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Coolant advice. Getting the van sorted after 2 years after i had a stroke.

Posted: 05 Oct 2026, 19:14
by djhammy
HI everyone hope you are all well.

I've been awol after a stroke 2 years ago that destroyed my balance centre among other things. I am though recovering better than i could have hoped and getting the T25 back up to scratch slowly.

Full service completed  last week and running lovely, Thats when my rewiring brain went into confusion mode. I've lost a lot of memory so please forgive me if this makes me sound like a complete novice again. 

 Hoping you can help and clear my mind before i allow a garage to replace the G13 Coolant/anti freeze after 5 years.

I have purchased 2 x Quantum G13 from Brickwerks along with 2x 5 ltrs distilled water enough for a 50-50 mix and for the 16/17 ltrs required for the VWT25 i believe.

 They always allow me to supply my own service parts and anything that needs replacing.  A lesson learned the hard way way back thats served me well since. 

Ive had this procedure done many times in the 30 years Ive owned the  van but was slightly worried by the conversation i had with the usual  mechanic in Southampton a few days ago after a full service. Hes always done a superb job never ever had to worry. 

i mentioned that the 2 x 5 ltrs of G13 and 2 x distilled water were stored in the van for him to use. 

He said he wouldnt need the water and would put the G13 in neat and should only need 10 ltrs to do the change (Instant alarm bells) went into temperatures it could go down to etc

Could well be my confused bonce getting this all wrong and maybe he was thinking it was premixed but this isn't right surely. .This doesn't sound like a full replacement and flush out how can it be if it holds 16-17ltrs.

I said said i'm sure concentrate is designed to be diluted and surely wouldn’t have the heat dispersion properties required. . I haven’t returned yet to discuss booking in until i get some info clear in my head.

So if any of you can confirm either way the following is be so grateful. 


Is G13 5ltr concentrate designed to be diluted and not used in concentrated form.

Is a 50-50 mix with distilled purified water ok and if so can i premix this and use to replace the old coolant/anti freeze. The instructions differ all over but says on the packaging to fill will clean water first then add the required amount of concentrate.

Thank you all and its good to be almost back. 

Hammy. 

Re: Coolant advice. Getting the van sorted after 2 years after i had a stroke.

Posted: 05 Oct 2026, 19:37
by mioba
He needs to drain it all. Rinse it out proper so its just clean water in there.
then drain it again.
He then needs to add 8.5 litre of the neat coolant and then fill with water to complete.
He wont get it all out thats why he must rinse, drain, rinse, drain till it drains clear.

Most importantly is that you are getting well. Be blessed!

Re: Coolant advice. Getting the van sorted after 2 years after i had a stroke.

Posted: 06 Oct 2026, 06:58
by Alfredo
Maybe this page on the Quantum website will help?

https://quantum-oils.com/en/product/ant ... ncentrate/

Re: Coolant advice. Getting the van sorted after 2 years after i had a stroke.

Posted: 06 Oct 2026, 09:30
by cobblers
The way I've always done this is to flush the system with tap water with the rad hoses off to clear the old stuff out.
Then pour 8 litres of G12 in then top up the rest with plain water giving about a 50% dilution.

Re: Coolant advice. Getting the van sorted after 2 years after i had a stroke.

Posted: 06 Oct 2026, 18:28
by mioba
If you want to make the flushing easier. Remove the stat. when flushing rinsing.

Reinstall when doing the coolant part.

The coolant housing will deform on removal so have a other spare.