Flushing OAT coolant out of engine

For my bike, I'll pay extra for a decent make which actually says it's OK with all metals. It doesn't hold much.
For my car, what's in there might just outlive the car anyway!
For the boat, we have a backlog of the old blue stuff to use up.
 
Many thanks to all for your advice, especially to Thinwater. I am currently using Halfords OAT. I just wanted something that would comply with the Beta /Kubota requirement for mono ethylene glycol extended life. I had no idea that I was entering a world of acronyms and voodoo-speak from so many companies. Even their product data sheets fail to give the chemical constituents.

So: any advice on what to add after I've flushed the current stuff out of the system would be much appreciated. Given that it will be there for a year or so, I'm not too worried about cost. (In fact, I may just buy from Beta, as I do with other spares. What a good idea!)

Many thanks to all.
 
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Dull Spark said:
Many thanks to all for your advice, especially to Thinwater. I am currently using Halfords OAT. I just wanted something that would comply with the Beta /Kubota requirement for mono ethylene glycol extended life. I had no idea that I was entering a world of acronyms and voodoo-speak from so many companies. Even their product data sheets fail to give the chemical constituents.

So: any advice on what to add after I've flushed the current stuff out of the system would be much appreciated. Given that it will be there for a year or so, I'm not too worried about cost. (In fact, I may just buy from Beta, as I do with other spares. What a good idea!)

Many thanks to all.
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Halfords OAT is fine, especially if you can pick it up during their sale period.

Richard:encouragement:
 
The Beta manual does indeed only say long life, which usually means OAT. But I believe, correct me if i am wrong, that OAT coolant is slightly alkaline so shouldn't be used in engines that have brass or cooper in the cooling system which is why I have always used the blue 2 year life coolant in small boat engines. What I find strange is Beta recommending a long life coolant but also recommending the coolant is changed every year or 750 hours in their service schedule. An email to Beta may clear things up.
 
black mercury said:
The Beta manual does indeed only say long life, which usually means OAT. But I believe, correct me if i am wrong, that OAT coolant is slightly alkaline so shouldn't be used in engines that have brass or cooper in the cooling system which is why I have always used the blue 2 year life coolant in small boat engines. What I find strange is Beta recommending a long life coolant but also recommending the coolant is changed every year or 750 hours in their service schedule. An email to Beta may clear things up.
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I suspect that the annual change interval is simply a precaution against seawater ingress and build up. There's no way that any type of antifreeze will lose its anti-corrosive properties in just 12 months.

Richard
 
Why do you particularly want to get rid of OAT coolant? (I'm not familiar with what it is apart from apparently being a modern efficient coolant? Does it have negative aspects?

What is OAT coolant?
How do I know if I am using it?
Do I need to know I am using it?
 
Old Bumbulum said:
Why do you particularly want to get rid of OAT coolant? (I'm not familiar with what it is apart from apparently being a modern efficient coolant? Does it have negative aspects?

What is OAT coolant?
How do I know if I am using it?
Do I need to know I am using it?
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Oat coolant uses organic compounds for the anti corrosive properties of the coolant. It is less harmful to the environment, lasts longer, some claim it's better for rubber hoses, except silicone hoses, and slightly better heat transfer. The disadvantage is that long term it can attack copper/brass/solder used in copper radiators. Problem is only some Oat coolant will have the additives to cause this depending on the manufacturer. So some Oat coolant will be ok, some will not. Also some Oat coolant can react with the two year stuff if it isn't flushed through and create a black mess, again depends on the manufacturer.
Unfortunately there is no standard colour for the different types of coolant, so looking at the colour tells you little.
Unlike a car were you simply give your reg to the motor factor and they tell you what is recommended you can't do that with a boat. You will just have to go with what the manufacturer says. But keep topping up with the same type as what's in there. If you are changing/flushing the coolant in a boat engine I would play it safe and use the two year coolant unless the manufacturer states otherwise. For example in Caterpillar engines I would always use genuine Caterpillar coolant.
Recently manufacturers have brought out a hybrid coolant that is supposed yo be safe in older and newer cars, it may be the way to go.
For some useless info, many years ago in Russia they used vodka instead of antifreeze in their cars because it was much cheaper.
As you can see not all coolant is the same, not all Oat coolant is the same, and you can't go by the colour of the coolant to tell you what type it is. You can have blue, pink, red, purple, green, or clear if it's vodka.
 
lw395 said:
... Some OAT coolant is said to be not good with copper....
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Without backup that is rumor. Perhaps useless rumor. I've tested a lot of OATs and that is not a weakness.

