Which antifreeze?

VP offer a non-antifreeze inhibitor but say it should be changed every year as against 2 years for a/f, don't know why.
Sentinel in central heating is supposed to last indefinitely AFAIK.
 
Lazy Kipper said:
Do they reduce cavitation in the liners as well?
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Cavitation erosion of cylinder liners ! That's the lid off another can of worms.
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NormanS said:
Settled on the blue stuff.
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Two years later, how did this work out for you? Should be about due for another coolant change now. Heat exchanger still happy? Any problems?

My MD22 has 2 year old green Volvo coolant (Part No. 1141646) in it and while I'm generally happy buying Perkins parts and aftermarket consumables, I'm wondering if the cheap car coolant will do the job as well as Volvo's nectar of the gods. I'd really rather not be doing this anytime soon and if the pricey juice saves me the cost of a new heat exchanger, I'll happily buy it. But only if it's actually better :)
 
VicS said:
There are basically two types of antifreeze.

The conventional low silicate type ( sometimes called inorganic acid technology) is used in older engines

The "advanced", longlife, , "Organic acid technology", or OAT, type used in engines more recent than about 1994 ( and i think all Yanmar engines)

The colours can be a bit confusing ! Best go by the description and ignore the colour.

The two types must not be mixed. The corrosion inhibitors are different and not compatible with each other. (although it is possible to buy a universal topup mix)
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Some time ago Yanmar used a green coloured AF. As AF technology changed their recommendation was to move to the red long life OAT. (and by doing it sooner rather than later to improve on overall wear and tear).
The recommended AF is the Havoline long life concentrate available from Mobil petrol stations. If you've got engine hot water system then you should backflush to get all the green stuff out.
 
Yngmar said:
Two years later, how did this work out for you? Should be about due for another coolant change now. Heat exchanger still happy? Any problems?

My MD22 has 2 year old green Volvo coolant (Part No. 1141646) in it and while I'm generally happy buying Perkins parts and aftermarket consumables, I'm wondering if the cheap car coolant will do the job as well as Volvo's nectar of the gods. I'd really rather not be doing this anytime soon and if the pricey juice saves me the cost of a new heat exchanger, I'll happily buy it. But only if it's actually better :)
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Yes an ordinary car antifreeze will be perfectly satisfactory. Apart from special brews for specific manufacturers there are two basic types. The conventional low silicate type ( sometimes also called Inorganic acid technology , or IAT) for older engines and the organic acid technology (OAT), or long life, type for more recent engines
Volvo Penta #1141646 is the conventional low silicate type.

There is no standardisation on colours. Vovo use green and yellow. Halfords own brands are blue and red. Take note of the labelling , not the pretty colours.

Volvo recommend diluting the concentrate with distilled water except where the tap water supply is soft and low in total dissolved solids. ( details in the owners manual) Id expect Brighton tap water to be very hard so buying the antifreeze ready diluted may be a sensible option.
 
Bobc said:
+1. I use the pink stuff.
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While the "pink stuff" may or may not be sufficient, I can't accept the reasoning of "it's what the car version uses". That's fine for most parts, but not the cooling system. The key difference between a car engine and a marine engine is the heat exchanger, which is what the corrosion inhibitor in the coolant needs to protect (among other bits). So just because it's good for the car version does not mean it's equally good for the marine version with a large aluminium block that incorporates a raw water heat exchanger, exhaust manifold and coolant expansion tank.

And if the car radiator does fail, it's not only much cheaper to replace, but also can't end up leaking sea water into your engine block, causing major follow-up damage.

Things I've learnt so far:

- Both Volvo and Perkins specify ethylene glycol antifreeze only (2 year cycle), no OAT (even in the latest publications, not just the original ones where OAT was possibly too new).
- Both recommend a 50/50 or 40/60 (Volvo, optional) antifreeze/water ratio (using soft water, distilled water or pre-mixed coolant)
- Both highlight the importance of using the correct corrosion inhibitors (but do not say what those are :nonchalance:)

The Volvo part numbers are:
Coolant ready-to-use (green) 1141674 (5L)
Coolant concentrate (green) 1141646 (5L), 1141645 (1L) - mix 40% coolant with 60% distilled water.
Coolant system cleaner 21467920 (200g)

The Perkins part numbers are:
Perkins POWERPART Antifreeze 21825166 (1l)
Perkins POWERPART Antifreeze 21825167 (5l)
Perkins POWERPART Antifreeze 21825168 (25l)

I was hoping to find the Perkins stuff for less, but it doesn't seem to be available anymore, at least not where I've looked.
 
