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Spray Washer Maintenance Tips

Isn't it ironic that we're in the business of rebuilding engines - commonly a result of neglect or age, mileage or service - yet often we fail to maintain the very equipment used in the rebuilding process? A perfect example is the jet spray washer. How often do you perform maintenance on yours? If the answer is "not often" don't be ashamed: you're not alone

By Brendan Baker

In the 2003 Engine Builder Machine Shop Market Profile (Engine Builder, June 2003), shop owners said cleaning/disassembly were their most time consuming parts of the rebuild process. Survey respondents said that 13.8 percent of an average rebuild is spent in this area, down 2 percent from the previous year. In the same survey, 80 percent of machine shops reported owning aqueous jet spray washers. Part of the efficiency increase is likely attributable to the automated jet spray washer and its growing influence in machine shops. But how long those efficiencies will continue may be a question - the survey also pointed out that the average shop's spray washer is over ten years old.

While the basic design of jet spray washers has not changed much over the last several years, there have been subtle improvements to the equipment. The biggest advances in aqueous cleaning have been on the chemical side of the fence. One factor that has changed over the past few years due to new OHC engine designs is the amount of aluminum now being cleaned. Most chemical manufacturers have kept up-to-date with the industry's cleaning needs, and new solutions for multi-metal and aluminum cleaning usually include rust inhibitors and silicates to protect iron/aluminum.

A jet spray washer has been called many things: dishwasher, spray cabinet, automated washer cabinet, etc. All these descriptions basically mean that the systems used for washing parts are typically cabinets that you can place parts in, set a timer and walk away. A turntable or rotating spray arm surrounds the parts with an aqueous cleaning chemical solution, rinsing away the dirt and grime from a greasy engine part.

The machines clean the parts, but it is up to you to maintain your machines. So we have put together some tips from various manufacturers to help keep your cleaning equipment in tip-top shape.

Daily Maintenance

It is important to monitor fluid level because evaporation can expose the heating element to air, which can burn it out very quickly. Always remember to check your solution level and concentration in the morning before you start. Many new models have built in alarms that warn you when the solution is too low, but if you don't have one with an alarm you'll have to monitor it religiously. Checking the chemical is like checking your pool or hot tub - a simple dip test will tell you the chemical concentration and what the pH level is. If it is lower than optimum you may "sugar" the solution as necessary. Some manufacturers recommend adding a pound or two of powdered chemical a week to compensate for evaporation and diluted chemical charge.

As you clean, the grease and oils emulsify in the heated solution. This doesn't mean it is gone. The grease is still suspended in the solution and if it's skimmed or filtered, the chemical lasts longer. It is best to run the skimmer at a time when the solution is the coolest. Depending on how dirty the parts are and how much you clean, you may find it best to do nightly or weekly.

Visually inspect your nozzles for clogging. Just like the inspection your car gets during a lube/oil/filter, you should check your nozzles at the same time that you're monitoring the fluid level. It's a good idea to lump several check points into one routine, therefore saving time and ensuring everything is checked regularly. If you have a filter you'll get most of the large debris, but it doesn't take much to clog a spray nozzle. Nozzles tend to clog with large chunks of debris (e.g., silicon, paint chips or metal). Without inspecting them frequently, you may not know if one is clogged because the solution will bypass the clogged one for the next open nozzle.

Watch your temperature. Most machines have seven-day timers and a digital or analog temperature controller. This doesn't mean they're foolproof. In the morning when checking the charge, dip a thermometer to see that the solution is actually the temperature the thermostat says.

Seven-day timers can be set to bring the bath up to operating temperature before the workday begins and automatically shut it off at some point during the evening. Jet spray washers typically work best when the chemical is heated to a range between 140° - 190° F. If you open at 8 a.m., set the timer to fire up the heater at 6 a.m. You can also set the timers to skip the days the shop is closed.

Weekly Maintenance

A weekly or monthly maintenance schedule will likely include your other equipment as well as your spray washer. Some maintenance items will only need to be performed once a month but if you clean a large volume of very dirty parts you may need to include them in a weekly routine.

If you're not checking your chemical charge on a daily basis it should be checked at least once per week.

Turntables need to be greased liberally to help prevent solution from getting in. There is usually a grease fitting on the side of the bearing so you can use a grease gun. Any rotating part in a spray washer likely will have a grease fitting. These should be greased at least once a week because the bearings are under constant exposure to chemical, which by its nature, will remove the grease. Some manufacturers recommend this be done daily.

The heating element should be checked regularly, either monthly or weekly depending on how much use the machine gets. Because heating elements are submerged in chemical, if it's made of steel corrosion can build up, creating an insulation effect. Sludge can also build up on heating elements, having the same insulating effect. The result is that the solution will never achieve the optimum cleaning temperature. If you're having difficulty getting the solution up to temperature the element should be one of your first checks.

Clean out spray nozzle manifolds. Again, this depends on usage, so it is possibly a monthly check for light-duty units. Remove the manifold end caps and flush the manifold out with water or compressed air. This will remove any large trapped pieces of debris such as silicon.

Remove the filter basket and clean thoroughly. Cleaning greasy parts every day can quickly clog filters and nozzles. The filters are your first line of defense so most of the large debris will have been caught in there.

Cleaning the Tank

On a less frequent basis you'll need to clean the tank out. Some spray washers are combined agitating hot tanks as well. Eventually, you'll need to do more than just "sugar" the chemical charge. It is a good idea to occasionally empty the tank and clean all of the sludge that builds up at the bottom and around the pump and heating element. However, be very careful not to bump or damage the heating element or you risk voiding any warranty you may have. Also be careful if you choose to try and clean the water level sensor. Some sensors are designed to send an electrical signal only when submerged in liquid - if there is sludge or scale buildup on the sensor, just wipe it clean and leave it alone.

Because the average age of most of the spray washers out there is approximately ten years old, it is important to keep up with maintaining them. A ten year old spray washer can be compared to a ten year old car. There may still be a lot of life left, depending on how the owner takes care of it, but it's far from new. As they approach their teen years, older washers need to be checked and inspected more frequently to ensure continuous operation.

According to one manufacturer of cleaning equipment pumps lose performance after so many years of use even if well taken care of. The environments that a pump has to operate in is very abrasive, with dirt, metal chips and other abrasive particles flowing through it. So a ten year old pump may only be at 50 percent efficiency. But remember, at ten years old, the unit has already more than paid for itself.

Remember, good maintenance is not something you go from zero to 60 mph with. You have to build up those maintenance skills and make them a habit in order to reap all the benefits. A good time to instill those skills is in the beginning. Since most people who start out in the industry start in the cleaning department, it is the best place to mold a start up employee on the finer points of spray washer maintenance. By the time that employee gets promoted to other departments he will have formed a regular habit of maintaining your shop's equipment.