locomotive coolant systems.

[G Mack]

Hello everyone,

I have always heard that locomotives don't use anti-freeze in the coolant system and was wondering why. Is it something about diesels that are incompatible with anti-freeze or is it an economic consideration? I did do a search of past threads on the forum but didn't find anything that directly answered the question. Do any of the newer locomotives use an anti-freeze in the coolant? 

Thanks for any info,

Gregory

[J. Edgar]

they use plain old tap water.......mostly enviromental issues....but when you need 300 400 gallons at some wayside point......waters better then anti-freeze.......also in colder climates when they get shut down or break down they can just be drained on the ground

[CSSHEGEWISCH]

Another factor that makes a difference is the leak factor.  Locomotive cooling systems are not as watertight as that of your average Dodge Magnum, and ethylene glycol causes deterioration of lube oil if it leaks into the crankcase.

Also consider the cost of a 50-50 glycol-water mix for a cooling system with a 300-gallon capacity.

[dldance]

Are diesel coolant systems pressurized?

dd

[G Mack]

Are diesel coolant systems pressurized?

dd

I remember reading in one of the threads on this subject that the coolant system is not pressurized. Another good question though. Maybe one of our forum members knows more.

Gregory

[G Mack]

Thanks for the responses.

So it seems that it is a compilation of several factors. The cost of buying and stocking a lot of anti-freeze, the environmental dangers, and the risk of ruining a prime mover if the coolant leaks into the interior.

Years ago, I worked on offshore drilling rigs and I don't remember them using anti-freeze in the diesels out there either.

Gregory

[WSOR 3801]

They have a pressure cap, like an automobile, just bigger.  Some of our engines have water pump lube in them, turns the water green.  Easier to see in the sight glass. 

The main reason for using regular water instead of antifreeze is the bearings get wiped out by antifreeze.  An EMD is not watertight, and some water in the oil can be dealt with.  Water doesn't hurt the bearings like antifreeze does.  Some EMDs do use antifreeze, but you would have to keep close tabs in them to guard against contaimination.  Normal mainline power would not have antifreeze. 

[Anonymous]

yes they are pressurized but not as much as your standard car, which is usually around 15psi.  As for the newer emd's I know the sd90mac's came with antifreeze and some of the ac6000's did as well.  I don't know if the sd70ace's or es44's are running antifreeze.

[oltmannd]

Early EMDs (e.g. GP9s) were not pressurized, but newer ones are.  All use raw water with a corrosion inhibitor added.

Three problems with antifreeze:

1. antifreeze + lube oil = goo.  A water leak into a hot crankcase will vaporize the water on contact with the oil.  But, antifreeze will just mix with the oil - and the mixture doesn't lubricate well.  It's not uncommon for EMDs to have water leaks into the crankcase.

2. Surprisingly, and antifreeze/water mixture doesn't have the cooling capacity of raw water.  Not such a big deal in the east, but could be a big deal in the Southwest.

3. Antifreeze (ethylene glycol) is toxic.  RRs don't want to mess with nasty stuff any more than they have to.  You could use non-toxic propylene glycol, though.

[carnej1]

 EMD developed their 265-H engine(used in the SD90MAC-H) as antifreeze compatible. The GE HDL(AC6000CW) is as well. I'm not sure about the GEVO engine (based on the HDL)......

[Mimbrogno]

Locomotives do have pressure fed coolent systems, but they are not the closed circut type as found on a car. Most locomotives have an expansion tank to hold the extra volumn of heated water, and they also have an overflow drain that vents any pressure that may build up, as well as excess water, outside to the ground. This is one reason why locomotives do not have antifreeze in them, as when they run the are regularly topped off with water, with the excess water being dripped off all the way down the line. Another reason is that it makes the water much thinner, and will exasperate any leaks that the coolent system already has, which would probably make it leak four times as much as if it did have antifreeze.

Locomotives do not run with untreated water though. A chromate compound is needed every time the coolent system is flushed and refilled. It acts as a rust inhibitor and also protects the delicate radiators from contaminents in the water. If the chromate compound is not used, the metal would rust the moment the water is drained from the system.

Matthew Imbrogno
-Mechanical Volenteer, Arizona Railway Museum
www.azrymuseum.org

[curtisporky]

I do remember seeing old Rock Island U25B's (and other RI U-boats) with a yellow substance that had blown out of one of the long hood doors, and was told years ago that it was "coolant". Any ideas on what it may have been, if not anti-freeze?

Porky Curtis-Keeping the memory of the Rock Island alive.

[beaulieu]

I do remember seeing old Rock Island U25B's (and other RI U-boats) with a yellow substance that had blown out of one of the long hood doors, and was told years ago that it was "coolant". Any ideas on what it may have been, if not anti-freeze?

Porky Curtis-Keeping the memory of the Rock Island alive.

That would be the Chromate compound used as a rust inhibitor.