Place the jack on the other side, and jack it up enough to place another large jackstand under the car at the point where the anti-sway bar (stabilizer) bolts to the frame. Now place a rolling floorjack under the engine and place a block of wood between the jack and the oilpan at the front of the engine. Make sure this block of wood is long enough to support the load across the entire width of the oilpan, in order to srpead the weight of the engine across as much of the oilpan as possible, for obvious reasons. You just need to jack it up to meet the oilpan, don't go any higher yet. The reason you do this now is because the underside of the engine will soon become wet with anti-freeze, making everything slippery.
2. Now remove the belt for the A/C compressor (torx bit needed for tensioner)
3. Remove the top plastic (fanshroud?) Cover and loosen but don't remove the bolts on the water pump pulley. Remove the serpentine belt. 16mm socket for the tensioner.
4. Now remove the 10mm bolts on the water pump pulley. Tap the pulley gently to get it off. It is made of plastic, so be careful. Remove the 10mm nuts on the water pump. Now install your m6x25mm bolts into the threaded holes on the water pump. Tighten them, and this will remove the water pump from the engine block. The coolant will spill out, but it won't be a lot. Now remove the upper radiator hose only where it connects to the engine by prying the metal clip. Push it up out of the way against the oil filter housing. You can remove the hose before removing the pump, but I did not because it would otherwise make everything wet that I still have to work on.
5. Now remove the nut at the left engine mount. I think it is a 16mm, might have been 15mm.
6. Jack up the engine slowly, but only go up to the point where the engine mounting bolt is just at the lip of the engine mount, where it almost clears the engine mount, but no further. (I would not want to have to line that thing up upon installation. Besides, it is not necessary to go that far.) You should now be able to pull out the water pump going in the direction of the passenger side.
Ta Da! You've now saved your self a lot of money. Now install the new water pump by lubricating the new o-ring with a little ant-freeze on your hand, and install the water pump. Put the car back together. Pour in some anti-freeze. With the car and the heater running, bleed the air out of the cooling system. (With the bleeder screw located next to the resevior cap.) But keep the old water pump. You will need this during your next trip to Germany, when you get the opportunity to throw it at the head of a BMW z4 engineer. This will make them think! It would be different if these water pumps did not fail prematurely.
Hope this helps!
May, 26, 2008 AT 7:06 PM
I totally agree with the trip to Germany and the water pump to the head of the engineer! You now have an idea of what types of engineering f*** ups that we as BMW technicians have to deal with. One of the reasons I don't work at the dealership anymore is having to be held accountable for poor engineering practices and/or poor quality assurance/control.
April, 10, 2010 AT 12:32 PM
Just wanted to say thanks, you have answered my question on how to remove the water pump in my Z4 without taking the front support/bumper/clip out!