Club 80-90 Forums

Hi. I have three issues here which hopefully someone can help with:
--Does G10 coolant exist?
--Is it OK to mix G10 coolant with G12+ ?
--Why is my coolant disappearing from the top up tank?

Firstly, I have read the FAQ and other topics on coolant issues but none of them mention G10, which is what I believe is in my coolant system (it's blue) and whether this is ok to mix with G12+ (which is pink), hence the new post. Hopefully someone can help me get to the bottom of this...

Engine is a 1990 t25 1.6td, with 100k, and a new cylinder head 8k miles ago.

Just bought the van from a guy who gave me a bottle of G12+ which he said "is not G12+, it is G10", and sure enough he had written G10 on it. The contents were blue. It was a half used bottle. He said that it was "very important" to always use this same stuff.

The top up tank is empty, so I put some of this G10 stuff into the top up tank when the engine was cold to halfway between min and max. A hundred and fifty miles later and it is empty again. First question: Am I right in thinking this shouldn't just keep disappearing so quickly? Or do T25's just do this?

I took the van to a garage to get coolant system checked for leaks. System was pressure tested but no leaks found. Main water bottle was replaced (in engine bay) and a couple of clips. Will wait and see if this does anything.

However, my second question is this - the garage topped up the system with pink G12+ and I am a little worried as I have read that mixing different types can cause it to become very acidy and potentially cause a bit of damage...I have not been able to find any information on "G10" which is what I was told is in the water system at the moment (blue stuff), and whether or not this mixes with G12+ (the pink stuff). I am confused. Do I need to get the system drained out and all the same put in or not? Does G10 even exist (or did it once upon a time?) All I can find online is G11 and G12...

Any advice greatly appreciated!

Cheers.

as far as im aware g10 was superseded by g11 in the eighties.so the stuff you have is probably well past its sell by date.if i was you i would be doing a full coolant change.using modern coolant.as for the water in your top up tank being used up.this only gets used if your expansion tank needs it.so you must be losing water somewhere..

That old G12 chestnut...

Any quality brand coolant is fine.. but yes there are reports that "pink" and "blue" should not be mixed but thats rather fuzzy...

No amount of "G12+" or whatever is going to prevent/reverse the corrosion that will enevitably have occured over the last 20 years...

There are many places that the coolant could escape from... and a telltale blue ish "fur" in the area will show this... but not always easy to identify.. places I would start are any pipes that have been disturbed during the head change.. any hose clips that are pressing on compressed rubber wont be as effective.. has the system been bled again recently? could be trapped air coming out and thus pulling coolant back in...

Have a look in the WIKI on cooling system..

Oh and please fill out your location in your profile as we may be able to suggest a T25 specialist or experienced member near you

Cheers guys.....will check as you said, much appreciated! Have been worrying that my water system will be turning to acid juice!

In the service history I have the cyclinder head was replaced 2 years ago by a vw audi specialist, and 6litres of a antifreeze were used so I was assuming it was a full change but maybe not. There was a little bit of sediment in the old bottle when this was replaced (yesterday)...

Am in the surrey area. If you can recommend anyone to do the above that would be great.

Thanks again...

go see steve at http://www.eastfalia.com" onclick="window.open(this.href);return false; he his in your neck of the woods and if he cant do it he will point you in the dircection of someone reputable who can

Not sure where you are in surrey but this place is run by an old mate who served apprentership in VW main dealers and has worked on vw's ever since.
Does lots of work on T25''s and is a good bloke.
His name is Lee and this is his place.....

Witley Station Garage Ltd
Station Approach
Wormley, Godalming, GU8
01428 685330‎

6 litres of coolant isnt enough... the system holds approx 17L... so either the ready to use stuff or use the concentrate that you dilute... normally this isnt diluted more than 50/50... use de min water, or if you are lucky and live in a soft water region, use that.. But DO NOT use water from a water softener (where you use salt)...