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MINI2 Addick
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61 Posts
Discussion Starter · #1 ·
I topped up my water a little last weekend and havent driven it this week (i get the train to work)

I took the car for a short half hour drive into town on saturday and ended up sitting in a lot of traffic in warmish weather.

When i pulled up i could hear a sort of clicking sound so i went to the engine to investigate.

I found water pouring out from under the lid of the coolant top up tank and it left 3 small patches under the car on the floor (little puddles). The coolant tank was very hot as i suppose it should be - but it shouldnt be building up that much pressure should it?

Took it out again today and the same thing happened. When i checked the level after it had cooled down, it was just under the minimum. Despite all this, the engine temperature stayed at mid level - the same as always - once it had warmed up.

It cant be the thermostat then if the engine is staying at perfect temp - anyone know what this could be?? it has been suggested to me that perhaps there is a pressure release system in the cap that has failed so a new lid might be required??

anyone know??

many thanks

:(
 

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I have seemingly encountered a similar problem with my 52 MCS.

I heard a sort of gargling noise coming from the engine bay so i had a look and all seemed fine until i checked the coolant tank which was empty.

I thought nothing of it and simply refilled the tank then a couple of days later i heard the same noise and guess what? empty tank again.

I decided to have a word with someone at BMW as there is a service centre near me and he told me that it needed to be checked asap as coolant problems could lead to a blown engine. NOT GOOD. I Will get back to you with the diagnosis and hopefully that should be of help.

If anyone else encounters a similar coolant problem plz post with any possible solutions
 

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JCW 210 apparently not!
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516 Posts
does sound like you have an air block in the system somewhere, the car would not show an increase in temperature though the air block could be where you need cooling... get it seen to ASAP
 

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THE STICK
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3,902 Posts
There is a small bleed valve on the front water pipes just between the grill and the intercooler. Its a plastic screw with cross head on it I think. I believe this can be used to bleed the system. Might be worth doing that.

Personally I'd drain and flush the whole system and seewhat occurs.
 
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MINI2 Addick
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61 Posts
Discussion Starter · #8 ·
that dont sound good :(

expensive?

when i have been topping up the water i have NOT done so under pressure - i simply poured the water into the expansion tank when the engine was cool. apparently it is the norm to do this when the car is running normally - could this have caused the problem??
 

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MINI2 Addick
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61 Posts
Discussion Starter · #9 ·
Only I am wondering if i needed to top up whilst the car was running instead of cold - could this have caused the system to depressurise and cause the problem?
 

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MINI2 Addick
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61 Posts
Discussion Starter · #11 ·
But the thing is its only leaking from the top - actually pouring out from under the cap even though its screwed on tight.

cant make it out! does seem to have hapened since i topped up last week though??
 

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Premium Member
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1,068 Posts
it sounds like you have a faulty cap , not regulating at the correct pressure , according to BMW this is a very rare thing ,...... so far I have seen six or more cases -go figure
the caps are not expensive
 

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MINI Obsessed...
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4,989 Posts
Id try a new cap but also when its cold run the engine for a minute or two with the cap off and check to see if the water is bubbling away. If the level stays static then id say defiantly the cap.

If you do replace the cap then it might be worth just bleeding the system a bit too by removing the front bleed valve and making sure it runs freely without bubbles with the engine off. Do top up with the correct type of coolant :)
 

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MINI2 Addick
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61 Posts
Discussion Starter · #14 ·
Thanks guys. I will try that - it only seems to be happening when ive sat in traffic for a while. short sharp journeys seem ok. so that makes me think it might not be that useful to run it for a minute with the cap off. it it really as easy to bleed the system as to simply undo the bleed valve for a minute? I had also just been topping up with water :S
someone else suggested the cap to me as they are more advanced these days than just a plastic cap - am i right in thinking it has a pressure sensor built in to it>?
could be that i spose, and i hope its something that easy!
 

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THE STICK
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3,902 Posts
The cap has a pressure release in it...if that is not opening properly then it'll cause you to leak water and get quite hot (temp guage will sit at normal as it sits at normal at anything between like 85 degrees and 105+ i believe, its not accurate...as a rule as soon as it moves off centre its already way too hot) ...bit like oil warning lights, once its on your engine is already in dire straights and its usually too late :rolleyes:)

I had a new expansion tank as mine had a crack on the jointing of the plastic.... only came to light once the engine got hot.

goOOD Luck, hopefully it'll be simple air in system or faulty cap like Adam and Dave hav said.
 
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