Water Pump Grease – Dave’s Garage

A lot of our antique cars have, or had a grease fitting or a grease cup on the water pump. Without the proper grease, the water pump bearings will quickly fail. In some cars, particularly Model A Fords, the grease may pass through the water pump in to the cooling system. Ford specified a special water soluble grease. Using a conventional grease can cause a blockage in the radiator. Chrysler specified a special grease for use on their water pumps too.

water pumpSo, what makes water pump grease different than conventional chassis grease? Depending on the grease, it is either a grease that won’t be washed away by water, or a water soluble grease that will wash away and dissolve in water preventing a blockage in the cooling system.

Many replacement or rebuilt water pumps have modern, sealed bearings. Most of these pumps use the original casting and either have a grease fitting, or grease cup, or a spot for the grease fitting to be fitted. Many concourse restoration pumps actually have dummy grease fittings or grease cups to “look the part” of the factory pump.

The question is, what grease to use? If you need a water soluble grease, such as for a Model A, most Model A parts- houses stock the water soluble water pump grease.

There are several options for non water soluble grease. Most auto parts stores stopped stocking water pump grease decades ago. The most popular modern replacement is marine grease, or the wheel bearing grease for boat trailers. Many people use Lubriplate 115 for water pump grease. Marine shops carry outboard motor grease. Another option is your local fire department. The pumps in fire trucks requires a special, water pump grease. This grease is sitting right on the shelf at the fire house. If you are lucky, they may give you a few pumps from their grease gun, or several ounces from the tub they are using.


Please email all inquiries to: Dave
or snail mail
32 Turkey Hill Road
Richmond VT 05477

2 thoughts on “Water Pump Grease – Dave’s Garage”

  1. Good afternoon, I have a 1927 Chev. coupe.. Can you help me find a nowday replacement grease that would work for the water pump…I’m not sure if the car requires a water proof or water soluble grease…. Thanks any help will be appreciated…. Bill

  2. Good morning,
    I believe the proper grease for your water pump is water soluble grease. I did some digging on your specific pump, and found this article from “The Filling Station”. There is a lot of helpful information here. Also, if you ever have your pump apart, there is a baffle behind the pump. Early ones were steel, which rusted and caused overheating issues. These were replaced with a brass baffle.
    “ Early Chevrolet water pumps from 1916 thru 1937 have bushings that require constant maintenance. This style of water pump needs lubrication: oil on the pulley bushing every 50-100 miles & water pump grease from the grease cup around every 100 miles. In addition, whenever leaking is noticed, the packing nut should be checked and tightened. If the packing nut is turned all the way in, it will be necessary to add a ring of packing and readjust the nut. Failure to properly maintain this style of water pump can cause failure of the bushings, and leaking that cannot be stopped. At that point the only option is to rebuild or replace the water pump.

    Each time these early cars & trucks are driven, it is vital that the water pump is lubricated. In the front of the water pump snout, there is an oil galley. Sometimes this has a metal, spring-loaded cap on it and sometimes it is just an open valley. Put a few drops of oil on this bushing each time the vehicle is run. A fan belt that is too tight can damage the front bushing and cause it to fail. It is important that the fan belt is left as loose as possible while still making the fan move. Over-tightening of the fan belt can cause premature failure of the front bushing. KEEP THE BELT LOOSE and the water pump will last longer.

    The water pump packing nut squeezes water pump packing around the shaft to prevent leakage. It will also prevent air being sucked into the impeller of the water pump. Air around the water pump impeller will cause cavitation and prevent circulation of water causing overheating.

    If leaking is noted, turn in the brass packing nut with a 1″ open end wrench until the leaking stops. Caution: over-tightening this nut can cause the shaft to seize. If the packing nut is turned in all the way, back out the nut completely and add a single split ring water pump packing into the cavity. Start the packing nut back into the housing being cautious that it is not cross threaded. Tighten the nut until the leaking stops.

    Finally, the grease cup should be turned in around every 100 miles. A proper water pump lube should be used in the grease cup.

    Let me know if you need more info,
    Be well, David.

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