A long time ago choosing the correct coolant for a car used to be easy.  Water.  Then along came glycol based antifreeze like Prestone and it was still easy- put the green stuff in.  The situation today is considerably different with Blue, Green, Pink, Red and even Orange coolants.   Generally the colors indicate a different standard, but you can’t count on the color alone any more.

According to Aston Martin the coolant in V12 engines should be changed every Five (5) years as part of your annual service.  The question is – Changed with what?   Read on to learn more.

What Does Aston Martin Recommend?

As always with these questions I start with looking at what engine coolant Aston Martin actually recommends.  Doesn’t mean its the only or best solution, but its certainly the safe solution and the standard that we’d want to meet or exceed.

If you reach over to your Glove Box and open the  Owners Manual to the Fluids and Capacities page they list it there:    Havoline OAT coolant at 50% concentration- 15 liters.

I also checked the official Aston Martin Workshop manual Section 3.03 Cooling System and they also listed the same requirement of 50% OAT Coolant.  It’s interesting to note they do not specify a brand here which leads me to believe we have some latitude here on choice.

The also specify the Service Interval.  Every 150,000 mile OR 5 years, whichever comes first.  You should consider this as gospel whether you drive your car 20,000 miles per year or 500 miles.  Its a time based degradation of the chemicals in the coolant.  When was the last time you changed the coolant in your Aston?

What is OAT Coolant?

Now that we know that they want us to use OAT coolant, what is it?

To start with it’s not the traditional Green stuff  you might think of when it comes to coolant used in most cars before the 1996.  That’s a Glycol based coolant, and as noted above we really, really, really don’t want to mix any Glycol based coolant with our OAT coolant.  Seriously – goop results and you’ll be in a world of hurt damaging the engine.

OAT stands for “Organic Acid Technology”.   You can learn more about it in detail over here at Wikipedia.   OAT coolants are generally more environmentally friendly than traditional glycol based coolants.    While the antifreeze aspect of the coolant never really degrades, the added corrosion inhibitors are consumed and need replenished periodically.   Most OAT coolants have corrosion inhibitors designed to last at least 5 years, which is what Aston’s recommendation for fluid change is based upon.

Interestingly the article notes potential differences between US, EU and Japanese automakers chosen coolants – “Traditionally, there were two major corrosion inhibitors used in vehicles: silicates and phosphates. American-made vehicles traditionally used both silicates and phosphates. European makes contain silicates and other inhibitors, but no phosphates. Japanese makes traditionally use phosphates and other inhibitors, but no silicates”    Based on this, we might expect to find that the Havoline OAT specified by Aston uses Silicates but no phosphates.  My guess this is more about environmental regulations than coolant performance.

OAT Coolant is generally Orange in color (but this isn’t an industry standard rule).

A word of caution here, the market is crowded with new coolants that are POAT and HOAT technologies.  These are NOT the same and I wouldn’t necessarily consider them interchangeable with OAT.   Unless someone can show me Aston suggesting otherwise, I am sticking with the search for OAT.

OAT Coolant is often synonymous with Dex-Cool that was formulated for GM cars.  Dex-Cool also seemed to get a bad reputation in the GM world because during the early years after its introduction GM had issues where the chemical composition of Dex-Cool interacted with the materials used in some of their engine gaskets causing a sludge to occur in certain conditions.  Those days are long gone and I would move past that when considering selecting a coolant in a modern Aston.  OAT coolant is still OAT coolant even if they say it is Dex-Cool compatible on the bottle.  OAT/Dex-Cool coolants are NOT recommended for use in older engines (pre 1996) for this reason.   Our Gaydon era cars are OAT all the way!

Havoline OAT Coolant

Important first item to note.  This coolant is NOT bespoke to Aston Martin and there is no magical formula that was whipped up for the DB9.  This coolant is used in many other cars.

Havoline is a brand offered by Chevron in the USA as “Havoline Xtended Life Coolant” or abbreviated as “Havoline XLC”.

You can find the Product Data Sheet for it here.    Some interesting details include:

• Meets Ford spec WSS0M97B44-D
• 150,000/5 year system protection
• Is recommended for:
  • Ford Vehicles post 2003
  • European gasoline automobiles
• At 50% concentration
  • Boiling Protection 265°F (129°C)
  • Freeze Protection -34°F (-37°C)
• Color Orange

Since Ford owned Aston at the time the Gaydon era cars were designed, Aston’s specs typically mirror Ford of that day.

