Which antifreeze for a Yanmar 3YM

Tim Good

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I was under the general impression that antifreeze type / brand is not that critical providing it contain reasonable corrosion inhibitors. Mine is the red stuff that apparently lasts longer but I don't think the colour had an industry standard. I got it from the local motor shop and contains a gycol type inhibitor.

Oil on the other hand I do stick to the book and buy decent stuff.
 

jwilson

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When the 3YM30 first came out a lot of the early engines overheated if run at highish revs - often recently commissioned engines in brand new boats (mostly Hunters and Jeanneaus). People in warm water Florida etc found this first, and it happened at lower revs than mine. Initially it was blamed on "wrong antifreeze" causing some sort of furring/gunging up of the heat exchanger.

After multiple complaints about this Yanmar started fitting better heat exchanger inner pipe sets with more tubes, and changing this under warranty for those who complained. They did NOT though issue a recall. The first 5,000 or so engines sold in 2004/5 were thus definitely undercooled - mine was one of those.

The official line is to use ONLY Texaco Long Life Coolant or Havoline Extended Life Antifreeze/Coolant, which I believe are yellowish, though my Jeanneau with a 3YM30 came with blue antifreeze from new commissioning, and it has always been replaced like for like by my local Yanmar agent, whom I trust. Another Yanmar agent has however told me that the intermittent overheating issues I have had since (even after the improved heat exchanger core was fitted) would be the result of using non-yellow "official" antifreeze.

If I motor at very near or at full revs for 10 mins plus (as I make a point of doing every now and then) I can still occasionally get the overheat alarm to come on. Throttling back shuts the alarm off after a short time. Checks with a laser temp gauge have shown that on these occasions the engine is actually starting to overheat - it's not just a temp sensor fault. It does not always happen though.

http://www.ybw.com/forums/showthread.php?313942-Yanmar-3YM30-overheating gives some more info - three years on it weirdly seems to be happening less often: the only thing changed has been new under-hull bronze inlet fittings to replace the Jeanneau brass ones. It does still occur occasionally, almost at random, but only at high revs.
 

lw395

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I would investigate the overheating in terms of:
a) is the overheat alarm actually meaningful, what is the water temp in the head?
b) what is the temperature of the water leaving the heat exchanger? Is there too little seawater flow, or is the heat not getting to the seawater side?
c) Is the engine generating more heat than it should? Could be timing, either valves or injection?
d) Is the freshwater/coolant flow inadequate, or not going where it should? Can you spin the pump faster, or maybe use an electric circulator.
e) Is the calorifier installed right/is it influencing the flow somehow?
Other things to try include thermostats which might be less restrictive. I am assuming the thermostat is fully open before the alarm goes off?
In my view, motoring at max rpm in flat water may not be worst case. What's it going to do if you need to bash into wind and waves and really work it hard?

After how short a time does the alarm go off when you reduce revs?
Would you not expect the coolant temp to keep rising for some minutes as heat flows out of the head into the coolant, but the seawater flow has much reduced with the RPM, if the heat exchanger is limiting the cooling?
 

VicS

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It's pinkish, rather than pay Yanmar exorbitant prices can I use any commercial red antifreeze?

A long life antifreeze is specified ( Texaco and Havoline one ones being specifically named in the operating manual)

If you cannot obtain, or do not wish to pay for, the Havoline orTexaco be sure to use a long life or "Organic Acid Technology" (OAT) type of antifreeze.

There is no standardisation of colours. Read the writing on the label ........... thats what counts, not what pretty colour it is.

Operating manual : https://j109.org/docs/yanmar_ym_series_operations_manual_v2_21jan09.pdf


Note that the antifreeze should not be diluted with hard water. Unless you know your water supply to be soft/ low in total dissolved solids use distilled water for dilution .... or buy it ready diluted

Concentrate:
http://www.halfords.com/motoring-tr.../halfords-oat-antifreeze-concentrate-2-litres
http://www.halfords.com/motoring-tr.../halfords-oat-antifreeze-concentrate-5-litres

Ready diluted:
http://www.halfords.com/motoring-tr.../halfords-oat-ready-mixed-antifreeze-5-litres
http://www.halfords.com/motoring-tr.../halfords-oat-ready-mixed-antifreeze-2-litres
 
