Is it bad on an engine to just run water instead of coolant in the radiator during the summer months? Especially a cat engine?
No it is definitely not good for a few reasons. You may notice that coolant feels a little oily, this is to provide lubrication to moving parts within the cooling system, mainly the waterpump. As water is circulated through the engine, were it comes into contact with the metal surfaces, tiny little implosions occur wearing parts. Coolant provides a barrier like protection to help reduce this effect. Also boiling point is reduced. Water can be used, but only in emergency situations. Until it can be refilled with coolant at a 50% concentration
I think it might be burning some coolant but I noticed it has a small leak in the radiator. Is there any kind of stuff "stop-leak" that I can buy and put in the radiator to stop or slow that leak down?
There are a few products available that will stop small hairline crack leaks, but again think they are for emergency repair only, is the machine overheating and your loosing coolant out the overflow bottle?
Not overheating or losing out overflow
Check out www.barsleaks.com.au these are the products we use in Australia.
Manufacturers used to have treatments for running straight water without antifreeze. Not recommended with newer engines because of more demanding cooling systems etc. I do it occasionally to flush a gunked up cooling system, but it's one of those things that's a little "on the edge". If you only have a leak in the radiator, I'd fix it by whatever means available before I'd drop in the tar balls.
I am by no means an expert but in the marine world people run distilled water with with an additive. Some marine diesels have marginal cooling systems and they will run signifigantly cooler with just water. I think just water has a lower boiling point than coolant. Double check me on that. I was running a boat that had temperature creep and took it in to the Detroit shop and they said I was overcharged (too much coolant). I thought it was BS but that was the problem. So too much coolant can lead too temperature creep and overheating. So I think you can run distilled water with an additive with no ill effects provided you are not worried about freezing temps.
Not recommended just to use water. Corrosion and cavitation caused by the heat right next to the liners will be your major issues. Glycol is just one of a dozen or so additives in coolant. The rest of them are all there for a purpose. Bars Leaks and similar compounds tend to plug up the inside of radiators and slow down coolant flow - thus adding to overheating problems, in my experience. Find the leak and have it fixed by a professional radiator repair shop would be my suggestion.
100% correct. Antifreeze boils at a higher temp so the cooling system can run hotter before it boils over. If you run straight water it will run cooler (water has a much higher heat capacity and lower viscosity than glycol) BUT the engine will boil over at a lower temperature. That assumes you have marginal coolant circulation, if the air flow through the radiator is plugged then water boiling lower will be BAD. I know some people run a little more than 50% antifreeze in colder climates for a little extra freeze protection. I wonder what they use in hot climates?
Standard premixed Extended Life Coolant is a 50/50 mix of coolant concentrate and water. It provides protection against freezing down to -35DegC which ought to be cold enough for most people. There is a premixed coolant that provides protection down to -50 DegC. IIRC it is a 67%/33% blend of coolant and water.
As Nige said, straight water causes a major cavitation problem, as it boils the water next to the liners even when the temp gauge is not showing an overheated condition. The heat is all created in the combustion chamber, and the temp spike there will boil the local water, but the flow will mix it with cooler water before it reaches the radiator or the gauge. Cavitation (tiny bubbles caused by boiling the water) when these bubles pop, it erodes the metal in the liners, and over time it will lead to holes all the way through into the cylinder.
If I can find some photos of cavitated liners I'll post them here. They will be enough to frighten you.....
Yes straight water is bad, but distilled water with an SCA additive will address the concerns of cavitation erosion and mineral buildup. CAT amongst others sells such a product. But maybe the OP is asking because he doesn't want to keep dumping expensive antifreeze into a leaking system. So by the time you buy the distilled water and the SCA additive you maybe right up there in cost with typical glycol antifreeze. If I knew how to post a link I would of the SCA additive that CAT sells. Also I have had two trucks that the manufacturers required an additive for cavitation corrosion in addition to the typical glycol antifreeze. My point is that some may read this and think that if they put glycol antifreeze in their engine they are automatically protecting their engine from cavitation erosion and I am not sure that is the case.
Here is a good read on cavitation. It is not geared toward cat engines but the same principals apply. http://www.oilburners.net/articles/cavitationartic.html
Out of interest, when did radiator coolant become common? Engines managed without it in the old days. Coolant is good, and I don't think it is a good idea to run with just plain water, but I also don't think it does much harm for short periods of time.
I wish I had some pictures of the wet liner engines like 855 Cummins we did many of over the years! Was not too bad that the liners got eaten away but when the block lower bores got involved that was really serious. We finally got the tooling to bore and sleeve the blocks lower bores. Then once we had the tooling upper management decided we were not qualified to do our own engine work so this expensive tooling just sits on a shelf unused. But at least cooling system maintenance has improved so have not seen a failed from cavitation liner in years.
According to wikipedia, permanent antifreeze, ethylene glycol, became available in 1926, but I'm guessing it became widely used after WWII. Before then alcohol was used in the winter and water in the summer. Or water in the winter and drained when the engine was shut off. The other link claimed SCA came into use in the 80's?? was it really that recently?