However, if just a trace of seawater gets in there, cracking is a possibility. Also, some nitrited OATs (NOAT) in truck applications (CAB fabricated exchangers) can generate ammonia in situ, which is horrible.

I suspect there is a separate factor, such as one of these.
 
lw395 said:
For my bike, I'll pay extra for a decent make which actually says it's OK with all metals. It doesn't hold much.
For my car, what's in there might just outlive the car anyway!
For the boat, we have a backlog of the old blue stuff to use up.
Click to expand...

Has there ever been a brand that did not say it was OK with all metals? In the last 30 years?
 
black mercury said:
... But I believe, correct me if i am wrong, that OAT coolant is slightly alkaline so shouldn't be used in engines that have brass or cooper in the cooling system ....
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You are wrong.

ALL coolants are slightly alkaline, it is a matter of degree. Old conventional pH 10.5-11, most OATs 8-8.5. But the conventionals were always FINE on copper, just hard on aluminum and water pumps. THIS is what caused the change (the shift to alloy).

Follow recommendations unless you really want to get into the chemistry and the history. It is convoluted, and much or what you read about colors and formulations is just repeated urban legend.

[BTW, the great grandfather of OATs were formulas developed for the Rolls Royce aviation engines in WWII. Aluminum cylinder heads and superchargers creat6ed a need that did not spread to cars until ~ 20 years ago.]

The most important rule, however, is that there is no such thing as long life coolant in a marine application unless you are testing for sea water intrusion (chloride). Anything over 20 ppm makes the best coolant fail, and at 100 ppm, it will be worse than the cheapest coolant ever made. Adding trace amounts of chloride is how labs force premature failure for testing purposes.
 
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Confused? Yes I am! (But thanks for your advice.)

I thought that Halfords OAT was different from mono ethylene glycol, so decided to change it to the latter type. Is it really mono ethylene glycol but with OAT as well? If so, I'll just buy another few litres of Halfords and worry less about mixing two different types.

Given Thinwater's advice re possible saltwater, even a small residual of it would spoil any new antifreeze, so should I flush out with tap water or demineralised? (All getting a bit technical, but worth getting right if I'm going to leave it in for a couple of years.)

Many thanks.
 
Yes just use tap water to flush through the system. Ideally use deionised water with the new coolant if its concentrated, if its ready mixed you won't have to worry.
 
lw395 said:
In so many words?
Common OAT coolant such as the Halfords branded Comma product are labelled as unsuitable for older vehicles.
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The problem is not metals, it is compatibility with elastomers. However, the newer formulations have generally overcome these issues. I'm not sure why Halford still has that concern.

As for flushing... DON'T. There is no need, what so ever. You can only do harm. Just change the AF.

If you read the MSDSs you will see nearly all of these are based on 2-EH, making them decedents of Texaco's DEXCOOL.
 
The re are 'extended life' coolants such as Cummins NOAT which are EH free, for which claims to be better with elastomers and hose materials.
These ccoolants are good for very long times and you'd probably only change them if they became contaminated, in which case a rinse might be a good idea.
https://www.cumminsfiltration.com/NOAT

Some of the other premium brands cite BASF inhibitors.
 
thinwater said:
The problem is not metals, it is compatibility with elastomers. However, the newer formulations have generally overcome these issues. I'm not sure why Halford still has that concern.

As for flushing... DON'T. There is no need, what so ever. You can only do harm. Just change the AF.

The op is intending to flush out the cooling system to make sure all the old stuff is removed from engine and calorifier and to make sure there is no silt built up etc. How is flushing a cooling system with water going to cause harm? He doesn't intend to use an acid cleaner. Ac delco also don't recommended their Oat based coolant for older cars.
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