Yellow Triumph Coolant Mixing With Original Green Coolant

Don't mix them. If you look at the description online of companies selling the new stuff, it says:

Triumph D2053 OAT is coloured orange compared to the Triumph HD4X OAT which is coloured green. The two coolants MUST NOT BE MIXED TOGETHER as this could result in a reduced cooling performance and a reduction in corrosion resistance.
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When I changed my coolant using the new stuff I completely flushed the system out with water first. (In fact I actually changed the coolant twice as I realised to get coolant out properly you need to run the bike until it gets up to temperatue and the thermostat valve opens).

Is this the first time you checked the level? Could it be that it wasn't correctly full when you got the bike?

If you know it's gone down I'd be asking myself where the coolant has gone, it's a closed system so shouldn't disappear - though I'm sure no expert on these things, perhaps someone else will chip in here?

 

Perhaps it's the old stuff, what's the part number on it? Old coolant is A9610050, new is T4007777.

Of course, if you're doubtful about the history of the bike, you can't know if what's in there is the original OEM stuff or not.

 

I've no idea what the price of "Triumph" branded coolant is but I've used Halfords OAT coolant in the car and the bikes for years. The name isn't important, it's the compatibility specs that count. When I fitted a new rad to the ZZR some years ago I was advised to use Kawasaki's recommended coolant, can't remember which brand, may have been Motul or Motorex but it was way more expensive than the Halfords stuff. Feck that, an engine is an engine!
I've thought of switching to the Evans waterless stuff a few times but the benefits vs cost equation always killed it for me. It may last the life of the engine and have a far higher boiling point but the long life OAT stuff works just fine and you can change it several times over for the same cost.

 

Ah bugger. Not that I have had any issues so far since changing the old green HOAT for new pinky orange D2053 coolant, but now thinking about it when I flushed out the system using distilled water, I ran the engine for a few minutes but not sure if it will have got hot enough to open the thermostat.

So I guess there’s a chance there will have been a bit of the old stuff left in the water jacket that’s now mixing with the new stuff when the bike is being ridden and fully up to temp.

Should I be concerned? I read about different coolant types forming a gel when mixed, which obviously isn’t good. But the only thing said about the old and new Triumph coolants not being mixed is that it will result in “less cooling performance and less corrosion resistance”, which I might be able to live with until the next scheduled coolant change?

 

I wouldn't be worried. You can drain and flush the system successfully with a cold engine. You can't safely drain the system of a hot engine anyway because it's pressurised and potentially 100 + deg C. Thermostats usually have a small bleed hole, sometimes with a jiggle pin, to facilitate draining and filling a cold engine. Don't waste money on distilled water either. Even if you live in a hard water area the amount of contaminants in such a small amount will be negligible. JMO