Bobc said:
+1. I've used Unipart pink stuff in mine (TAMD-22) for the last 4 years with no adverse side-effects.
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Any particular reason why you have chosen to use an OAT type when, AFAIK it is not specified. Like the colour? Believed it was "better"? Wanted a long life antifreeze to avoid changing every 2 years?


Yngmar said:
While the "pink stuff" may or may not be sufficient, I can't accept the reasoning of "it's what the car version uses". That's fine for most parts, but not the cooling system. The key difference between a car engine and a marine engine is the heat exchanger, which is what the corrosion inhibitor in the coolant needs to protect (among other bits). So just because it's good for the car version does not mean it's equally good for the marine version with a large aluminium block that incorporates a raw water heat exchanger, exhaust manifold and coolant expansion tank.

And if the car radiator does fail, it's not only much cheaper to replace, but also can't end up leaking sea water into your engine block, causing major follow-up damage.

Things I've learnt so far:

- Both Volvo and Perkins specify ethylene glycol antifreeze only (2 year cycle), no OAT (even in the latest publications, not just the original ones where OAT was possibly too new).
- Both recommend a 50/50 or 40/60 (Volvo, optional) antifreeze/water ratio (using soft water, distilled water or pre-mixed coolant)
- Both highlight the importance of using the correct corrosion inhibitors (but do not say what those are :nonchalance:)



I was hoping to find the Perkins stuff for less, but it doesn't seem to be available anymore, at least not where I've looked.
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My understanding is that the problem with cars in fact lies with the radiators . I believe that the old fashioned copper rads are not compatible with OAT antifreeze. Whether thast the copper itself or the solder used in the construction I dont know. Modern cars use aluminium radiators, which are compatible with OAT


You would be pretty hard pressed to find antifreeze that is not ethylene glycol based. All the common low silicate types and and the OAT types are ethylene glycol.
In the fullness of time the low toxicity propylene glycol based antifreeze will probably become more readily available. I have no idea if the inhibitors used in that available at present is low silicate or OAT

The yellow VP Coolant VCS is an OAT type and is specified for recent engines.
 
I think the issue with some modern antifreeze is that it attacks some plastics and gaskets?
The best thing is to avoid generalisations and use a known make of AF and go with the manufacturer's instructions.
There is some blurb on the Castrol and Morris's websites.
 
VicS said:
Any particular reason why you have chosen to use an OAT type when, AFAIK it is not specified. Like the colour? Believed it was "better"? Wanted a long life antifreeze to avoid changing every 2 years?
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Twas free from a mate who runs a garage.
 
nigelmercier said:
As this thread has been necrobumped, perhaps I could ask why it would need to be changed: for antifreeze properties, or anti-corrosion? Some of my friends were amazed that I was even able to buy the stuff!
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After 2 years the anti-corrosive additives (of the traditional type soup, not the OATy one) are supposedly depleted[1], and the coolant would also have picked up some contaminants. The antifreeze part can be measured via the specific gravity of the coolant, which is fancy words for you stick a cheap glass tube with a bobber in, suck up some coolant and read it off (very similar to battery acid testing). Then you can add more undiluted antifreeze or water depending on what it says. The Perkins manual suggests doing this once per year before it gets cold. The Volvo manual doesn't mention it.

Now during all this research I've accidentally stumbled upon a supplier of genuine Volvo Penta nectar for a price quite close to that of The Pink Stuff. Just put in an order, will see if it actually happens. This would cover both my need to save money and alleviate my fears of mistreating the heat exchanger into early retirement. I shall report back.

[1] http://www.coolantexperts.com/coolant_overview/traditional_coolant
 
nigelmercier said:
Thanks for the info. My engine had the same coolant in for at least 10 years, the traditional type, until I changed it. Should I be worried?
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If the coolant was still clear when you changed it, and the inside of the expansion tank was not coated in rust sediment, then it will be OK as the anti-corrosive additivies have kept corrosion at bay. If there was rust or sediment evident, then you have suffered some corrosion although I wouldn't recommend doing anything about it other than changing the coolant unless you have some other engine over-heating symptoms.

Richard
 
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