Water pumps

I just read the post about straight water in the radiator vs a water and antifreeze mix. Several posts made comments about the antifreeze lubricating the water pump, and I just wanted to set something straight about that.

Having worked on water pumps on engines, as well as industrial water pumps of varying designs, I have found that most of them use basically the same mechanical type seal. That being the case, the faces of the seal are mirror polished, and ride together under spring tension. Riding together like they do, they are leak free, thus no water/coolant gets between the seal faces. In other words a mechanical seal, by design, needs no lubrication, only the cooling effect of the liquid being pumped.

That being the case, the seals in a water pump, wether it's on a vehicle engine, or a 12 inch, engine driven pump dewatering a quarry, don't care whether the liquid around them is water, or a mix of water and anything else. As long as the liquid being pumped is compatible with the bellows assembly that seals around the seal faces and lets them float together under tension, and the rest of the materials in the seal itself, that's all that matters. Heck, even if the water/fluid being pumped has abrasives in it, it doesn't matter as long as the seal faces stay under tension, and stay true together, they will continue to seal.

Like I said, I just wanted to clear this up. It seems that the marketers for many items, be it antifreeze, or whatever, make claims about their product that might be true in a given circumstance, but the other 99.999% of the time makes absolutely no difference at all. Still it sounds good, and the average consumer will buy the product for that reason alone, even if the claim has absolutely no benefit in their application.

thats what I was trying to say in my reply below.

I do remember Navistar issuing a service bulletin on some engine where if the antifreeze to water ration exceeded 60% it was causing the water pumps to leak. Might of made it too slippery to seal ? So it can matter.
Pumps were being replaced that should not of been when all they needed was the correct mixture in them.

Your last paragraph reminded me of a TV ad for Mobil 1 motor oil years ago, John Madden claimed, "Mobil 1 gets deep inside your engine and actually coats the moving parts." Correct me if I'm wrong, but wouldn't kerosene do the same thing?

Wayne, thanks for your comment, coming from someone with your experience, I trust your judgement.
One other thought entered my mind, that the seal not only keeps the fluid from leaking out, but it also keeps the fluid away from the bearing. Otherwise, the fluid would wash the lubricant out of the bearings and they would fail prematurely. So actually, their claims of lubricant in the anti-freeze if useless. Am I correct?

"Mobil 1 gets deep inside your engine and actually coats the moving parts."

DUH! Isn't that the primary reason that you put OIL in an engine - to lubricate the moving parts. You certainly aren't going to pour the oil all over the OUTSIDE of the engine. - While the basic statement is true, it was designed for idiots that have absolutely NO CONCEPT of how an engine works.

I know I"ve heard a major problem with the small Kubota diesel engines is the owner using too much antifreeze. The way I understand it, antifreeze in it"s pure form isn"t that great of a conductor of heat, instead, it will insulate. Mixed properly, up to 50/50, it does just what it"s designed to do and carries the chemicals to prevent corrosion, keeps the water from freezing, etc. However anything over a 50/50 and it will act as an insulator and prevent the water from carrying away the heat as well as it does at lower percentages. In turn that can cause the engine to run hotter than normal.

In the case of the Kubota"s, one customer was having problems with the head gasket leaking, and eventually a cracked head. What they told him was that running too much antifreeze was causing the engine/head to get too hot, in turn causing it to warp and, in that case, eventually crack due to the thin walled passages inherent in an engine that small.

As far as why too much antifreeze would cause a problem with a seal, it"s beyond me. I"ve worked with numerous types of mechanical face seals over the years, and beyond the things I mentioned above I have never seen an instance when the fluid being pumped would cause a problem. Possibly in this case it was just what I described here, and the coolant couldn"t cool the seal properly due to the higher percentage of antifreeze, thus causing it to fail.

In every instance I know of, as far as the water pump, your right, the seal needs cooling, not lubrication. Now if you've got a diesel with O-rings sealing the liners, etc, then it may have properties that will help keep the material in the O-rings pliable, and it may do the same for the material in some seals, but as far as actual lubrication, there is none needed.

Too, your right, most water pumps are running sealed bearings, and the seal keeps the fluid away from them. In fact most water pumps have a weep hole in the cavity between the bearings and seal so if the seal does leak, it won't wash out the bearing. This way you can run the engine long enough to get it to the repair shop, etc, as long as you keep water in the system to make up for the leak, without the risk of the bearing going out on the way. That said, what I have seen more often than not is the seal leaking is secondary to the bearings going bad. Basically the shaft looses square with the rest of the housing/the bore. As a result the moving part of the seal is no longer square with the fixed part of the seal, and it begins to leak.

all i can say is thank you.

Hello NCWayne.

Here is a diagram of a raw see water system.

Guido.

I would suspect the high concentrate was making the seal soft/ hard/or cracking.. and once a seal is damaged.. you need a new pump.

There are exceptions where pure water will wreck a water pump seal.
Back in the day (45-50 years ago)we farmed with a pair of Moline model GB tractors.

We ran pure water in them and drained the water in the fall before freeze up. Next spring we would add water and crank them up, usually resulting in an immediate water pump seal leak. We would have to replace pump seals every spring, as the seal bellows would be torn.

It took a frw years to realize that the seal was rusting to the cast iron impeller over winter and twisting the seal loose from the bellows at spring start up, Because the cooling system was drained for 6 months.
We told the kindly old Dealer of our pump seal trouble and he recommended a fix. He sold us small jars of solible oil water pump lube. That worked well, the oily coating on the inside of the cooling system prevented the seal to impeller rusting, so that ended the pump seal damage.

Later when we went to EG antifreeze all year round, that also prevented the seal rusting / sticking.

Yep, straight water, just like most other marine engines, be they outboards, like has been discussed on another thread recently, or on an I/O setup. True, some will run a keel cooler, or run the raw water through a heat exchanger, but there are also plenty of them that run straight raw water also.

I have seen a couple if IH trucks that had V8 gas engines in them that would overheat when the antifreeze mixture was too strong. Simply making sure they had a 50/50 mixture corrected the problem.

If it was the post about the fellow that was ordering a new radiator, I can not figure out why so many posters got so excited. He was going to change out the old radiator. So, what if he used tap water for a week or two and kept adding. There are only a few ppm of minerals. Years ago when it was tough times everybody around here did for the whole season. I do not remember losing one water pump when doing this for the whole season.
I just do not understand what the big fuss is. We
were not putting water in a $35,000 engine.

Wayne, I have repllaced a few cracked V series Kubota heads. I wonder if they are not designed with sone internal passages that are too thin. I can not see the coolant mixture causing this. Still think those Kubota engines are a real good little engine.