Bottom Line
Maintenance Q&A
The basics - tires, batteries and oil

Paul Abelson
Senior Technical Editor

Question: My company has been having a lot of problems with Goodyear G397 LHS steer tires falling apart well before they should be, usually by separating at the outer groove. These tires were installed new at the International factory on 9400 tractors with ISX motors.

These tires are sold on the market as a “super” long wearing tire, yet we never get more than 100,000 out of one before they separate. Many were going bad at just over 50,000 miles.

Did we get a bad batch, or is this common? I usually try to replace them with G395s — those have proven to be a more cost-effective tire here.

Answer: I checked with Al Cohn, a TMC Silver Spark Plug and Goodyear marketing manager responsible for International. He said, “It sounds like he is having defense groove tearing (outside rib shoulder tearing). That does not mean they are falling apart. It means that the tire is not designed to hit every curb ... it was designed for pure line-haul service.”

I also went to the TMC Radial Tire Conditions Analysis Guide, Recommended Practice 216B. It identified the condition and included a photograph. The RP states that the cause is “running over curbs or rails, or by severe localized impacts, aggravated by sharp turning.” The recommended action is, “If steel is visible, contact your tire manufacturer. If steel is not evident, retread or return to service in a dual position.” A further recommendation is to “review tire selection and driving procedures.”

Al continued, “As he states in the bottom of the note, the G395 LHS will do a much better job for his application.”

Question: (From the OOIDA Maintenance Forum) I put new batteries in my truck back in November 2002, and use an inverter for my accessories when I park. I hate idling.

My batteries are showing signs of not holding a charge, as I can’t leave my truck shut off for more than two hours without the low voltage warning on my inverter going off. I used to be able to shut the truck off all night without a problem.

How long, on average, do your batteries last on your truck? I’m considering going with Optima batteries when I change them.

Answer: If you hate idling, I assume you use your batteries to power your HVAC (heating, ventilating and air conditioning) and “living” needs, and you are not using shore power. Whether through your inverter at 120 volt or direct at 12 volt, the current comes from the electro-chemical reaction in your batteries. The reaction is reversed when your alternator charges your batteries, but the batteries’ ability to accept a charge is limited by cold temperature. The colder the batteries are, the less current they can accept.

Car batteries are under the hood, where they are warmed by engine heat. Truck batteries are left out in the cold, behind the cab or in a box on the frame rails. During winter driving, they do not accept enough current to be fully recharged. Imagine a pitcher of water 100 percent full. Pour out 40 percent (what you need to get through the night) then refill it with only 38 percent. Next night, pour another 40 percent, and then add back only 39 percent. Day after day, the cycle repeats. Little by little the battery is weakened. Eventually it does not have enough reserve to power your “hotel loads,” the lights, fan, fridge, TV and other electrical loads you put on it with the engine off and then start your engine. Internal damage includes flaking of the batteries’ plates, further weakening the batteries’ ability to accept a charge.

Optima (and other AGM — absorbent glass mat — batteries) use a different construction to minimize the flaking and maximize chemical contact inside the batteries. They will give off current more efficiently, but they are not the answer to every battery problem. There are some well-researched posts on the OOIDA Maintenance Forum in response to this question.

Starting batteries have thin plates that provide more surface area for a rapid high-amperage discharge, as in starting. Deep cycle batteries are designed with thicker plates to release lower amperage over a prolonged period. You can combine starting and deep cycle batteries, but they charge at different rates. Battery isolators shift charging current to each type as it is needed.

Question: How far are we from on-board oil analysis? I read recently where I think GM has a system in some top-of-the-line Cadillacs that monitors the oil for breakdown. It then indicates when oil needs changing. This is not like the old systems that simply monitored the mileage since last oil change. 

These actually analyze the oil for breakdown. The statement was made by some experts that as we are used to changing the oil every 3,000 miles or three months, with the advances in oil technology we have been discarding millions of gallons of good oil every year. They say depending on driving situations, many cars could go 4,000 or 5,000 miles further. I know pulling oil samples and spending $15 on analysis will do the same, but with today’s technology, it would seem logical that they could put on-board systems on trucks. Any thoughts on this? Paul, has this been brought up in any TMC meetings?

Answer: The systems on GM and other four-wheelers are not true oil analysis. They measure dielectric coefficient of the oil (the ability to pass current) between two electrodes, and its viscosity. Oil’s dielectric varies with soot and metal particles in the oil. The systems also factor in mileage and fuel consumed since the last oil change. They use a mathematical formula to project when oil should be replaced while leaving a margin of safety. I have such a system on my Saturn Vue, but I still use premium oil and change it at 5,000 miles, before being told to by the computer.

True oil analysis is a maintenance tool. It gives you a snapshot of what the condition of the oil is, and indicates what relative wear has taken place since the last oil change. Just as a motion picture is a series of still photos played back rapidly so that the eye processes them as continuous movement, a series of “snapshot” oil analyses can be used to give a moving prediction of when oil should be changed.

Use a spreadsheet program like Excel or QuatroPro to graph your results. Use parts-per-million (ppm) or percent on the vertical axis, and miles on the oil or the engine on the horizontal axis. If you just want to track engine wear, plot sample results every oil change. If you want to extend oil drain interval, pull a sample at your original drain interval, then at half-intervals thereafter. When you plot the results, you will see increases in each measurement.

Critical things to look for are soot level (percentage), iron (ppm), and critical metals, chromium, tin, copper lead and aluminum. Iron comes from cylinder liners, valves and cams. Tin is the first to wear from bearings. Lead and copper indicate bearing wear. Chromium is from rings, aluminum from pistons. Track both Total Base Number (TBN), the oil’s reserve acid-fighting alkalinity, and Total Acid Number (TAN), the amount of acid that has made its way into the oil. If it appears that TAN will exceed TBN before the next sampling period, that’s a signal to change oil.

There are go/no go results that will raise flags immediately, such as fuel, water or coolant in the oil or too high a soot reading.

Don’t forget to record any make-up oil you have added. If you want to get very sophisticated, you can adjust for the add-oil. Usually, that’s not necessary unless you added fresh oil shortly before taking a sample.

The TMC Recommended Practice on Oil Analysis, RP-318B, does not yet address on-board analysis systems. I will bring it up to the Study Group chairman.

Paul Abelson can be reached at truckwriter@anet.com.

Maintenance questions?
You can write to Paul Abelson, senior technical editor, in care of Land Line Magazine, PO Box 1000, 1 NW OOIDA Drive, Grain Valley, MO 64029; or you can fax questions to (630) 983-7678; or e-mail them to truckwriter@anet.com. Please mark your message Attention Maintenance Q&A. Although we won’t be able to publish an answer to all questions in Land Line, we will answer as many as possible.

March/April
Digital Edition