Common Senses

Mack and Volvo director of dealer and customer training Al Herzog checks the dipstick for a rubbery texture – which would signal glycol in the oil – or white froth – which would indicate water in the oil.

In his years as an owner-operator and fleet driver, Lance Gates never listened to the radio in his truck. “You can’t hear what the engine is doing if you’re listening to The Beatles on the oldies channel,” he says. “A lot can go wrong, and you wouldn’t know it.”

Sight is the most significant sense, followed by hearing, but your sense of touch, taste and smell, can also play a role in reducing your exposure to delay, accident and general grief.

Plenty of things can obscure vision – snow whiteouts, fog, malfunctioning headlights.

Sometimes obscured vision can lead you to the discovery of problems with your machine. Take constant fog on the inside of your windshield, for example. “If you’ve got a windshield that fogs and won’t clear, you’ve got a faulty heater core,” warns Al Herzog, director of dealer and customer training for Mack and Volvo Trucks North America. “Don’t be confused if there is no drip on the floor. Most trucks have drip pans now that catch leaks and disperse them.”

This old-timer trick is called the blotter test. Put a drop of oil on a piece of white paper towel. If the oil maintains its black color all the way out to the edge of the stain, according to common wisdom, the oil is holding the soot load well. If there is a green ring, there is coolant in the oil. If the black stain fades toward the edges, you’ve got water in the crankcase. Give this visual test a try if you’re past due for an oil change and want a quick indication of oil condition, but don’t depend on it for exact indications.

Many drivers can listen to an engine and name its manufacturer. The same skills can be put to work to diagnose potential problems. Herzog cautions that turbo noise, even in the new, quieter EGR engines, can easily be misunderstood. “The tighter the clearance between the turbo housing and the turbine wheel, the sweeter the whine will be when it is spooling up,” Herzog says. “This means the turbo is performing well.”

Herzog also notes that it is easy to mistake the whine of a turbo for a hose leak. Checking hoses and the ground under your power plant for leaks is the best idea if there is confusion.

Clutches can also be diagnosed by ear. The rattle of a throw-out bearing that is going bad can be heard in pull-type clutches when the clutch pedal is depressed. Push-type clutches will make the same sound in neutral, Herzog says. But whether you hear the noise with your gearshift lever in neutral or with the clutch depressed, that rolling rattle means future problems.

The rear carrier bearing can whine as well. Herzog says that in single reduction rears like Eaton and Rockwell systems, “That whine in neutral can mean that your shift pattern is out of adjustment. In dual reduction rears like Mack’s, a whine probably means a worn power divider.”

“Any time you have multiple components, finding one hotter than the other means you’ve got a problem,” Herzog says. A difference to the touch in the heat generated by rear and front carrier bearings can signal the need for a closer look by a technician.

This is also true of wheel ends and brakes. “If you find one wheel end hub hotter than the hub at the other end of the axle, you’ve got a bad bearing or a brake that is out of adjustment,” says Randy Dunn, an owner operator leased to Universal Am Can. Your steering hubs ought to be a frequently checked spot. A simple touch after running hard can tell you whether you’ve got a hot bearing.

Feeling ridges, ruffles and any unevenness in your tires is a dead giveaway to future bald spots and premature failures. A visual confirmation can be done after the hands-on.

“If you’ve got a leaking wheel seal, you can smell the hot grease,” Dunn says. Hot oil can smell pretty pungent as well. Herzog notes, “The baked smell of burnt oil under the hood is a strong indicator you’ve got oil weeping onto on the manifold or head. You can smell it before it starts to smoke.”

It is also possible to smell fuel in the radiator, says Dunn, which probably means a cracked head. A sweet smell under the hood means you’ve probably got a coolant leak. Herzog warns that this may mean there is coolant in the oil. He suggests looking at the dipstick to check for the telltale rubbery texture of oil that signals the presence of glycol. Seeing white froth on the stick means you’ve got water in your oil.

The more dedicated among you may put a drop of oil on your tongue to taste for glycol, which is sweet and may be an earlier warning of glycol in there than a rubbery texture. By the same token you can crack a cold radiator and taste a drop of glycol for fuel. Dunn, who has been trucking for a long time, says he has done this and lived. If you try this at home, make sure to spit.

Dan Larkin, a technical consultant and president of D&L Lubricant Solutions, thinks tasting oil is poor science and does not recommend it. But he says if you’re going to do it, do it right after shut down. “This is when the pressure in the coolant system increases and the oil pressure drops,” he says. “Since there is more pressure in the coolant system, any bad gaskets will allow the coolant into the oil system since the pressure of the coolant is greater than the pressure of the oil. Still, there would have to be a lot of coolant in there to taste it.” It is always best to check with a professional technician to prove or disprove your suspicions, Herzog says.

Tips For Using Your Senses

  1. Listen to your engine when it is healthy. It is by comparing that sound to the sounds it makes before breakdown that you’ll hear problems.
  2. Baseball hats pulled low on the forehead can hide low obstacles. Consider raising the bill of your cap in tight places.
  3. Learn to distinguish between healthy turbo sounds and sounds that are harbingers of failure.
  4. Upgrade your walkaround by doing another one halfway through the day. Use your hands to search for problems like hot brakes, hot bearings and leaky seals. This is the time heat and smells will be most obvious since you’ve been running hard.
  5. Take special care with steering axle hubs. Finding a potential problem here well in advance of a bearing failure could save your life. Use your hands and sense of smell to search for telltale signs of heat.
  6. Once a week, grab a flashlight and use your hands to examine tire tread. Check out any inconsistencies in the tread visually.
  7. Remember, multiple components should run at the same temperature. Finding an axle end hotter than the others is a sure sign of imminent failure.
  8. Check your coolant for oil and fuel when the radiator is absolutely cool.
  9. Check your oil for glycol.
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