I called my local official Aston dealer to ask them what to use.  Over the phone they told me I could just go buy a bottle of Havoline Extended Life Coolant (Orange) locally if I could find it.  They kindly even sent me pictures of the front and back of the 1 liter concentrate bottles they sell so I could be sure to get the right stuff.   This was super helpful to nail down that it isn’t some bespoke fluid, and merely a fluid they are buying from someone else.   If you look at the specs on the back of the bottle, it has the SAME references that its for Ford, Chrysler and GM vehicles, and lists the exact same Ford spec WSS0M97B44-D.  Says these were bottled in Belgium, so Aston is shipping this stuff across the pond to the USA.  Might explain part of the reason it is 6x more expensive.   This is the exact same stuff we can buy at the local auto parts store.  Convince yourself if you like, here is the front and back of the label the Parts rep sent me.

Premix or Concentrate?

Generally manufacturers make their coolants available in one of two forms.

• Concentrate – where you are required to add the correct amount of water and can make the exact ratio you want.
• Premix – where they typically add water for you and the mix is already 50/50 in the bottle.  You can just add directly to the cooling system.

If you use concentrate it is highly recommended that you mix with DISTILLED WATER, not tap water.  Tap water may contain minerals that will affect the coolants performance, so using distilled water that you can source at your local grocery store is the best option.  You’d need 2 Gallons of distilled water to go with 2 Gallons of concentrate,

Why the options?

Shipping weight for one thing.  If you were ordering online and it has to be shipped to you, you only need to purchase Two heavy one gallon bottles of concentrate rather than four bottles of premix.

Another factor might be if you want to customize your mixture to a value other than 50/50.   While a 50% mix is good for temperatures as low was -37° C (-34 °F), in a colder climate you can vary the ratio to 60/40 where 60% is coolant, 40% water.  This will now be good for temperatures as low was -52° C (-62 °F)

Generally concentrates offer a lower total cost per gallon once mixed.   If purchased in store, a gallon of concentrate might cost $20 USD, and a gallon of premix might cost $17 USD.   If you make a 50/50 mix with the concentrate you’ll get two gallons for about 40% cheaper (about $21 USD including the $1 cost of a gallon of distilled water from the local grocery store) than the cost of buying two bottles of premix (about $34 USD).   Don’t forget to factor in any shipping costs if you buy online.

If you are fine with 50/50 and are walking into the local autoparts store to get yours, its likely most people will just pickup the convenient premix option.  Less fuss and it’s ready to use.

Cost

Coolant is generally not very expensive (if you buy it someplace other than a dealer).  Here is what I found searching for Havoline OAT coolant from various sources:

• USA Online or in Store
  • Havoline is sold as a Chevron brand in the USA
  • Concentrate – 1 Gallon – $15.74 USD at Napa Autoparts in store
    • (available for online ordering, but shipping is extra)
  • Premix – 1 Gallon – $22.40 USD Online at Amazon with free shipping
• US Dealership
  • I called my nearest Aston Dealership and asked for a price for Coolant.   I was told a one liter bottle of concentrate is $23.82 USD!  For a full flush you would need 8 of these little guys costing $190!
• UK
  • Havoline is sold as a Texaco brand in the UK.
  • I can’t get exact pricing very well for this, but it seems that you can get a 1 litre bottle of Havoline XLC 50/50 premix from ebay.co.uk for about £9.99.  This adds up since you’d need 16 of them.
  • If you are a reader in the UK has a good online source for this please leave it in the comments below and I will share with everyone.

A bottle of distilled water at my local grocery store was $1.09 USD.

Therefore you can pickup 2 gallons of concentrate from Napa Autoparts in store for $31.48 USD and spend another $2.18 USD on 2 gallons of distilled water, and for just under $35 USD you have the 4 gallons (about 16 liters) of 50/50 coolant you need.   Not very expensive at all.

Aston1936 Recommendation

As I researched this I also asked Mike from Bamford Rose in the UK. Bamford Rose is an independent specialist dedicated to Aston Martin service.  Mike’s opinion was to just get any good quality brand OAT coolant and mix to the right concentration and to flush it every 5 years (or pragmatically with a major service).

Since Havoline Extended Life OAT Coolant is available in the UK, US and Canada that’s my recommendation.   Buy it in your local autoparts store, online or through your local dealer.  Since its relatively inexpensive (for me sourcing at the local parts store was $35 USD all in to make 16 liters) and you only need to change your coolant every five years, I don’t see any reason to explore cheaper or alternative options.

If you are in a region where you can’t reasonably source Havoline OAT, then I would recommend selecting whatever premium brand of Extended Life OAT coolant is available locally to you.

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What Coolant are you using?

It’s always interested to learn what other are using.  That feeling of Safety in numbers I guess.    Please take a moment to share what coolant you are running in your Aston Martin.

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Video

If you’d like to seem me musing about Coolant and having a discussion about some of the factors with Mike from Bamford Rose please check out this video.