How does 'Water Pump Lubricant' lubricate the pump?

So anytime I buy antifreeze at the local parts store, they try to sell me water pump lubricant. I dont have noisy bearing in my pump, and my cooling system works fine.

But last time I was there, the guy was pushy and so I stumped him with a question I’d like to know:

“How could the water pump get lubricated if the additive is in the antifreeze?”

I mean, if the additive can reach the bearing of my pump, then I dont need lubrication, I need a shaft seal!

Any thoughts?

Only that you should have caught a picture of look on the guy’s face. =)


If the additive can reach the bearing, then you need not just a shaft seal but a new pump.

Sounds like Jiffy Lube isn’t the only car place trying to sell stuff that nobody needs. You should ask the guy if they have any blinker fluid.

Just another profit generator. As long as you continue to say, “No thanks,” you’ll be fine.

Polybrian: Your analysis and question is right on. I would have loved to see the expression on the tech’s face. The problem is that most people cannot think of the concept as you described it.

Let’s not all get too smug. So a salesman does not know how a product actually works? Big deal. Let’s have all the regular forum members explain LEDs. See what I mean?

Who cares how water pump lubricant does its job. Maybe the antifreeze enters the bearing, bathes it. If this product can truly extend the life of a water pump, preventing emergency repairs, then it’s a good thing to have. Like those guys here who insist on using fresh synthetic oil every 3000 miles, why not? Can’t hurt.

Do you work for Jiffy Lube? :wink:

Yes, it can hurt. I don’t know what water pump lubricant is made of, but it could be made of something that damages the pump / cooling system, gunks it up, reduces the effectiveness of the antifreeze, etc.

And it can hurt your wallet. They’re not giving this snake oil away for free.

While it is possible this stuff does have some small benefit (but I really doubt it), the problem is parts/service retailers trying to push additional products on the public, many of whom don’t know if it’s useful, or just snake oil. There is a reason that the auto repair business has such a bad reputation. Most of these products are just a harmless waste of money, some can actually do damage (i.e., cooling and AC system “stop leak” products).

I found the following on the web. It’s the way I remember antifreezes and common practice at the garages I worked at.

Through the mid ?70s, most antifreeze contained silicate additives which were abrasives that kept the mineral deposits, in the water, from building up in the cooling systems. Because the silicate additives were abrasive, they also destroyed water pump seals. A water-soluble oil was added to the antifreeze solution to protect the water pump seals. This oil was called water-pump lubricant.

If you used straight water in your cooling system during the summer months (distilled water worked best) you also had to add a pint of rust inhibitor/water pump pump lubricant to the water.


Of course, the real solution is to use the correct (OEM recommended) antifreeze in you system, it will already contain the required anti-corrosion and “lubricant.” There is no good reason to use “straight water” in any street car.

I suspect that the additive contains silicon which mixes with the coolant. The coolant circulates around the back side of the exposed pump bearing and lubricates it. I believe this lubricant is becoming less popular and is hard to find since pump bearings are now fabricated as a sealed unit with permanent lubrication. I’d paid the devil to find a source since I maintain old style vehicles and the rebuilt pumps sold today just don’t last very long.