M54 coolant leak help please

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enuff_zed
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M54 coolant leak help please

Post by enuff_zed » Sat Oct 17, 2020 2:37 pm

Hi all,
Wife rang from 5 miles away to say her E85 2.5i had lit up the low coolant warning light.
I went to find her, topped it up and got it home no big problems.

Now up on ramps, got the undertray off and the whole front end of the engine is covered in water splashes.
Dried it all off and fired it up. After about 5 minutes, once heat and pressure had built up I noticed a small amount of spray but not able to determine where from as the belts were throwing it everywhere.
Turned the engine off and instantly got a lot of water running straight down the front, pouring off the bottom pulley.
I can see all the hose connections etc and nothing coming from them.

Do we think this is likely to be water pump, or something else up there?

Just looking for pointers really, as with limited access on my gravel drive it is very likely to be heading to the local indy.

Had plenty of water pumps go on older Fords etc, and they've dripped out from the tell-tale hole in front of the bearing. But this is pouring out and I know for a fact there was no issue 2 days ago as I checked the levels and cleaned the engine bay. It seems to have let go suddenly, whatever it is.

Any suggestions to help narrow it down would be gratefully accepted.
Last edited by enuff_zed on Sun Oct 18, 2020 9:23 am, edited 1 time in total.
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M54 coolant leak help lease

Post by Chris_D » Sat Oct 17, 2020 2:47 pm

Your expansion tank has ruptured most likely.
Usually difficult to see as it manifests as a hairline crack/s, especially difficult to see if it's near the bottom.
Have the coolant hoses been replaced from new? If not, it could also very well be one of these that's gone brittle and ruptured.
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M54 coolant leak help lease

Post by enuff_zed » Sat Oct 17, 2020 2:54 pm

Chris_D wrote: Sat Oct 17, 2020 2:47 pm Your expansion tank has ruptured most likely.
Usually difficult to see as it manifests as a hairline crack/s, especially difficult to see if it's near the bottom.
Have the coolant hoses been replaced from new? If not, it could also very well be one of these that's gone brittle and ruptured.
Cheers Chris, I fitted a new tank about 3 months ago. First thing I did was check that, just in case.
But the water is definitely pouring down the front, behind the pulleys.
Very difficult to be sure, but cannot see any split hoses etc.
What leads me away from them is that I would expect a split hose to fire out a high pressure jet of water, then seal itself a bit once the engine turned off.
This is more akin to a tap running than water squeezing out of a small hole.
Tbh, the car has just clocked over 100k, so new pump, thermostat, belts etc wouldn't be a bad idea anyway.
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M54 coolant leak help lease

Post by Chris_D » Sat Oct 17, 2020 3:13 pm

enuff_zed wrote: Sat Oct 17, 2020 2:54 pm
Chris_D wrote: Sat Oct 17, 2020 2:47 pm Your expansion tank has ruptured most likely.
Usually difficult to see as it manifests as a hairline crack/s, especially difficult to see if it's near the bottom.
Have the coolant hoses been replaced from new? If not, it could also very well be one of these that's gone brittle and ruptured.
Cheers Chris, I fitted a new tank about 3 months ago. First thing I did was check that, just in case.
But the water is definitely pouring down the front, behind the pulleys.
Very difficult to be sure, but cannot see any split hoses etc.
What leads me away from them is that I would expect a split hose to fire out a high pressure jet of water, then seal itself a bit once the engine turned off.
This is more akin to a tap running than water squeezing out of a small hole.
Tbh, the car has just clocked over 100k, so new pump, thermostat, belts etc wouldn't be a bad idea anyway.
Hole in the rad itself?
take the grills off and have a good look with a torch.
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M54 coolant leak help lease

Post by enuff_zed » Sat Oct 17, 2020 3:16 pm

Ok, wormed my way underneath for a better look. With the cap off, bit like taking your finger off the end of a straw, the water runs out freely.
Followed it back up round the bottom pulley to the underside of the water pump. With a 'kin great torch to light it better, I can see water running from the bottom of the pump housing, so fairly convinced it's that.

So wifey then says, well why don't you do it, how hard can it be?

So................. about to order a new pump and thermostat.

Anything else I should be doing while I'm in there?
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M54 coolant leak help lease

Post by patriot66 » Sat Oct 17, 2020 11:50 pm

My waterpump failed suddenly a couple of years ago. This link is to a thread from just a couple of weeks after but may answer your questions
viewtopic.php?f=3&t=110425&p=1595262&hi ... t#p1595262 :thumbsup:
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M54 coolant leak help please

Post by enuff_zed » Sun Oct 18, 2020 9:30 am

patriot66 wrote: Sat Oct 17, 2020 11:50 pm My waterpump failed suddenly a couple of years ago. This link is to a thread from just a couple of weeks after but may answer your questions
viewtopic.php?f=3&t=110425&p=1595262&hi ... t#p1595262 :thumbsup:
It does indeed. Thanks for the pointer.

