Green anti-freeze

[radiomarty]

My 96 MGF has green anti-freeze and I need to top it up - popped down to Halfords and they only sell Blue - Checked the bottle and it was Ethylene Glycol BS6580 so it seemed ok but having checked with the chap at the info desk he stated Green and Blue are different and cannot be mixed - I previously understood that the only difference was the dye so I need to source some soon. Can anyone clarify this and let me know where I can purchase the green type?

[kevocouk]

I have heard this too that they should not be mixed, i believe the recommended coolant is OAT, halfords sell this too.. may be worth draining it and refilling with a fresh load to be on the safe side.. buy 5l of the OAT concentrate and mix 50/50, that'll give you just about the right amount for a complete drain and refill.

[robbie1003]

it is a misconception that colour determines the type of antifreeze, maybe back in goodolddays it did when there were two types but it doesn't now. it is true you shouldn't mix certain types of coolant (the types escape me at the moment) as apparently they react causing a jelly type substance, not seen this myself in 30 years of accident repairs experience but it is known to happen. i have just changed my coolant in the f to makesure its oat as advised (usually use vw/audi or ford stuff as its readily available to me), the type i have used is from euro car parts, £11 for a gallon and is actually purple but atleast I know its right.

[diesel destroyer]

I was told by the man that built my engine to only ever use punk as the others have caused rot issues..

Why not dump all of the current coolant and install all new fresh?

Not a huge sum of money and an easy job

[adrianclifford]

I was told by the man that built my engine to only ever use punk as the others have caused rot issues..

Why not dump all of the current coolant and install all new fresh?

Not a huge sum of money and an easy job

And well worth doing, there are certain things that need to be done right. Why try something that you're not sure of when the remedy is readily available.

[Mike H]

I've posted this previously, but maybe it's time for a reprint

COOLANT

The commonly used OAT anti freeze (organic acid technology) contains a number of organic, acidic, corrosion inhibiters (hence the name!). It is critically important that this is NOT mixed with any anti freeze solutions containing methanol and, I think also, glycol. Bad chemical reactions can take place inside your engine! There are very strong warnings (see below) that OAT should not be used in engines previously using non-OAT anti freeze solutions, although very thorough flushing and running without any anti freeze for a short period to ensure removal of all non-OAT traces 'should' allow an OAT refill.

As I understand it (copied from a document in the bowels of my computer, but can't remember where I got it!):

Early vehicles up to VIN No: 512771 use UNIPART Superplus 3 Anti-freeze and Summer Coolant GEC1020 - 20 litre and GEC 1002 2 litre to protect the cooling system. The coolant is yellow/green in colour. CAUTION: No other ’universal’ or Organic Acid Technology (OAT) anti-freeze should be used with UNIPART Superplus 3 Anti-freeze and Summer Coolant. If UNIPART Superplus 3 Anti-freeze and Summer Coolant is not available, use an ethylene glycol based anti-freeze containing no methanol with non-phosphate corrosion inhibitors which meet specifications BS6580 and BS5117 suitable for use in mixed metal engines. To ensure the protection of the cooling system against corrosion, these anti-freezes must be renewed every 12 months.

Vehicles from VIN No: 512772 to Vin No: 520012 use UNIPART AFC Longlife Anti-freeze and Summer Coolant AFC GEC6025(25 litres) to protect the cooling system. The coolant is blue in colour. CAUTION: No other ’universal’ or Organic Acid Technology (OAT) anti-freeze should be used with UNIPART AFC Longlife Anti-freeze and Summer Coolant. If UNIPART AFC Longlife Anti-freeze and Summer Coolant is not available, use an ethylene glycol based anti-freeze containing no methanol with non-phosphate corrosion inhibitors which meet specifications BS6580 and BS5117 suitable for use in mixed metal engines. To ensure the protection of the cooling system against corrosion, these anti-freezes must be renewed every 12 months.

Organic Acid Technology (OAT) anti-freeze GEC5025 (25 litre)
Vehicles from Vin No: 520013 use Unipart OAT (XLC) coolant which is Orange/Pink in colour. Vehicles using OAT anti-freeze are identified by a label attached around the expansion tank filler neck. CAUTION: The anti-freeze used in the cooling systems of later cars contains OAT corrosion inhibitors. This anti-freeze must not be used with any other anti-freeze and must not be used as a replacement in cooling systems which previously contained anti-freeze not of this type. Use UNIPART OAT Anti-freeze and Summer Coolant or any ethylene glycol based anti-freeze (containing no methanol) with only OAT corrosion inhibitors, to protect the cooling system. Only anti-freeze containing OAT corrosion inhibitors should be used. Do not top-up or refill cooling system with any other type of anti-freeze. In an emergency, if anti-freeze to this specification is not available, top-up the cooling system with clean water only, but be aware of the resultant reduction in frost protection. The correct anti-freeze concentration must be restored as soon as possible.

[Rob Bell]

An excellent post Mike, thanks!

What this boils down to (unintended pun, sorry!) is "if in doubt, don't mix, flush and refill with fresh antifreeze/coolant of the correct standard"

[radiomarty]

Many thanks all for your replies - I will heed the the good advice - drain and replace.