BMW Z3 Thermostat and water pump (massive of course!)

[Zeti]

Hi all,
Five years ago when I bought my Zed from 1996, after a very close inspection, I found that all parts on the car were from factory. I started the search on different forums in order to find out what is falling and when, so I can avoid unnecessary costs when travelling abroad (especially that ruin the holiday could create more damages from my wife's side, as we all know!)
I found out (including from the BMW dealer) that water pump life time it's about 90-100 000km and the thermostat plastic hooks usually get broken, for ageing and the water hardly reach the right temp when chili outside....Last autumn I noticed some times the engine's temp droping so I imagined the Thermostat it's faulty: broken plastic bracket. As the water pump breakage brings colateral damages (fan, cooling radiator, hoses, and so on ) I decided to change them both, but I was scared by the obstinacy that some mates described, when trying to extract the water pump from the engine: hammer, WD40, swearing, etc). Because my Zed has 171 000 km I decided to not take any risk and start the procedure!
Everything went nice (no swearing) and smooth like in a Pelican or TIS description and the surprise was that despite of all estimations the water pump was in a great condition (I still have tears in my eyes ! like loosing a good friend) and the famous plastic brackets of the thermostat were in position!

The engine it's looking great, no corrosion......

When opening the packing box of the Bugatti water pump , purchased from Ebay, surprise:

With more tears into my eyes, this time swearing included too, I ordered a Ruville water pump:

So the myths regarding water pump life time max 100 000 km (mine 171 000 km and still great shape!) and breakage of the plastic brackets of the thermostat aren't always true! Myth Busted! Maybe the engine was never overheated and always with quality antifreeze or it's just the God of mechanics smiling sometimes......
But the thermostat was faulty; I have seen how the new one works after running the engine.
Conclusion: I love the M44!

 

[zedonist]

I love the M44!

+1, Cracking 16v Engine, i wonder how many mechanics would have fitted that pump without noticing the defect in the casting, good call

 

[GazHyde]

That was a great spot on your eBay water pump, well done! It's a great thing to bring to everyone's attention too, that we should all inspect parts - not only the old ones when they come off but the new ones about to go on!

The bearings had failed on mine, but like yours the plastic impellers looked brand new! A lot can be learnt from just taking your time and opening your eyes!

 

[Zeti]

That was a great spot on your eBay water pump, well done! It's a great thing to bring to everyone's attention too, that we should all inspect parts - not only the old ones when they come off but the new ones about to go on!

The bearings had failed on mine, but like yours the plastic impellers looked brand new! A lot can be learnt from just taking your time and opening your eyes!

The impeller of the Bugatti cracked pump it's turning quiet smooth and the packaging it's without sign of damage (dropping) during the transport. So sadly I have to admit that it was dropped before packaging......
Maybe it's not the fault of the great name, but it's in their yard.....
Conclusion: don't mix the German parts with Italian aftermarket , although Italian manufacturer are also sometimes OEM for BMW.....

 

[zedonist]

Don't beat yourself up, it is a casting defect, either a short or shrinkage, they should have spotted it though.........

 

[jonco]

It happens. I bought a new expansion tank and all looked good but it leaked when fitted Unlike you I missed the flaw

 

[Zeti]

It happens. I bought a new expansion tank and all looked good but it leaked when fitted Unlike you I missed the flaw

Yes, sad.
My naive question is : they do that deliberately (knowing the hidden defect) or just by not giving the right attention?

 

[zedonist]

The Automotive industry is all about process control and zero defect sampling, i would guess that they had a process issue that was not detected, and the sampling size was not large enough to spot the defect, which gives you confidence there would not be many rejects. That said, pretty annoying or disastrous if you buy the one or two and fit them. Product recalls (in basic terms) are worked on the same basis of probability, they rated from injury to occupants down to annoying niggle. The former will get a recall if it is considered fatal, or a service refit if it is minor injury, the later will only get fixed if a certain amount of customers complain, which is why the boot weld problem never got a mention in the UK, took a class act in the USA.