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Coolant ratio 1.8T AUM


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#1 Badgers

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Posted 20 January 2021 - 06:02 PM

Hi Guys, changing the thermostat and coolant on my 1.8T AUM tomorrow. I've got some Comma G30 coolant, this is the correct one as its the same spec as manufacturer's G12. The bottle says for temperatures down to -18 oC use 33% coolant, so 77% water, or for temperatures down to -36 oC use 50% coolant. The guy at the VW dealer said 40% coolant when I called them and I've seen some posts saying 50/50, so what's the general consensus as to what it should be as I haven't got the handbook to check? It definitely doesn't get to -18 oC here! Cheers




#2 adam-

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Posted 20 January 2021 - 07:21 PM

The guy at the dealer is for VW and using VW coolant.  You're not.

 

Use 33%.  Remember you won't get it all out.  I tend to just drain whatever I can and mix it until it's a dark shade.


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#3 NooNoo

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Posted 20 January 2021 - 08:03 PM

I work on colour too  :Y:


Golf 1.8T AGU | 232Bhp | Rtech | k03s | Blueflame turbo-back exhaust | K & N panel | SFS / Forge hoses | TurboRevs SMIC | VR6 Clutch | SMF | Saikou Michi catch can | Bilstein B14s | S3 upper & lower braces | Eibach 25mm ARBs | All SuperPro bushes | 312mm/256mm brakes | 18" BBS RCs | Rline rear | R32 front | Hoefle skirts | OEM Xenons | Retrofit heated seats | One touch demister | W8 Interior light | Sunroof | TT Hubs | TT wishbones | TT quick rack |


#4 Badgers

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Posted 20 January 2021 - 11:49 PM

The guy at the dealer is for VW and using VW coolant.  You're not.

 

Use 33%.  Remember you won't get it all out.  I tend to just drain whatever I can and mix it until it's a dark shade.

 

Great thanks Adam, I'll try and flush it with water first then and then go for 33%, cheers



#5 adam-

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Posted 21 January 2021 - 04:56 PM

Great thanks Adam, I'll try and flush it with water first then and then go for 33%, cheers

 

I wouldn't bother.  Just drain as much as you can (use the bottom rad hose).  Top rad hose will help too.


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#6 Badgers

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Posted 24 January 2021 - 05:04 PM

I wouldn't bother.  Just drain as much as you can (use the bottom rad hose).  Top rad hose will help too.

 

Great thanks, so I've now drained the system and replaced the coolant and thermostat but have noticed that the temp gauge seems to get to 90 really quickly now - for instance I started the engine at night when it was pretty chilly and just left it to idle and the gauge was at 90 in 9-10 minutes whereas it used to take 3-4 mins more previously - is there something wrong as I would have thought with nice new coolant it would actually take a bit longer than before to get to 90?



#7 gerrywac

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Posted 24 January 2021 - 06:17 PM

If you buy ready to use coolant to a VW spec then it should res h the temo for your country but if you buy a concentrate then you may need to alter the amount of water to get the right frost resistance. Use the VW recomnended temp rating and follow the after market makers instructions on dilution to match.
Now that sealed pressurised cooling systems are the norm and top ups largely a thing of the past its very rare to hear of an engine freezing. If you srart lodkng coolant you should attend to it ASAP and if you delay should only use the coolant mix not just water.

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#8 gerrywac

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Posted 24 January 2021 - 06:28 PM

I wouldn't bother. Just drain as much as you can (use the bottom rad hose). Top rad hose will help too.

If you do this and upgrade the coolant spec to current then expect a surprise at the final colour.
Mine had factory orange G12++ and as it looked crystal clear I didnt flush when I went to the current purple G13.
Not sure what colour to call the result of mixing, definately not purple now, but no issues after 3 years

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#9 gerrywac

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Posted 24 January 2021 - 06:40 PM

Great thanks, so I've now drained the system and replaced the coolant and thermostat but have noticed that the temp gauge seems to get to 90 really quickly now - for instance I started the engine at night when it was pretty chilly and just left it to idle and the gauge was at 90 in 9-10 minutes whereas it used to take 3-4 mins more previously - is there something wrong as I would have thought with nice new coolant it would actually take a bit longer than before to get to 90?

What spec coolant did you refill with G13 or the older G12 (+ or ++)
Different types can draw different amounts of heat to warm up until the thermostat opens, after that all should be well and thd stat should keep it at 90C

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#10 Badgers

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Posted 24 January 2021 - 08:10 PM

What spec coolant did you refill with G13 or the older G12 (+ or ++)
Different types can draw different amounts of heat to warm up until the thermostat opens, after that all should be well and thd stat should keep it at 90C

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Thanks, I used Comma coolant but its same spec as original G12 and mixed it up to same ratio as specified in mkiv workshop manual that I found - the old coolant was same colour (pink/red ) so must have been G12 too so just seems strange the new coolant heats up to 90 around 3-4 mins quicker than old coolant, hopefully there's nothing wrong!



#11 ttg4l

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Posted 24 January 2021 - 08:11 PM

Thanks, I used Comma coolant but its same spec as original G12 and mixed it up to same ratio as specified in mkiv workshop manual that I found - the old coolant was same colour (pink/red ) so must have been G12 too so just seems strange the new coolant heats up to 90 around 3-4 mins quicker than old coolant, hopefully there's nothing wrong!

 

You say you did the thermostat too right? Could be just that the old thermostat was stuck slightly open when it was meant to be closed.



#12 adam-

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Posted 24 January 2021 - 08:23 PM

It's because you did the thermostat.


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#13 gerrywac

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Posted 24 January 2021 - 09:28 PM

Thanks, I used Comma coolant but its same spec as original G12 and mixed it up to same ratio as specified in mkiv workshop manual that I found - the old coolant was same colour (pink/red ) so must have been G12 too so just seems strange the new coolant heats up to 90 around 3-4 mins quicker than old coolant, hopefully there's nothing wrong!

If you fitted a new stat that will be the reason.




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#14 Badgers

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Posted 24 January 2021 - 11:55 PM

Ok thanks, thought that could be the reason but strange thing is I also have another 1.8T (long story) and when I compared that it takes around the same time to get to 90 when left to idle from cold start as my other one used to (~14-15 mins) before I changed the coolant and stat. So maybe the stat on that one is stuck slightly open as well although there seems to be no issues with it temp wise? Cheers



#15 ttg4l

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Posted 25 January 2021 - 12:25 AM

Wouldn't worry about it, sounds normal for an old stat. So long as it gets to 90 and stays there while driving, you shouldn't need to worry about it.



#16 Badgers

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Posted 26 January 2021 - 10:37 AM

Thanks, will stop worrying that the one with the new stat now gets up to temperature super quick! Cheers  :)







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