On the Road

Leaky Roofs, Plugged DPFs and a Rainbow of Coolants: TMC Tackles them All

March 3, 2016

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Photo by Jim Park
Photo by Jim Park

The 60th annual meeting of the ATA's Technology & Maintenance Council wrapped up in Nashville Thursday with the Shop Talk & Fleet Operator's Forum session. As usual, it's one of the more revealing sessions at TMC and one unique to this convention. It's where fleet participants get to raise issues they are having with their equipment in a forum with their colleagues and competitors – and even their suppliers.

The fur has been known to fly during this session, but with TMC's strict anti-trust guidelines, participants are not allowed to name names, thus to some extent protecting the names of the alleged guilty parties.

Everyone goes away a little wiser and no feelings are hurt publicly. In other words, it's a great way to share some experiences without fear of running into legal troubles.

Everyone goes away a little wiser and no feelings are hurt publicly. In other words, it's a great way to share some experiences without fear of running into legal troubles.

What we learn from such discussions is that you probably aren't the only truck owner having a particular problem. It puts the boots to the oft-heard comment from dealers, "Gee, I've never heard that one before."

For example, a simple show of hands in the room revealed that about two-thirds of the roughly 300 participants were having problems with leaky cabs – roofs, windshields, doors, external connections on the sleepers and cab firewalls, etc. One complained of wading through inch-deep water in the sleeper after a thunderstorm, while another said "water poured from the driver's door when it was opened."

That sounds extreme to me and it might be an exaggeration, but I certainly didn't see the truck and so can't support or refute the statement.

While the leaks are bad enough, many claimed the water was running into the cab and finding its way, as water often does, to the most inconvenient places, like power distribution panels and firewall connections. There, it's causing corrosion and the corresponding voltage and impedance irregularities that sensitive electronics respond so well to. In short, a leak that affects an electrical or electronic connection can be a mission-crippling problem.

So, if it makes you feel any better (misery loves company, they say) if you have water egress problems, you're not alone. The OEs, or some of them anyway, are having problems with this and need to address it. TMC is aware of it and so are about 300 other fleet maintenance people. You're not the only one out there with wet feet.

Clogged DPFs

Another consistent source of aggravation is the aftertreatment system, in particular, clogged diesel particulate filters. Again, a show of hands revealed a significant majority of the fleets in the room had experienced out-of-the ordinary difficulties with DPFs. ranging from a "no problem found" diagnosis after the truck had been in the shop for an extended period of time following an undiagnosed complaint, to too-frequent intervals for regen or DPF cleaning.

We heard some fleets say they have had DPFs replaced twice under warranty before the truck was traded out on its third DPF. Some fleets said they had invested in their own DPF cleaning machines and that a full cleaning at 200,000 miles had gone a long way toward reducing the need for roadside regens. While that's a considerable expense, it's a good way to manage an otherwise nearly unmanagable problem.

DPFs are rapidly becoming the bane of the fleet manager's existence, but in most cases it's not a manufacturing problem.

It's just a fact of life that requires additional problem-solving and equipment management resources -- and in many cases, additional driver training.

It's just a fact of life that requires additional problem-solving and equipment management resources -- and in many cases, additional driver training.

Demands for regens are very much application driven, so some will see more regen cycles than others. There are no standards when it comes to regen intervals, but when drivers unfamiliar with the equipment get involved, things can only get worse.

One fleet maintenance manager recalled a driver who was extremely angry about have to do at least one regen on his truck every day. A little investigation revealed the driver was mistaking the High Exhaust System Temperature lamp for a regen required warning. When asked how the driver responded to the HEST lamp, the driver said, '"I pull over to the side of the road, I let the engine run 'till it shuts off, I restart it and I'm fine for the rest of the day."'

Clearly, drivers need a reminder once in a while how to respond to a regen request, and with new drivers entering the industry every day, there seems to be a real need for ongoing or remedial training.

As well, some in the room pointed out the need for proper air intake system maintenance to keep foreign material from entering the engine and eventually the exhaust stream where it can contribute to DPF clogging. This includes oil and coolant leaks. Both are detrimental to DPFs.

So, while the system itself is high maintenance by nature, if other problems are going undetected and unreported by drivers, such as high incidences of adding make-up oil or coolant, you could be facing additional maintenance headaches and increased downtime because you have a problem than nobody is telling you about.

Rainbow Coolants

Speaking of make-up coolant, the mix of coolants on the market today is causing untold headaches. With so many varieties on the market in so many different colors (not all coolant producers have adhered to TMC's voluntary color coding standards), drivers and technicians are mixing coolant types more often than we'd like to believe. This isn't always a serious problem, depending on the blend, but it can lead to problems if concentrations of different non-compliant coolants get high enough.

One problem that was discussed in some detail was the presence of an ammonia smell to the coolant. It's not, as some believe, an indicator of diesel exhaust fluid in the coolant.

One problem that was discussed in some detail was the presence of an ammonia smell to the coolant. It's not, as some believe, an indicator of diesel exhaust fluid in the coolant.

DEF does have a slight ammonia smell, but in this case the smell is caused by a reaction between the flux used in the manufacture of the radiator and the additive package in some non-compatible coolants.

The state of confusion with coolants today is such that TMC is looking at revising its some of its coolant-related Recommended Practices and even scheduling some tech sessions or webinars dealing with coolants.

Coolants don't appear to pose any serious problems at this point, but when a room full of maintenance experts express concerns and want to ask questions, we can assume there is some lack of clarity on the subject.

There were a number of other issues discussed during the final session of this year's TMC meeting, but these three caught my attention because of the sheer number of people whose hands went up when asked if they were having trouble. And remember, these folks are the more enlightened among us, the ones that take the time and trouble to attend and participate in TMC. There are thousands more out there struggling on their own, and perhaps being told they are the only fleet experiencing such a problem. Chances are that's not the case, but how would you ever know for sure?

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Author Bio

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Jim Park

Equipment Editor

Truck journalist 13 years, commercial driver 20 years. Joined us in 2007. Specializes in technical/equipment material (including Tire Report), brings real-world perspective to test drives.

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