So I have obviously been very bad. Thinking the trials and tribulations, reported a couple of weeks ago, when changing VANOS seals had left me with a beautifully running Z4, I was very mistaken and disaster number two was imminent!
After a great drive from West Sussex to Newark, Notts to man a stand at the showground for the weekend, Sunday at 4.30 pm, and an unexpected early getaway, saw me joining the M1 at junction 21a. 200 yards onto the motorway and I heard a clunk from the engine bay, the red charging light came on and, within another couple of hundred yards the temperature gauge swept up into the red. I was lucky in one respect as the services slip road was just a few hundred yards away. Knowing the M54 does not react well to overheating (does any engine?) I got in and parked at the first bay I could. Lifting the bonnet and expecting a broken fan belt I wasn’t expecting the serpentine spaghetti that I later unwound from all of the pulleys (photo 1- the A/C belt remains intact and ALL of the rest is shredded serpentine belt!)
A phone call to the AA where I was told it would be a trailer home, as they had no BMW belts, a 3 hour wait for the transporter and the car was back home by 10.30pm, a long day.
Next day I found that the cause of the shredded belt was a water pump which decided to detonate its bearing (photo 2 shows how far the shaft could be moved from side to side).
Having checked all the Z4-Forum postings on water pump replacement I was aware that the same bulkhead that gets in the way of VANOS removal also prevents the pump from sliding the remaining few millimetres out. The recommendation is to undo one of the main engine mount nuts (right side as you face the engine from in front of the car is easiest to get to) and jack the engine up. This involves a great deal of jacking the car up from the ground, getting it up onto axle stands and then using a trolley jack to lift the engine. Not a huge hassle but, as it was pouring with rain, I was doing the job in my single garage with little space either side. After a bit of a think and a look here and there I found that a small scissors jack, which I fortunately had, could be closed right down and would just slip under the mount casting from the engine and sit on a solid crossmember just underneath it. (photo 3).
After undoing the engine mounting nut the jack eye could be turned with a short length of bar and the engine lifted until just off the stud, at which point the water pump, which I had already undone but was fouling on the bulkhead, could be finally slipped out.
With a quoted £125 for a new pump from BMW, I opted for a German made Meyle at £35 delivered next day.
A couple of points.
The undertray can be removed without jacking up the car if you get to the back bolts from the front corners of the car, so this whole water pump replacement can be done with the car on the ground, not a huge saving I know, but saves a bit of faffing about.
Once the new pump is on, adding the pulley to it may require a little more raising of the engine (5mm) to clear that bloody frustrating bulkhead, mine did.
After a great drive from West Sussex to Newark, Notts to man a stand at the showground for the weekend, Sunday at 4.30 pm, and an unexpected early getaway, saw me joining the M1 at junction 21a. 200 yards onto the motorway and I heard a clunk from the engine bay, the red charging light came on and, within another couple of hundred yards the temperature gauge swept up into the red. I was lucky in one respect as the services slip road was just a few hundred yards away. Knowing the M54 does not react well to overheating (does any engine?) I got in and parked at the first bay I could. Lifting the bonnet and expecting a broken fan belt I wasn’t expecting the serpentine spaghetti that I later unwound from all of the pulleys (photo 1- the A/C belt remains intact and ALL of the rest is shredded serpentine belt!)
A phone call to the AA where I was told it would be a trailer home, as they had no BMW belts, a 3 hour wait for the transporter and the car was back home by 10.30pm, a long day.
Next day I found that the cause of the shredded belt was a water pump which decided to detonate its bearing (photo 2 shows how far the shaft could be moved from side to side).
Having checked all the Z4-Forum postings on water pump replacement I was aware that the same bulkhead that gets in the way of VANOS removal also prevents the pump from sliding the remaining few millimetres out. The recommendation is to undo one of the main engine mount nuts (right side as you face the engine from in front of the car is easiest to get to) and jack the engine up. This involves a great deal of jacking the car up from the ground, getting it up onto axle stands and then using a trolley jack to lift the engine. Not a huge hassle but, as it was pouring with rain, I was doing the job in my single garage with little space either side. After a bit of a think and a look here and there I found that a small scissors jack, which I fortunately had, could be closed right down and would just slip under the mount casting from the engine and sit on a solid crossmember just underneath it. (photo 3).
After undoing the engine mounting nut the jack eye could be turned with a short length of bar and the engine lifted until just off the stud, at which point the water pump, which I had already undone but was fouling on the bulkhead, could be finally slipped out.
With a quoted £125 for a new pump from BMW, I opted for a German made Meyle at £35 delivered next day.
A couple of points.
The undertray can be removed without jacking up the car if you get to the back bolts from the front corners of the car, so this whole water pump replacement can be done with the car on the ground, not a huge saving I know, but saves a bit of faffing about.
Once the new pump is on, adding the pulley to it may require a little more raising of the engine (5mm) to clear that bloody frustrating bulkhead, mine did.
