Antifreeze Mix Ratio for Ford Lehman 120

[GrandBanks42]

Hello All,

I'm new to this forum and not exactly sure how it works so here it goes...

I have a Grand Banks 42 with twin Ford Lehman 120's. I am servicing the coolant system and know I'm supposed to use Ethylene Glycol but can't find any real info on if I should, should not or doesn't really matter to mix the coolant with distilled water. Can someone help me answer that question?

 

[DavidM]

Every engine I have known used a 50/50 mix of antifreeze. That ratio gives you the highest boiling point.

David

 

[GrandBanks42]

Thank You David

 

[High Wire]

And you don't really need distilled water when you are pouring it into an old cast iron block. Clean tap/drinking water is ok.
Save the distilled for batteries.

 

[Ski in NC]

If not subjected to really harsh freezing temps, I fill engines with about 33% glycol. I do use distilled water as it is a buck a gallon at the grocery and dockside water in my area can be really skunk well water, or from a water softener that releases a trace of salt.

Can't go wrong at 50/50 though.

 

[FF]

"I fill engines with about 33% glycol."

In non heavy freezing areas this is a great idea.

1/3 antifreeze gives the required freezing / corrosion protection and water pump lubrication , and since antifreeze is only 3/5 as good a heat conductor as plain water gives better overheat protection than 50/50.


On a new engine with a 15psi pressure cap 50/50 will give a higher boiling point , but on an antique with a 2 or 3 psi cap 1/3 antifreeze ,+ distilled water and getting ALL the air out of the system is better.

 

[Comodave]

I go 50/50 with distilled water.

 

[Civilitas]

I do use distilled water as it is a buck a gallon at the grocery and dockside water in my area can be really skunk well water, or from a water softener that releases a trace of salt.

Strongly agree w/this. For a $1/gallon, there's no reason not to do so.

Unless you are REALLY sure what's in your tap water, this is cheap insurance.

 

[SoWhat]

Prestone 50/50 premix. $8.88/gal at Walmart.

 

[Civilitas]

Prestone 50/50 premix. $8.88/gal at Walmart.

I would definitely not use that in an older engine. Reputable sources say the Prestone AMAM has 2-eha in it, which slows eats some types of gaskets. I am told that is a Dexcool clone.

 

[SoWhat]

I would definitely not use that in an older engine. Reputable sources say the Prestone AMAM has 2-eha in it, which slows eats some types of gaskets. I am told that is a Dexcool clone.

Old rumors perpetuated by the internet. It was claimed many years ago that 2-EHA attacked plastic contained in intake manifold gaskets. Prestone MSDS states it has a small percentage of 2-EHA. All the gaskets in my 35 year old Lehman engines are just fine.

Prestone is dyed green. Dex-cool is dyed red. They are both based upon Ethylene Glycol so yes, they're basically clones.

 

[psneeld]

American Diesel said cheapo green glycol from anywhere is just fine.


My 120 Lehman seems to be fine with it.

 

[Civilitas]

Old rumors perpetuated by the internet. It was claimed many years ago that 2-EHA attacked plastic contained in intake manifold gaskets. Prestone MSDS states it has a small percentage of 2-EHA. All the gaskets in my 35 year old Lehman engines are just fine.

What? a Myth - it certainly isn't. GM and Ford would wish it was, as then they wouldn't have had to honor warranties and received such a black eye for the damaged gaskets. This isn't some "internet myth." it certainly didn't impact all engines, but it does exist.

The 2-eha acts as a "plasticizer" on some gasket material (it does not attack plastic). Engineers discovered this in the late 90s and modern gaskets and engines SHOULD be safe. Not all gasket material is affected and the head gaskets in a Ford Lehman may certainly be safe. But are allgaskets in all old engines, and heat exchangers safe? Maybe some heat exchanger gaskets are safe, maybe some replacements are not. No one can say for sure. IMO it's not worth saving a few dollars using a dex-clone in an older engine not "Death-cool" proofed.

It's worth knowing the risk. People can choose to take it, but it's not worth ignoring.

American Diesel said cheapo green glycol from anywhere is just fine.


My 120 Lehman seems to be fine with it.

Yep, that would be my choice. No risk. Not as cheap or easy to find as dex-cool/AMAM type coolant these days, but not hard.

 

[psneeld]

I use the premix 50/50 or concentrate Prestone from Walmart.


Not sure what the AMAM designation is...but when I Google it, it comes up with the cheapo green stuff...not the Prestone DexCool pre mix which is in a grey container, not yellow.

 

[SoWhat]

What? a Myth - it certainly isn't. GM and Ford would wish it was, as then they wouldn't have had to honor warranties and received such a black eye for the damaged gaskets. This isn't some "internet myth." it certainly didn't impact all engines, but it does exist.

It is an internet myth, perpetuated by a couple of well known internet writers 20 years ago. The so-called 2-EHA 'plasticizer' gasket problem has never been documented by any scientist in any peer reviewed chemical or metallurgical journal. Nor has any auto manufacturer ever published anything about 'plasticizer' gasket problems. They do specify recommended anti-freeze types, engine oil types, brake fluids, etc.

