coolant to water ratio for 5.9 cummins

[ruSSrt]

Hello everybody!

I'm getting ready to change coolant on my 01 cummins. Its about 30k on the current and i try to change it about every 30k miles with cheap green coolant. All my previous coolant changes I purchased 50/50 pre diluted coolant and just poured it in until it was full. A while back I read on this forum about coolant ratio and that it was okay to have 60-70% coolant and 40-30% water. Would it be better to keep engine cooler in hot summer months here in SC?
Also I started towing a dump trailer and use it on the property and realized that my truck is getting hotter when I tow. Thats why I got 190 degree thermostat to change out and hoping to get "better cooling" with high ration of coolant?
I'm thinking about flushing coolant system by following moparman write up and flushing it with water to make sure to get old coolant out of heater core and everywhere. And then start filling it up with coolant concentrate. Its about 3 gallons of coolant, so i would use 2 gallons of concentrate and then fill the rest with water.
Anyone see of any issues with that?

 

[Jimmy_Russells]

More coolant percentage will not significantly change the operating temperature of the engine. It just allows the coolant mixture to get colder before freezing.

 

[tnt_motorsports]

I've always shot for a 50/50 mix when changing coolant.

Just my $0.02

 

[Davejam]

I think you have it backwards. More water will keep it cooler. Water is a more effective heat transfer medium.
For Cummins I wouldn't go below 60% water/40% Coolant.

Its not clear which coolant you intend to use, i'd be very sure to use the correct coolant for the application.

 

[AdmiralYoda]

Use whatever the manufacturer recommends, which is probably 50/50. Adding more coolant than water decreases the freeze temp but does not help cooling.

If you are running hot find the problem. Electric fan? Mechanical fan clutch? Water pump fins worn out? Plugged radiator?

 

[ruSSrt]

I guess all this time I understood it incorrectly. I though coolant was the one providing better heat transfer, and not water.

 

[ruSSrt]

More coolant percentage will not significantly change the operating temperature of the engine. It just allows the coolant mixture to get colder before freezing.

I didnt think it'll change operating temperatures of the engine. I wanted a quicker heat transfer from engine to fluid, and then back from fluid to radiator/air. IN turn keeping engine cooler.

 

[tnt_motorsports]

I didnt think it'll change operating temperatures of the engine. I wanted a quicker heat transfer from engine to fluid, and then back from fluid to radiator/air. IN turn keeping engine cooler.

The thermostat is what controls the cooling temperature of your system until it becomes saturated with heat then the heat transfer of the fluid and cooling system comes in to play. I’d stick to a 50/50 mix and ensure your system is up to snuff if you have issues.

Just my $0.02

 

[Davejam]

The thermostat set temperature is basically your lowest operating temperature.
Low-medium loads likely operates within 10-15 degrees of that min and are totally fine. Think temperatures High loads including towing will tax the system beyond that and where heat transfer of the coolant/water mix could make some difference.
But if you're not seeing high temperatures this isn't really necessary. I would think a medium load on a Cummins engine is a fairly hefty as they are designed to pull many tons.

Here is a very good reference.

Ethylene Glycol Heat-Transfer Fluid Properties

Properties like freezing point, viscosity, specific gravity and specific heat of ethylene glycol based heat-transfer fluids, or brines.

www.engineeringtoolbox.com

Generally you would want to choose coolant based on freeze protection. In my case in FL i've never seen temperatures SC is more varied, so you have to apply similar logic for your climate, but I would think 40% coolant is still relatively safe.

The other point to mention is that coolant has other additives for rust protection, cavitation protection, etc that is guaranteed for a certain number of miles based on 50/50 concentration. So, that's another reason not to venture that far from that midpoint.

 

[Number_35]

I didnt think it'll change operating temperatures of the engine. I wanted a quicker heat transfer from engine to fluid, and then back from fluid to radiator/air. IN turn keeping engine cooler.

Some people add a "water-wetter" which I believe is a surfactant, reducing the surface tension of the water and thereby improving heat transfer.

