Coolant flushing

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dazthephot
Joined: Wed 09 Apr, 2008 18:58
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Coolant flushing

Post by dazthephot »

Ok so it's time for a coolant flush and replace.
I want to use distilled water as the good book says but is that really necessary?

I guess if it is I'll have to flush with it too as I've been topping up with tap water over the years.




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BladeRunner919
Joined: Fri 17 Feb, 2012 20:18
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  Z3 roadster 1.9

Re: Coolant flushing

Post by BladeRunner919 »

Not necessary, but it's so cheap, why wouldn't you? :D
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

very true..
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

BladeRunner919 wrote:Not necessary, but it's so cheap, why wouldn't you? :D
I don't suppose you know the capacity do you?


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BladeRunner919
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  Z3 roadster 1.9

Re: Coolant flushing

Post by BladeRunner919 »

My M44 is about 5 liters all in - not sure what engine you have.
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

Sorry. 1.9 m43


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mrscalex
Joined: Fri 13 Mar, 2015 09:14
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  Z3 roadster 1.9

Re: Coolant flushing

Post by mrscalex »

When you drain the system via the radiator and block plug I believe a quantity of coolant remains in the heater matrix.

So if you flush with plain water you will leave a quantity of it in the system. And whether you flush with plain or distilled you'll need to remember to make a stronger mix of coolant to water to compensate.

I just flush out the radiator as that can drain fully. I'd rather have a bit of old coolant that gets mixed in than use plain water that could cause some distress to the internals. Particularly as we live in a very hard water area.
ImageImage
2001 Z3 2.2 Topaz Blue (Trudy) - Keeper rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Cookies) - Keeper rebuilt having been bought with a seized engine
2002 Z3 3.0 Sapphire Black (Peanut) - Keeper awaiting rebuilding having been bought as an abandoned project
Plus Willy, Kodak & Maycee - All 2.2 Sport projects. Yes, 6 is a lot of Z3s :)
Always happy to try and help with spares :)
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

Do you use normal anti freeze or the premixed bmw stuff?


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mrscalex
Joined: Fri 13 Mar, 2015 09:14
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  Z3 roadster 1.9

Re: Coolant flushing

Post by mrscalex »

BMW concentrate.

I'd happily use Halfords or quality alternative but the BMW stuff comes in around the same price.
ImageImage
2001 Z3 2.2 Topaz Blue (Trudy) - Keeper rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Cookies) - Keeper rebuilt having been bought with a seized engine
2002 Z3 3.0 Sapphire Black (Peanut) - Keeper awaiting rebuilding having been bought as an abandoned project
Plus Willy, Kodak & Maycee - All 2.2 Sport projects. Yes, 6 is a lot of Z3s :)
Always happy to try and help with spares :)
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

Oh right so it's not pre mixed it needs diluting with distilled water or have I got that wrong and you just pour it straight in?


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Del
Joined: Sat 19 Nov, 2011 18:35
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  Z3 roadster 1.9

Re: Coolant flushing

Post by Del »

The BMW stuff is strange blue, inky looking stuff which I haven't been able to duplicate elsewhere - it's longlife so I tend to stick with it. I get my distilled water from Tesco - just over £1 for 2.5 litres. I 50/50 mix it in a separate container (litre by litre) and pour it in.
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

Ah beauty thanks seems an easy way to go.


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Cooper01
Joined: Tue 29 Apr, 2014 08:06
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  Z3 roadster 3.0i

Re: Coolant flushing

Post by Cooper01 »

I have been reading up a lot about this as I suspect my heater matrix is a bit clogged.

From my research I conclude:....

When you do the flush ensure that the heater is on the max setting to keep the matrix open fully.
drain the radiator and coolant from the block, if you have a screw in there for draining.
if the system if contaminated use a flush as per product procedure.
only use the bmw blue coolant. the dilution instructions are on the bottle.
use distilled water only. tap water contains contaminants which can foul the system and heater matrix [it gets HOT in there]
bleed the system, run the engine, check levels and top up as required.

Note:
The plastic plug in the radiator is likely to be very brittle so be prepared to get a replacement [they are expensive!] :head:
bmw recommends replacing the coolant every 4 years in the Z3 and 3 years in the ///M.

cheers.
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

Thank you for the advice. I bought 12 litres of deionised water from Tesco cos it was only a pound or so for 2.5l. I got 3l of bmw coolant for about £20 from a bmw geezer on fleabay. So I'm ready to go.
I'm guessing that you turn the heater dial to hot then put the ignition on and run the fan? Right ?


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dazthephot
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Re: Coolant flushing

Post by dazthephot »

Also once you've filled it with deionised water for the initial flush would you run the engine a short while to circulate it?


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Cooper01
Joined: Tue 29 Apr, 2014 08:06
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  Z3 roadster 3.0i

Re: Coolant flushing

Post by Cooper01 »

Hi. Watch YouTube videos particularly Otto from Bavarian Auto.

I am going to flush with an​ engine flush product in my coolant. Run with heater on highest setting no need for the fan to be on, then Drain. Then fill with tap water and run. Drain. Then run with distilled water, not any other type, and drain. Some water will remain but that's ok because it is distilled. Then calculate the amount of BMW coolant required and put all of that in. Fill with the water. Run, bleed, and top up with the water. Done. Always leave the heater on highest setting.

It might be excessive but I want the system to be really clean and functioning to is highest level.
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dazthephot
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Re: Coolant flushing

Post by dazthephot »

Thanks for the tip.


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