Please provide links to accurate information from engineering journals and not links to self annointed flat earth experts like joe the oil guy.

 

[GrandBanks42]

Thank you all for your help here and sorry for the much delayed response. Being new to this it took me awhile to figure out how to get back to the thread.

 

[SteveK]

50/50 is the recommended. But unless you drain it bone dry and start over?
50/50 mix on the hydrometer should show as -34 & 285

 

[RT Firefly]

Greetings,
Mr. GB42. Welcome aboard. I'm pretty sure whatever anti-freeze you use HAS to be specifically for diesel engines.

 

[catalinajack]

Why? The coolant is in a closed system. Type of engine doesn't matter.

Greetings,
Mr. GB42. Welcome aboard. I'm pretty sure whatever anti-freeze you use HAS to be specifically for diesel engines.

 

[Nomad Willy]

I use the green stuff about 33%. The other colors are for cooling systems where aluminum comes in contact w the AF coolant.
No need for even that much cold protection.

As to 50/50 how on earth is your boat engine going to get down to -34f ? Mine never getts to freezing so water would be just fine.
But want a higher boiling point so I use 33% AF mostly for that. My cooling system runs at 200 maybe 205 degrees.

 

[psneeld]

Depends on the engine and what kind of and how much silicates (?) are in the coolant to prevent cavitation erosion.


Lehmans aren't susceptible to it I guess.

 

[Ski in NC]

Cast iron cylinders like the Ford, Cummins 5.9, Cat 3208, 3116, etc are not susceptible to cavitation damage. Steel replaceable liners are susceptible, and you have to be careful with coolant chemistry. Especially engines that run hard where cavitation can occur. Cast in liners like the Ford, you want good coolant but you don't have to be super picky.

 

[Comodave]

I asked Brian at AD. He said any good antifreeze is fine.

 

[AusCan]

Be careful what type of antifreeze you are adding.

There are 3 main types of ethylene glycol antifreeze:

TYPE INHIBITOR TECHNOLOGY
IAT (Inorganic Additive Technology) Silicates
OAT (Organic Acid Technology) Organic Acids
HOAT (Hybrid OAT) Silicates & Organic Acids
HOAT (Hybrid OAT, Phosphate-free) NAP Free

Do not ever mix IAT and OAT antifreeze. It will turn into a gel and cause overheating.

All types come in a variety of colours but IAT is usually green. OAT is usually orange, but don't count on it. Read the fine print.

 

[Aquabelle]

Every engine I have known used a 50/50 mix of antifreeze. That ratio gives you the highest boiling point.

David

Surely that's not right? 50:50 MAY give higher anti-corrosion properties but 30:70, recommended by more than a few brands, will give a higher boiling point I think.

 

[syjos]

Diesels can use any anti freeze. Low silicate is preferred.

Anti freeze provide othe benefits besides cooling. It lubricates pumps and prevents corrosion.

 

[psneeld]

Surely that's not right? 50:50 MAY give higher anti-corrosion properties but 30:70, recommended by more than a few brands, will give a higher boiling point I think.

https://www.hella.com/techworld/us/Technical/Car-cooling-system/Refilling-coolant-2708/



mixing ratio of water andantifreeze

should be from 60:40 to 50:50. This usually corresponds to​

antifreeze

protection at temperatures of –25°C to –40°C. The minimum ​

mixing

ratio should be 70:30 and the maximum 40:60. Increasing the proportion of​

antifreeze

(e.g. 30:70) does not lower the freezing point any further.

​

 

[Nomad Willy]

When I rode a BMW I read that 60-40 was best. That may have been biased toward the boiling point. May be optimized as in if you add any more there’s little or no benefit .. re the boiling point.
I suspect many sources say 50/50 because it’s easy to remember. You can imagine somebody wondering “is it 40-60 or 60-40.

But all this is approximate as I have yet to see any scientific laboratory beakers being used.

 

[Ski in NC]

A few engr notes regarding AF:

1. Why mix for lowest freeze point. How many trawler engines are exposed to -50F?
2. Water may freeze at 32F and boil at 212F, but between those extremes it actually has better heat transfer: Higher specific heat, higher thermal conductivity and lower viscosity.
3. If freezing is not an issue, you can go with distilled water and commercially available corrosion inhibitor package. Gets you the same protection as AF regarding corrosion. So if you don't need freeze protection, why mess with that slimy stinky stuff?

I have solved a bunch of overheats on southern boats where I knew the heat exchangers were designed with very little heat transfer margin. Got rid of the 50/50 and went with water and corrosion inhibitor. It worked.

On boats I service, and my personal boat in NC, I run 33% glycol. Except Yanmars and anything else with lots of aluminum, those I follow the book. Don't need the liability if the Al rots.

 

[syjos]

In automotive motorsports, water based antifreeze is seldom used. Due to the high temperatures that auto engines experience on the race track, waterless coolants have been developed to mitigate heat more effectively.

I use Evan's Waterless Coolant in my track car engine.

I don't think boat engines experience overheating issues unless in tropical water or the heat exchanger become blocked We just don't run our trawler engines hard enough and the seawater cooled heat exchangers are more efficient at dissipating heat than an air cooled auto radiator.