I'm going to divide my comments into two here: - 1. To the OP, who was asking about the feasibility of using plain water in the radiator in order to save on expensive antifreeze/coolant because of a coolant leak, the answer is no. I think the agreed consenus is to get the leak fixed correctly, fill the system with new coolant, and move on. 2. Now to the issue of coolant, antifreeze, and SCA ........ SCA (Supplemental Coolant Additive) has been around for years. I remember it in the mid-70s and I don't recall it being new technology even then. Its purpose was always to restore the properties of antifreeze when the additive package concentration had been depleted (who remembers the Coolant Test Kit?) to get it back up to scratch. SCA is effectively an additive package concentrate. SCA is designed for use with what some would call "old-fashioned" generally green-coloured antifreeze. This type of antifreeze will normally conform to ASTM Test Spec D6210. "Anti-freeze" is/was generally a concentrate that the user mixes with water to create the strength he wants in order to provide the necessary level of protection against freezing. The newer generation of coolants (note my change of wording here) are low-silicate. They still contain glycol as the anti-freezing agent but the additive package changes significantly. They are often referred to as Extended Life Coolant (ELC) because in machine applications they have a life of 12,000 hours provided the strength of the additive package remains up to spec. The concentrate for boosting ELC is often known as "ELC Extender" and works in exactly the same way as SCA in boosting the additive package of the coolant to get it back up to spec. Low-silicate coolants generally conform to ASTM Test Spec D4985 or D5345. Different to antifreeze, ELC usually comes premixed 50/50 with distilled water. This mixture will protect down to -35C. We were talking about cylinder liners. Here are a few photos of various engine parts. On the left, parts from engines that used poor-quality water + glycol + SCA as coolant. On the right engines using ELC. These were from the same customer after changing the coolant to ELC.
Sorry, forgot to post the photos ............... Oh, and by the way, the engine on the left had just over 5000 hours on it, the one on the right 10,300 hours.
Amazing what a little proper maintenance can do for the life of an engine I still recall going to work on a 3306 in a 966C, a few years back! I was doing an inframe overhaul at a location with a shed just big enough to get the little loader in and close the doors. I pictured finding liners much worse than those on the left in Nige's pictures with lower bore of block half gone by the top seal ring. Instead I was pleasantly surprised to find them as good or better than those on the right side Lower bore in block took a quick wipe with clean cloth to look like it just left the machine shop To say the least it made the job very enjoyable. I believe that was the time the boss at the location showed up with burgers and a beer, only one each, for the two of us doing the work when we were done. Would not want the safety germs to know about something like that these days
In my last job you could walk through the rebuild shop and immediately tell which customer an engine had come from by the condition of the parts without even having to look at the ticket on it. Simply put we knew who was using what coolant ............ those in the worst condition were always from a customer who used a recycled antifreeze as his coolant.
So if I add 50/50 antifreeze during the summer months I should be fine?
Yes you will be just fine as long as it has the proper sca ratings and such someone on here probably knows off the top of their head but find out what the manufacturer reccomends
I'm not sure I understand the question. Are you planning on fixing the leak first ..?
Done a pressure check and didn't lose any. I think I'm going to wait a while and then repair
In that case if you already have antifreeze in the cooling system, topping it off with a 50/50 mixture of antifreeze and distilled water would be fine. If you're at all unsure exactly what you have in there it would be more economical in the long run to drain the colling system, flush with water, and refill with the aforementioned mixture.
how about inland marine engines using lake water, how about the big boats ? the difference is that there is a never ending supply of cool water and I'm sure plays a major role in the equation though pj
Not an expert on marine applications but I always understood that instead of a radiator the engine would have a water/water cooler, with antifreeze circulating on the engine side and raw (salt or fresh) water coming in from the outside and sucking the heat away via the cooler. A bit like an engine oil cooler really but with water on both sides. Edit: Actually not. Just checked a 3516 Marine engine and they use a plate-type heat exchanger for the heat transfer between the raw water and the coolant. Specifiation is identical to a machine engine, ELC premix is the preferred coolant. One other gem came up as well. See below. I did not know this .......... "A Cat Diesel Engine equipped with air-to-air aftercooling (ATAAC) requires a minimum of 30 percent glycol in the coolant in order to help prevent water pump cavitation."
I am no expert either, but I know that most of the big engines have a heat exchanger as you describe, but some of the smaller engines don't. They just use raw water. I don't know what effect this has on their life expectancy. I had always thought of it as being like continuously flushing out a cooling system.
interesting pj
More like a continuous supply of fresh contaminants. You can "get away" with filling a system with hard water because the scale drops out and then the water is "clean", but if you keep adding the same water then the radiator will plug up sooner or later. I have zero experience with raw water cooling, but lots of experience with plugged radiators, and water heaters full of scale.
Even in a heating unit in a commercial building that uses a water exchanger as with a gas fired boiler, will add something in the water to keep it from corroding the pipes and radiators. Distilled water can be expensive when you use a lot. I have two dehumidfiers in our basement at home I put the drain hoses in 5 gal buckets and when full take it to the shop and fill a 30 gal plastic barrel. This way I have water free of any iron, etc.
What a great idea! I keep pouring it down the drain! Anyone else have any thoughts about dehumidifier water in cooling systems?
On the boats I worked, with CATs and Detroits the cooling systems were "keel cooled" with an expansion tank. Along with the coolant mix, these engines had lots of pipe plugs in the cooling system that had small zincs threaded into the end, one more thing on the checklist whenever we changed oil and filters.
Back in the 2 cycle days, Detroit diesel used to have a guideline for extra coolant additive to be run with straight water. I don't remember if it was actually acceptable by them, or if they just grudgingly allowed it because they knew people were going to do it.