4.4 water pump nightmare

[faranks]

hello, new to this forum, bought a 2000 x5 4.4 with 80k on it about 4 months ago... water pump grenaded yesterday. looked like it was easily accessible and didn't want to pay for something typically simple, so tackled it myself. Everyone talks about removing the 32mm nut on the fan clutch being so easy (yes it's reverse threaded), maybe with the special bmw tool, but I cannot even remove the fan shroud without removing fan first, and don't see how it's possible. Anyways, does anyone know why the M62 engine needs 2 fans? it has a large electric fan that looks plenty up to the job, yet it has the other fan running through an archaic viscous clutch, that correct me if I'm wrong- just runs slower and slower as the fluid inside thins with heat. Has anyone removed that fan and just ran with the electric? Also nice $85 thermostat that sans the housing, looks just like the $6 one in my Ford truck. Love the way it drives though!! thanks

[Laurence]

Originally Posted by faranks

hello, new to this forum, bought a 2000 x5 4.4 with 80k on it about 4 months ago... water pump grenaded yesterday. looked like it was easily accessible and didn't want to pay for something typically simple, so tackled it myself. Everyone talks about removing the 32mm nut on the fan clutch being so easy (yes it's reverse threaded), maybe with the special bmw tool, but I cannot even remove the fan shroud without removing fan first, and don't see how it's possible. Anyways, does anyone know why the M62 engine needs 2 fans? it has a large electric fan that looks plenty up to the job, yet it has the other fan running through an archaic viscous clutch, that correct me if I'm wrong- just runs slower and slower as the fluid inside thins with heat. Has anyone removed that fan and just ran with the electric? Also nice $85 thermostat that sans the housing, looks just like the $6 one in my Ford truck. Love the way it drives though!! thanks

I can't help you on the fan removal, but may be able to answer the question on needing two fans, this is almost certainly due to the air conditioning.
There are two "radiators", one for engine cooling and another for the air conditioning condensor (shown below).



Now, I'm not sure if the two fans are interconnected, but its likely that the electric fan only operates based on the cooling requirements of the aircon system only.

Whist the Viscous coupling may seem archaic, it does the job well. If you remove it, you'll have to replace it with something or else risk damaging the engine.
There is a good article here on viscous coupling operation http://www.aaroncake.net/rx-7/efanmyth.htm

[fast4d]

most recent bimmers have electric pusher fans to augment the mech fan. the electric fans come on with A/C and help when you're sitting in heavy traffic. some people delete the mech fan and change the sensor that triggers the elec fans at a lower temp.

[flekz]

the fan shroud is being held in by some push in type clips.. if im not mistakened... theres 2 on the middle of the fan shroud mid way down the rad.. and then 2 at the top... u have to angle the shroud a lil odd to get it out... after u get the fan out if i remember how i do it i had the 32 mm bar slightly to the left of the middle if lookin at the motor from the front of the car and a breaker bar between the fan clutch and the bolt holding the fan clutch in place. i had the breaker bar slightly to the right of the middle of the m otor and then flexed both of em going towards each other... i actually couldn't even break em loose with my hands... i stood on both sides with my feet and started jumping on them to get em loose to be honest with u and i heard a snap, i thought i broke something but it loosened... if u wanna ask me more about it my screen name is flekz... im online at night most of the time

[faranks]

thanks for the feedback. Turns out that I had a "special" fan clutch 32mm bolt. I didn't want to wait to order the BMW special tool, and the whole screwdriver trick everyone talks about was useless. I ended up fabricating my own, bent it, made a thicker one. It took my 230lb buddy getting in the engine compartment, foot on the tool, and about 100+ ft/lbs of torque to finally break it loose, also breaking the plastic pulley in half. Upon inspection it seems the bearings gave out, the impellers intact. Interestingly enough the impellers are metal, and beautifully brazened whereas the Graf replacement has metal impellers also, but boast 2 small tack welds each. All that I have read states that the oem impellers should be plastic, so does that mean the waterpump had already been replaced, possibly explaining the massive amount of torque needed to get off that 32mm bolt (it did have a suspicious marring on one of the leading edges)?