Antifreeze Capacity? where's it hiding?

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sirius-c
Joined: Wed 12 Dec, 2012 22:24
Posts: 499

  Z3 roadster 2.8
Location: Eeh ba gum lad, 'ow do?

Antifreeze Capacity? where's it hiding?

Post by sirius-c »

I recently performed a coolant change.
All references state that a 1997 2.8 (M52B28) holds 10 1/2 Litres.

I removed the radiator plug which drained a little over 3 litres, then I removed the engine drain bolt which drained approx 2 litres, i also had the thermostat housing off and replaced the gaskets (it was leaking) and the rad hoses....all in all a little over 5 litres was drained.
I ran the engine briefly with both plugs removed in an effort to remove the remaining 5 litres of existing coolant, I squeezed hoses, and I even gave the expansion tank a blow job!

is this normal? where on earth could the other 5 litres be hiding?
Im baffled

A member of my family is a mechanic (40 years plus of experience) and was present when I did all this work, he's adamant it cannot possibly hold 10 1/2 litres and does not believe 5 litres is hiding somewhere.
Designed or not designed, that is the question.
Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2136

  Z3 roadster 1.9

Re: Antifreeze Capacity? where's it hiding?

Post by Del »

I agree the original BMW owners manual states 10.5 litres (including the heater circuit) which does seem a big increase, proportionately on the 1.9 (6.5 litres) given that the engine oil capacity is 5 litres (1.9) and 6.5 litres (2.8). :shrug
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leahandsteve
Joined: Sat 29 Sep, 2007 20:02
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  Z3 roadster 1.9
Location: Stokenchurch (J5 M40)

Re: Antifreeze Capacity? where's it hiding?

Post by leahandsteve »

TYpe in last 7 digits of your vin into this:

http://www.bmw-z1.com/VIN/VINdecode-e.cgi

will tell you all you need to know.
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sirius-c
Joined: Wed 12 Dec, 2012 22:24
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  Z3 roadster 2.8
Location: Eeh ba gum lad, 'ow do?

Re: Antifreeze Capacity? where's it hiding?

Post by sirius-c »

leahandsteve wrote:TYpe in last 7 digits of your vin into this:

http://www.bmw-z1.com/VIN/VINdecode-e.cgi

will tell you all you need to know.

thanks for reply....
that confirms its 10 litres so I'm still baffled. :shrug
Designed or not designed, that is the question.
Alan W
Joined: Thu 20 Jun, 2013 10:56
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  Z3 roadster 2.8
Location: Bexley, Kent UK

Re: Antifreeze Capacity? where's it hiding?

Post by Alan W »

Just replaced the water pump, thermostat and radiator on my 2.8 and the shop I bought anti-freeze from told me 10 litres capacity 50/50 mix (5 litres anti freeze plus 5 litres de-ionised water).. however I only managed to get the 5 litres of anti freeze and just 2.5 litres of the water in so I'm guessing that some of the water had remained trapped in the block and/or in the heater matrix..
1999 facelit Z3 Roadster 2.8 Auto in Cosmos Black aka 'Gloria'
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Zedbedee
Joined: Sun 15 Mar, 2009 20:04
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  Z3 roadster 2.0
Location: Yeovil

Re: Antifreeze Capacity? where's it hiding?

Post by Zedbedee »

I can remember a similar situation about 5 years ago when I changed the thermostat and coolant. I'm just about to change the coolant again ( when the rain stops!) but my plan is to disconnect the top and bottom hoses and flush through with the garden hose for a while from the top. Have a missed any potential problems if I do this??
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
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  Z3 roadster 3.0i
Location: Johannesburg

Re: Antifreeze Capacity? where's it hiding?

Post by Southernboy »

There's a quantity of water in the heater matrix, plus there's an amount in the engine block. When you drain the radiator, it largely only drains out coolant from the radiator and the cylinder head... so you have a residual amount still in the system.
In the "old days" there used to be a "tap" fitted to the side of the engine block from which one could drain the block too.
Using a garden hose to flush out the system is OK, but bear in mind you will be leaving a couple of liters of tap water in the system. If you want to get it out, you will need to pump distilled water through in sufficient quantity to flush the system and then drain the system as per the bottom of the radiator, measure the amount in liters collected, and calculate the amount of coolant you will need to mix into that drained amount to compensate for the "clean" water still in the engine / heater matrix etc so you achieve the correct mixture specified.
ie. If your system specification is 10 liters, and you have 8 litres of clean water drained into the container, there will be 2 liters still in the engine - so, the mixture you will need to make with the 8 liters will need to be greater than 50 / 50.
"Normal is overrated"
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sirius-c
Joined: Wed 12 Dec, 2012 22:24
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  Z3 roadster 2.8
Location: Eeh ba gum lad, 'ow do?

Re: Antifreeze Capacity? where's it hiding?

Post by sirius-c »

Zedbedee wrote:I can remember a similar situation about 5 years ago when I changed the thermostat and coolant. I'm just about to change the coolant again ( when the rain stops!) but my plan is to disconnect the top and bottom hoses and flush through with the garden hose for a while from the top. Have a missed any potential problems if I do this??
Ive always been told to "back flush" a rad...
as water returns from the block via the top hose to the rad and is fed back cooler to the block via the bottom hose......
so in this particular case i would remove the rad, turn it upside down and put the garden hose in the bottom hose which now becomes the top because its upside down. :puzzle:

Southernboy wrote:and calculate the amount of coolant you will need to mix into that drained amount to compensate for the "clean" water still in the engine / heater matrix etc so you achieve the correct mixture specified.
Good point, I did three flushes with de-ionized/distilled water prior to adding antifreeze in an effort to dilute the existing contents right down to distilled water only
(I'm not putting tap water into it, the water here has the ability to grows skeletons in my kettle :shock: ), each time driving around a while between flushes/fills, then I measured what was drained and mixed accordingly.
A coolant tester from HalFrauds helped with this

I still think 5 litres is a lot to be hiding somewhere, it must be one huge heater matrix!
Designed or not designed, that is the question.
Zedbedee
Joined: Sun 15 Mar, 2009 20:04
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  Z3 roadster 2.0
Location: Yeovil

Re: Antifreeze Capacity? where's it hiding?

Post by Zedbedee »

I will probably remove the rad and back flush as it's relatively easy to do. I have 5 litres of long life antifreeze so as long as I can flush as much of the old coolant out as possible and can get the 5 litres in and topped up with water it will have a 50/50 solution. I really don't see the point of using anything other than tap water, which I have used for years with no problems. OK so your kettle may get a layer of limescale inside but that is the accumulation of dozens of kettles being boiled. We clean our kettle with white vinegar regularly and it takes many fillings to show any sign of limescale after cleaning.
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sirius-c
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  Z3 roadster 2.8
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Re: Antifreeze Capacity? where's it hiding?

Post by sirius-c »

Zedbedee wrote:I have 5 litres of long life antifreeze
I've always stuck with the blue stuff as specified for fear of the green or red antifreeze munching through seals etc, is this non-sense? :rtm:
I'd like to put the red type in as it lasts longer.
Designed or not designed, that is the question.
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