 

[kschachn]

Some people add a "water-wetter" which I believe is a surfactant, reducing the surface tension of the water and thereby improving heat transfer.

Which is already present in a formulated coolant, "water wetter" helps with straight water in a track car.

 

[Davejam]

Which is already present in a formulated coolant, "water wetter" helps with straight water in a track car.

Exactly. Do not use additives in fully formulated coolant unless you are certain that it is A) useful and B) compatible.
I wouldn't recommend it here.

 

[Number_35]

About 20 years ago one of my coworkers had persistent overheating with his Jeep Cherokee.

The problem turned out to be that he had way too high a concentration of antifreeze.

 

[SureshR]

Entirely depends on the coolant concentrate. I’ve seen some in the market that are a 1:8 or 1:9 dilution.

 

[kschachn]

Entirely depends on the coolant concentrate. I’ve seen some in the market that are a 1:8 or 1:9 dilution.

That’s a new one. The owners manual specifies this concentration?

That sort of concentration with an ethylene or propylene glycol coolant would be insufficient. In fact, I’m not sure what kind of a solute would give adequate freeze and boil-over protection, not to mention corrosion protection.

 

[Snagglefoot]

I think you have it backwards. More water will keep it cooler. Water is a more effective heat transfer medium.
For Cummins I wouldn't go below 60% water/40% Coolant.

Its not clear which coolant you intend to use, i'd be very sure to use the correct coolant for the application.

60 /40 won’t cut it in Edmonton.

 

[SureshR]

That’s a new one. The owners manual specifies this concentration?

That sort of concentration with an ethylene or propylene glycol coolant would be insufficient. In fact, I’m not sure what kind of a solute would give adequate freeze and boil-over protection, not to mention corrosion protection.

These are “super concentrated”, so 1:7 would give you what is effectively a 50-50 mix of coolant and water. Here are a couple of generic OAT examples available in India

 

[kschachn]

These are “super concentrated”, so 1:7 would give you what is effectively a 50-50 mix of coolant and water. Here are a couple of generic OAT examples available in India

Right, in India. You can’t be “super concentrated” beyond 100% ethylene or propylene glycol. 1:7 cannot be 50% no matter how you slice it. At that concentration, you are providing minimal corrosion resistance and a bit of boiling point elevation.

The other thing is that below 50% it doesn’t matter what the solute is. Freezing point depression and boiling point elevation is independent of the solute on a molal basis. 1:7 cannot be equal to 50%. In terms of additives and corrosion protection it may be adequate. But you can’t change physics in terms of boiling point and freeze protection.

 

[SureshR]

Right, in India. You can’t be “super concentrated” beyond 100% ethylene or propylene glycol. 1:7 cannot be 50% no matter how you slice it. At that concentration, you are providing minimal corrosion resistance and a bit of boiling point elevation.

The other thing is that below 50% it doesn’t matter what the solute is. Freezing point depression and boiling point elevation is independent of the solute on a molal basis. 1:7 cannot be equal to 50%. In terms of additives and corrosion protection it may be adequate. But you can’t change physics in terms of boiling point and freeze protection.

Additive chemistry would be my guess to make up for this excessive dilution. Like you say the physics don't add up here.

 

[dumkid]

Right, in India. You can’t be “super concentrated” beyond 100% ethylene or propylene glycol. 1:7 cannot be 50% no matter how you slice it. At that concentration, you are providing minimal corrosion resistance and a bit of boiling point elevation.

The other thing is that below 50% it doesn’t matter what the solute is. Freezing point depression and boiling point elevation is independent of the solute on a molal basis. 1:7 cannot be equal to 50%. In terms of additives and corrosion protection it may be adequate. But you can’t change physics in terms of boiling point and freeze protection.

coolant concentrate still has a little bit of water in it. if you took the water out of concentrate i guess you could run a 40% ish coolant to water ratio instead of 50% and have the same amount of glycol in the system.