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jwilson

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I would investigate the overheating in terms of:
a) is the overheat alarm actually meaningful, what is the water temp in the head?
b) what is the temperature of the water leaving the heat exchanger? Is there too little seawater flow, or is the heat not getting to the seawater side?
c) Is the engine generating more heat than it should? Could be timing, either valves or injection?
d) Is the freshwater/coolant flow inadequate, or not going where it should? Can you spin the pump faster, or maybe use an electric circulator.
e) Is the calorifier installed right/is it influencing the flow somehow?
Other things to try include thermostats which might be less restrictive. I am assuming the thermostat is fully open before the alarm goes off?
In my view, motoring at max rpm in flat water may not be worst case. What's it going to do if you need to bash into wind and waves and really work it hard?

After how short a time does the alarm go off when you reduce revs?
Would you not expect the coolant temp to keep rising for some minutes as heat flows out of the head into the coolant, but the seawater flow has much reduced with the RPM, if the heat exchanger is limiting the cooling?

I'm not an diesel engineer, but two who are have watched this engine overheat and they agree it does.

Bags of water flows through and out the exhaust even at tickover, in fact the water flow does not seem that much different at tickover and high revs. Alarm goes off usually within 20 seconds of throttling back from 3000+ to 1200-1500-ish

As this has persisted through a new heat exchanger core, new water pump, new exhaust elbow and running with thermostat removed, I still think Yanmar put in fractionally too small a heat exchanger in the 3YM30. Interestingly I have never heard of the same overheating problem on a 3YM20, which is a derated version of the same 3-cylinder engine, whilst lots of 3YM30 owners have had similar problems.

In practice I regard cruising revs as 2600-2800 which gives about 7 knots on a clean hull, about 6.5 by the end of the season, and it does not usually overheat at these revs. 3000 is often OK too, 3200-3400 will quite often (but not always) cause overheating. Apart from this the engine runs beautifully, and even at fairly high engine hours (boat is chartered) starts instantly, no smoke at any revs or power. Charterers rarely seem to run the engine hard - the ones I have met seem horrified that I regard as high as 2800 rpm as "cruising" but if I'm running an engine it's to get somewhere, and I believe in diesels getting a bit of hard work.

In this particular boat the limiting factor in "bashing into wind and waves" is keeping your teeth intact from the hull slamming, so you rarely use fullish power.
 

RichardS

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It's pinkish, rather than pay Yanmar exorbitant prices can I use any commercial red antifreeze?

The Halfords Long Life OAT I use in the boat is the pinkish stuff. The Ford Longlife OAT I use in Ford is clear whilst the Jaguar OAT I used to use in the Jag was yellow although I changed to the Ford stuff a few years ago.

As Vic says, the colour is meaningless.

The type/colour of antifreeze will have no effect on the cooling system. Varying the concentration of antifreeze from 0% to 50%, would in theory, affect the cooling efficiency but I doubt that any engine will be designed with such a limited overheating tolerance that it would make any observeable difference.

Richard
 

Aurai

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Engine manufacturers

May be getting around patents for anti/freeze by branding their own and use colour to further distance themselves from patented product!

It must be the mix we look to match as per guidance above.

?
 

lw395

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I'm not an diesel engineer, but two who are have watched this engine overheat and they agree it does.

Bags of water flows through and out the exhaust even at tickover, in fact the water flow does not seem that much different at tickover and high revs. Alarm goes off usually within 20 seconds of throttling back from 3000+ to 1200-1500-ish

As this has persisted through a new heat exchanger core, new water pump, new exhaust elbow and running with thermostat removed, I still think Yanmar put in fractionally too small a heat exchanger in the 3YM30. Interestingly I have never heard of the same overheating problem on a 3YM20, which is a derated version of the same 3-cylinder engine, whilst lots of 3YM30 owners have had similar problems.

In practice I regard cruising revs as 2600-2800 which gives about 7 knots on a clean hull, about 6.5 by the end of the season, and it does not usually overheat at these revs. 3000 is often OK too, 3200-3400 will quite often (but not always) cause overheating. Apart from this the engine runs beautifully, and even at fairly high engine hours (boat is chartered) starts instantly, no smoke at any revs or power. Charterers rarely seem to run the engine hard - the ones I have met seem horrified that I regard as high as 2800 rpm as "cruising" but if I'm running an engine it's to get somewhere, and I believe in diesels getting a bit of hard work.

