Bad Water Pump???

[dblcrona]

Recently I have been hearing a vibration under the hood when I accelerate in my 2003 Z4 3.0i. The sound levels out at higher RPM’s. Yesterday when I pulled out of the driveway the coolant light came on for just a few seconds which seems to confirm my suspicion that the sound is my water pump going bad. I’m no expert mechanic but I’m very mechanically inclined. I’d like to tackle this project myself if there is a good DIY on this or another forum. Any instructions or insight into this issue would be greatly appreciated. Also, if you think my diagnosis is wrong please say so. Thanks everyone.

Ken

[Smartbear]

Recently I have been hearing a vibration under the hood when I accelerate in my 2003 Z4 3.0i. The sound levels out at higher RPM’s. Yesterday when I pulled out of the driveway the coolant light came on for just a few seconds which seems to confirm my suspicion that the sound is my water pump going bad. I’m no expert mechanic but I’m very mechanically inclined. I’d like to tackle this project myself if there is a good DIY on this or another forum. Any instructions or insight into this issue would be greatly appreciated. Also, if you think my diagnosis is wrong please say so. Thanks everyone.

Ken

Hi, usually a failing pump leads to overheating or a radiator fan pulsing on/off from a cold start. Get the codes read & look for “implausible pump speed” or similar
Use the search function on here and it should bring up some info on changing the pump, don’t purchase the pierburg pump from bmw as they will charge double!
Rob

[Smartbear]

Ignore my comments above, I thought you had a facelift car with the electronic pump but you have a mechanical pump fitted to an 03 car
Rob

[ph001]

There is no connection between your coolant light and the water pump, the former being a coolant level indicator rather than flow. A bad pump usually manufests as overheating on the temp gauge and cold heaters.

[patriot66]

Hi OP. Coincidentally my water pump started to fail on me early last week. I was sitting in traffic and saw a few wisps of steam rising from the end of my bonnet. I kept my eye on the temp gauge which didn't budge over normal and when I got home opened the bonnet to find the seals/bearing on the pump had failed leaking about a pint of coolant on to the belts spraying it all over the place ! This is the original '03 pump with 78k miles on it.
I ordered on Ebay a Meyle HD water pump, Wahler Thermostat and a couple of new Gates belts whilst I was doing. Started fitting them this evening but ran out of daylight. It is quite straightforward a job, the only fly in the ointment being you need to remove the engine mount bolt on the nearside and jack the engine up on the nearside sump with a block of wood so that you can wangle the old pump out and the new one in or it will foul on the front cross member behind the radiator. This video I found on YouTube explains all :https://youtu.be/YKphkCyEccs
Hoping to get the job finished tomorrow/Tuesday so if possible I'll post a few photos that may be helpful

[dblcrona]

There is no connection between your coolant light and the water pump, the former being a coolant level indicator rather than flow. A bad pump usually manufests as overheating on the temp gauge and cold heaters.

When a water pump fails it can leak so definitely there can be a connection between low fluid level and a failing water pump.

[dblcrona]

Is this a job that can be done from topside? I don’t have access to a lift.

Hi OP. Coincidentally my water pump started to fail on me early last week. I was sitting in traffic and saw a few wisps of steam rising from the end of my bonnet. I kept my eye on the temp gauge which didn't budge over normal and when I got home opened the bonnet to find the seals/bearing on the pump had failed leaking about a pint of coolant on to the belts spraying it all over the place ! This is the original '03 pump with 78k miles on it.
I ordered on Ebay a Meyle HD water pump, Wahler Thermostat and a couple of new Gates belts whilst I was doing. Started fitting them this evening but ran out of daylight. It is quite straightforward a job, the only fly in the ointment being you need to remove the engine mount bolt on the nearside and jack the engine up on the nearside sump with a block of wood so that you can wangle the old pump out and the new one in or it will foul on the front cross member behind the radiator. This video I found on YouTube explains all :https://youtu.be/YKphkCyEccs
Hoping to get the job finished tomorrow/Tuesday so if possible I'll post a few photos that may be helpful

[patriot66]

No. You need to get access underneath to undo the left side engine mount bolt and jack the engine up. Also you need to remove the under-shield from the engine bay so that you can drain the coolant. I have mine up on wheel ramps.

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Change of plans as I have been working today so I will try to complete this job tomorrow(Tuesday) and post a few possibly useful photos.

[dblcrona]

Ok, I may give it a try. Can I ask what your total cost was to do this job?

No. You need to get access underneath to undo the left side engine mount bolt and jack the engine up. Also you need to remove the under-shield from the engine bay so that you can drain the coolant. I have mine up on wheel ramps. 20181112_153408.jpg
Change of plans as I have been working today so I will try to complete this job tomorrow(Tuesday) and post a few possibly useful photos.

[patriot66]

I bought all my parts on EBay for about £80/$100. I already had some coolant in my garage.

[kis]

Alternative method for M54 pump here (found on my travels)

[ph001]

Have you actually confirmed you have coolant leaking from the pump? Usually pretty obvious through lots of steam or coolant all over your drive / garage.

[patriot66]

Completed my water pump and thermostat replacement today. All very straight forward and went very smoothly.
This is the 16mm engine mount bolt centre of photo and is easily accessible from below working through the left side lower wishbone with a ratchet and 'wobble drive' extension

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This is the old pump in situ.

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You can see in this photo it looks like it has been weeping from the small vent hole for some time. Also the o-ring seal doesn't look 100% either. There was a small amount of play in the bearings too

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The nasty plastic impeller was fine but the new Meyle HD unit has a superior metal one.

Thermostat housing

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Water pump housing

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New water pump in situ

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I fitted 2 new belts, reconnected the hoses and electrical connectors, refilled with fresh coolant (Comma Xstream G48) ran it up to temperature and bled it from the bleed screw. Just need to check the level again in the morning