Engine coolants

[Kram]

I'm aware that many modern cars use a fancy organic acid type coolant that should not be mixed with the bog standard etheylene glycol. I've also heard and read some.horror stories of the newer OAT type, eating engines away.

Asked in a shop and they tell me, my Mazda 6 GH 2009, should be OAT, red stuff.
The current fluid is 100% dark green, suggesting I have the old style. However I'm aware its just a dye and there might be brands selling green OAT, just to confuse things...

I am thinking to drain, flush it out well, and refill with 50% EG.

Any easy way to check whats actually in there?

 

[ajlelectronics]

The clue to the coolant type required, is what your cooling system is built from. If you have soft metals, solder, copper etc then OAT is bad news. However if your vehicle is mostly plastic, then OAT will be fine.

 

[Kram]

Automotive cooling systems very rarely use copper (expensive) or solder (sht). The only type I'd exclpect either would be old British manufacture, or steam engines! Modern engines after 1990? and radiators are generally aluminium, possibly with some steel bits thrown in for the water pump, oil cooler and thermostat, please correct me if I'm wrong.

OAT was invented as a cost saving, engines-scrap-if-you-service-incorrectly type thing. Ford and their dealers loved it, if I remember correctly.

 

[Ubique]

There are a few types of OAT, some with or without silicates - that's the bit that matters the most in the 'engine-eating' category - it goes without saying that mixing different types is not a good idea, some BMW's use a green OAT, just to confuse things, MB used to have a blue OAT....

 

[ajlelectronics]

Automotive cooling systems very rarely use copper (expensive) or solder (sht

All proper cars do! It's just the modern junk that uses plastic / aluminium. I have certainly seen jellyfied coolant passages in engines that have had OAT put in erroneously.

 

[bricol]

Yep, older cars with soldered bits, and people adding soldered pipework to fix leaks etc - as far as I'm aware, the copper bit isn't the problem, its the solder that vanishes.

The OAT stuff is in my Dodge - ten year life.

 

[Ubique]

Your coolant should be G12+, which is silicate, borate, nitrite, and phosphate-free. Regardless of what is currently in, that is the correct spec. I'd suggest flushing with de-ionised water after draining as much as possible, the maximum concentration should be 63% OAT, although most places will mix with de-ionised water to 50%, some places will use tap water....

 

[Trevorleach]

Your coolant should be G12+, which is silicate, borate, nitrite, and phosphate-free. Regardless of what is currently in, that is the correct spec. I'd suggest flushing with de-ionised water after draining as much as possible, the maximum concentration should be 63% OAT, although most places will mix with de-ionised water to 50%, some places will use tap water....

I have been using tap water for nearly 4 decades on cars and trucks, 10 years of that was dealership work as well.
Always 50/50, thought getting that bit through to the drivers can be hard work.

 

[Ubique]

VWG always mandated de-ionised water, if it wasn't booked out on warranty jobs, the claim would be refused. I suppose it depends on the water hardness, some areas will be OK and TBH, by the time it's starting to block up things like heat exchangers, then it'll be well out of warranty anyway and be put down to age or 'wear & tear'.
I always dilute mine with de-ionised water but then I have litres of the stuff, surplus from VWG warranty jobs...

Service coolant top-ups were and are always tap water, irrespective of brand.

 

[Kram]

All proper cars do! It's just the modern junk that uses plastic / aluminium. I have certainly seen jellyfied coolant passages in engines that have had OAT put in erroneously.

Which parts of a modern car include copper?
The only part I can remember on older cars is the interior heat exchanger was usually brass. I'd be suprised if they were not all aluminium now.

Tap water has a lot of minerals which can make it somewhat galvanically conductive between dissimilar metals. I would always use deionised for filling.
Tap water is generally ok for flushing, if you get it all out.

 

[Onoff]

I only put proper Honda OEM silicate free coolant in my lad's Jazz.

 

[ajlelectronics]

Which parts of a modern car include copper?

I said proper cars, not moderns.

 

[Ubique]

I said proper cars, not moderns.

I appreciate you don't 'like' anything from probably late 1980's onwards, but things move on and it's not really helpful or relevant to harp back to your 'golden age' in terms of this discussion.

 

[minimutly]

Yep, older cars with soldered bits, and people adding soldered pipework to fix leaks etc - as far as I'm aware, the copper bit isn't the problem, its the solder that vanishes.

The OAT stuff is in my Dodge - ten year life.

ARE YOU SURE IT'S 10 YEARS?
Sorry for the caps, but mostly it's 5 years, and if you leave it too long it eats core plugs etc..

 

[knighty]

slightly off topic... I thought the red stuff was good for aluminium where the blue stuff wasn't as good?

water chiller on a machine at work... I put the red stuff in... have I goofed?

there's copper and aluminium and stainless in the system that I know of... it was running pure water and full of corrosion when I got it, cleaned it out the best I could and refilled with some red antifreeze in

flow rate is down, I assumed I'd missed some corrosion or something, I've been trying to decide what to run in it to try and flush it out.... :-o

 

[Ross365]

When the more diverse coolants were introduced, they colour-coded them, but there was no one to police the system and colour is not a dependable guide now. There are "universal" coolants available but I've never used them. My approach is that Honda coolant goes in the Honda car and Toyota coolant goes in the Toyota car and both cars are totally wonderful .

 

[Domdom]

I don’t really understand the chemistry of the various coolants but my A6 had suffered from mixing the wrong stuff in. It was all like a jelly and the cause of overheating under load. I just flushed it all through with a hose, which wasn’t simple I might add, then refilled it with tap water. I ran it for a couple of days like that and then flushed it again, finally filling with G12. It’s been fine ever since.

 

[dobbslc]

I use genuine Toyota coolant in the Surf as it's not that much more expensive than Halfords stuff.

 

[Keithmac]

I've only ever seen the Pink OAT coolant, interesting that there are different colour OAT coolants in circulation.

 

[GRW]

I need to change the coolant on my 2008 Renault Master Camper this autumn really for peace of mind - it'll be 2 years this November.

I've been wondering whether or not the coolant will be something I'm unfamiliar with (I.e. not Ethylene Glycol ) as its a reddish colour in it now.

Something else I need to get into & doubtless buy more "different stuff to put in it!

This thread has stirred my poor brain into action.