In this particular boat the limiting factor in "bashing into wind and waves" is keeping your teeth intact from the hull slamming, so you rarely use fullish power.
Interesting.
I'm not a diesel engineer either BTW.
The only course of investigation I can suggest is whether the heat is actually getting to the heat exchanger.
Could it be the circulating pump does not work as well at high RPM?
Vibration affecting water flow?
Some sort of airlock that moves around the engine?

Just because the engine is doing 3400rpm, does not necessarily mean it is putting out the most heat, if the load is light.
I would expect the heat exchanger to be able to lose the maximum waste heat the motor can put out.
What happens if you load the motor at lower revs, e.g. by towing another boat or motoring while moored?

20 seconds seems quite a short time for normal cooling to resume, but from what you say the system is not limited by seawater flow.
(As a comparison, my motor bike tends to show increasing temperature for some minutes after slowing, I assume the metal of parts of the head must get much hotter than the water, and this heat takes a while to come out).

AIUI, too high a concentration of anti-freeze will reduce the heat capacity of the coolant, which may reduce cooling capacity.
There are other additives you can put in coolant to (allegedly) increase heat removal, sometimes used in rally engines, I am not sure whether or how they work, because I've never needed to find out.

Is there an oil cooler or gearbox cooler in the system?
It might be interesting to measure oil temp as well as water temp.
 

tony_lavelle

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I have a similar problem with the Volvo MD2030 on my Westerly Corsair. Overheats when doing 3000+ rpm for 10 minutes but alarm goes off after a minute if revs reduced. I have been told that my propeller may be oversized or too large in pitch, so the engine is having to work too hard.
 

VicS

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Beware, though, that using OAT antifreeze in a system designed for glycol, like older cars, can do horrible and expensive things to various components.

OAT antifreeze is, just like conventional low silicate antifreeze, glycol based
 

Tranona

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I have a similar problem with the Volvo MD2030 on my Westerly Corsair. Overheats when doing 3000+ rpm for 10 minutes but alarm goes off after a minute if revs reduced. I have been told that my propeller may be oversized or too large in pitch, so the engine is having to work too hard.

Is 3000 the maximum you can get? If so it is overpropped. Recommendation is at least 3400, so you need to reduce pitch at least an inch, possibly 2.
 

CJU

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I'm not an diesel engineer, but two who are have watched this engine overheat and they agree it does.

Bags of water flows through and out the exhaust even at tickover, in fact the water flow does not seem that much different at tickover and high revs. Alarm goes off usually within 20 seconds of throttling back from 3000+ to 1200-1500-ish

As this has persisted through a new heat exchanger core, new water pump, new exhaust elbow and running with thermostat removed, I still think Yanmar put in fractionally too small a heat exchanger in the 3YM30. Interestingly I have never heard of the same overheating problem on a 3YM20, which is a derated version of the same 3-cylinder engine, whilst lots of 3YM30 owners have had similar problems.

In practice I regard cruising revs as 2600-2800 which gives about 7 knots on a clean hull, about 6.5 by the end of the season, and it does not usually overheat at these revs. 3000 is often OK too, 3200-3400 will quite often (but not always) cause overheating. Apart from this the engine runs beautifully, and even at fairly high engine hours (boat is chartered) starts instantly, no smoke at any revs or power. Charterers rarely seem to run the engine hard - the ones I have met seem horrified that I regard as high as 2800 rpm as "cruising" but if I'm running an engine it's to get somewhere, and I believe in diesels getting a bit of hard work.

In this particular boat the limiting factor in "bashing into wind and waves" is keeping your teeth intact from the hull slamming, so you rarely use fullish power.


My 3YM used to overheat if revved to over 2,500 for more than 15 mins. Checked all the usual things first but eventually removed the tube stack from the heat exchanger and found the tubes were coated in a jelly like substance. I cleaned this off, put them back, flushed the system through and it has been OK for the last 6 years. A Yanmar agent said this was probably dew to the previous owner using the wrong coolant, so now I only use the Yanmar pink coolant
 

FullCircle

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Ok, Yanmar 3YM30 coolant is,(as said before) Texaco/Havoline. It's hard to get hold of.

The Orange coolant is supplied to all General Motors vehicles by Texaco Havoline from 2003 onward. Therefore any GM dealership, Vauxhall orChevrolet will supply the stuff at around £4 a litre, labelled with GM packaging.
 
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