A big thank you also to Bigwinn, who has recently changed his pump and took the time last night to type out the complete process for me to follow, including recommendations to check out the temp sensor and the belts while I'm in there.

Whenever I have a Z4 issue I am fairly relaxed knowing that this forum will soon give me all the answers.
Just waiting on the parts to arrive now, then I'll let you know how it goes.
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M54 coolant leak help please

Post by patriot66 » Sun Oct 18, 2020 5:52 pm

enuff_zed wrote: Sun Oct 18, 2020 9:30 am
patriot66 wrote: Sat Oct 17, 2020 11:50 pm My waterpump failed suddenly a couple of years ago. This link is to a thread from just a couple of weeks after but may answer your questions
viewtopic.php?f=3&t=110425&p=1595262&hi ... t#p1595262 :thumbsup:
It does indeed. Thanks for the pointer.

A big thank you also to Bigwinn, who has recently changed his pump and took the time last night to type out the complete process for me to follow, including recommendations to check out the temp sensor and the belts while I'm in there.

Whenever I have a Z4 issue I am fairly relaxed knowing that this forum will soon give me all the answers.
Just waiting on the parts to arrive now, then I'll let you know how it goes.
:) :thumbsup:
'03 Sterling Grey 2.5i SE / SMG / Matching Hardtop / Gloss Black MV3s / Bilstein B4s / DLV Backbox / Rebuilt VANOS / Carbon-wrapped Interior Trim / Re-Covered Steering Wheel / De-tango'd !

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M54 coolant leak help please

Post by enuff_zed » Sun Oct 18, 2020 5:53 pm

Well the antifreeze has arrived.....................that's a start :rofl:
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M54 coolant leak help please

Post by bigwinn » Sun Oct 18, 2020 6:05 pm

patriot66 wrote: Sun Oct 18, 2020 5:52 pm
enuff_zed wrote: Sun Oct 18, 2020 9:30 am
patriot66 wrote: Sat Oct 17, 2020 11:50 pm My waterpump failed suddenly a couple of years ago. This link is to a thread from just a couple of weeks after but may answer your questions
viewtopic.php?f=3&t=110425&p=1595262&hi ... t#p1595262 :thumbsup:
It does indeed. Thanks for the pointer.

A big thank you also to Bigwinn, who has recently changed his pump and took the time last night to type out the complete process for me to follow, including recommendations to check out the temp sensor and the belts while I'm in there.

Whenever I have a Z4 issue I am fairly relaxed knowing that this forum will soon give me all the answers.
Just waiting on the parts to arrive now, then I'll let you know how it goes.
:) :thumbsup:
Original credit to Simon Patriot66- who helped me in the first place!

Gotta love the forum- and I have to say compared to other BMW forums, less to55ers

:rofl:
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M54 coolant leak help please

Post by patriot66 » Sun Oct 18, 2020 6:10 pm

bigwinn wrote: Sun Oct 18, 2020 6:05 pm
patriot66 wrote: Sun Oct 18, 2020 5:52 pm
enuff_zed wrote: Sun Oct 18, 2020 9:30 am

It does indeed. Thanks for the pointer.

A big thank you also to Bigwinn, who has recently changed his pump and took the time last night to type out the complete process for me to follow, including recommendations to check out the temp sensor and the belts while I'm in there.

Whenever I have a Z4 issue I am fairly relaxed knowing that this forum will soon give me all the answers.
Just waiting on the parts to arrive now, then I'll let you know how it goes.
:) :thumbsup:
Original credit to Simon Patriot66- who helped me in the first place!

Gotta love the forum- and I have to say compared to other BMW forums, less to55ers

:rofl:
I've picked up plenty of tips and hints myself on this forum in the 5.5 years I've been a member. It's a pleasure to pass on any acquired or learned information to members that are looking for help/hints :)
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M54 coolant leak help please

Post by enuff_zed » Sun Oct 18, 2020 6:10 pm

bigwinn wrote: Sun Oct 18, 2020 6:05 pm
patriot66 wrote: Sun Oct 18, 2020 5:52 pm
enuff_zed wrote: Sun Oct 18, 2020 9:30 am

It does indeed. Thanks for the pointer.

A big thank you also to Bigwinn, who has recently changed his pump and took the time last night to type out the complete process for me to follow, including recommendations to check out the temp sensor and the belts while I'm in there.

Whenever I have a Z4 issue I am fairly relaxed knowing that this forum will soon give me all the answers.
Just waiting on the parts to arrive now, then I'll let you know how it goes.
:) :thumbsup:
Original credit to Simon Patriot66- who helped me in the first place!

Gotta love the forum- and I have to say compared to other BMW forums, less to55ers

:rofl:
And it continues in that vein. Once I've done these jobs I'll be passing on what I can too.
In fact, as long as I'm sure I know what I'm doing, I'd happily be offering to help out if needed.
E89 20i SDrive M Sport - Valencia Orange
E85 2.5i - Sterling Grey - Better half's fun car

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