Does anti freeze have shelf life ?

[63v8]

I am going to get some Comma super coldmaster coolant for my RV8  engine but have found 5L of 5 Star blue anti freeze in the back of a cupboard. It's unopened but I must have bought it over 10 years ago and not sure if it's OK to use. I was thinking of using it to fill up the system to get the car back on the road put a few miles on it to clean out the system then drain it and replace it with new Comma.

Just not sure if there is a shelf life for safe use.

[dreadspeed]

Id just dump the old anti freese buy some cooling system cleaner put it in drive it flush it it out the add new anti freeze. no risks taken for the sake of a few quid

[discostew38]

I can't see why it would go bad?
I've got two cars I've had for a very long time and I'm the second owner on both
In the time I've had them they've not had any coolant work and I can't think they would have before my ownership
So that would mean the coolant currently in them is going to be 20 years old and I don't have any issues

[kevins]

Always wondered about this, most manufacturers say change it every 2 years to maintain corrosion protection but there is no shelf life on tha can, and surely the mileage you do must be a factor.

[63v8]

I found some tech info for some blue Glycol anti freeze on sale which said the usual 2 years life in car, but also said it had a shelf life of 3 years. So I will leave my 10+ year old in the cupboard full of new but very old stock you find when looking for something else you need.

[ChasR]

I've had anti-freeze go bad before. I can't remember exactly what went wrong, but it was certainly different to fresh stuff I bought. IIRC it became lumpy etc.

Also, I wouldn't get that Comma stuff. I'd only use Comma G48 ; it's about the only IAT coolant I've seen that has inhibitors that actually work without going to an OAT coolant, and I've probably changed coolant too many times now on cars. It's also an OEM coolant for BMW and until Mercedes and Porsche started supplying OAT only coolant, it was the choice of coolant for them as well.

[63v8]

I've read to keep away from modern spec coolant in old ally engines like the Rover V8 and use old school ethylene Glycol with no additives like the Comma super coldmaster. I have found some Granville sub zero Blue locally one place being The SL shop in Statford upon Avon who recommend it for Mercs and other classic cars.
www.theslshop.com/parts-shop/granville-sub-zero-blue-antifreeze-summer-coolant-concentrated-5l.html

[63v8]

Halfords stock all the fancy new Comma coolants but not the Super Coldmaster. Asked if they could order some in and they said no only what they stock. Strange as I have ordered a 14 inch K&N air filter from them as a special order in the past. Phoned a local old school type motor factors and they do have the Comma Super Coldmaster in stock so will get it from them.

[ChasR]

I don't mean to sound nasty but I do wonder if the SL shop recomends the Granville due to the cost.

Even on trade, G48 concentrated for 5 litres is £30; that's not alot of margin, and can soon make a coolant change pretty pricey. But it's the only IAT coolant I've used which hasn't caused silt/rust in a cooling system in two years of use, and that includes cars where I have flushed the block and change radiators on cars. I've used prior to that Comma Blue from GSF, Unipart SuperBlue (that was a waste of money), Halfords Blue coolant, and a couple of other blue types.

G48 has treated me very well; cars I've bought with it in also seem to have little to no rust present in them.

OAT is fine but the application has to be considered carefully. The TLDR version is this:

-IAT coats stuff inside an engine with a protective layer. Phosphate is brilliant here but it scales with hard water. So in the UK other products do this job. However, as time goes on, these protective coatings/inhibitors go bad, which is why the water becomes rusty and the coolant becomes nasty and gloopy.

-OAT works differently. It attacks any rust forming in sight. This is one reason why OAT coolants need much less changing. However, on cars which haven't seen regular coolant changes and the mating faces are corroded, it can cause leaks. This active process can also attack solder, which is why OAT isn't genenrally recommended on cars with brass or copper radiators. But the jury is out there on later soldered stuff being fine ; buses for example are meant to be copper rads still, but they used OAT.

Then you get into some rubbers swelling which som coolants. This is one reason why you get manufacturer specific coolants these days, and that's before you consider that different engines will have different alloys between them .