Tech Tips

TPMS

Tire Pressure Monitoring Systems are increasingly on everyone’s minds, but you do have to be careful when servicing vehicles equipped with TPMS, which is all vehicles manufactured since the 2008 model year.

I’m writing this tip as a warning to everyone who performs tire rotations and balancing. While those of us who offer this service know the cost of the lifts, jacks, tools, weights, etc. involved, we’re also familiar with the profit it can bring.

TPMS was mandated by the government in something called the Transportation Recall Enhancement Accountability and Documentation, or TREAD, Act, which mandated that all passenger vehicles (excluding motorcycles, dual-rear-wheel trucks and vehicles with a gross vehicle weight rating of more than 10,000 pounds) be equipped with TPMS. These systems will alert the driver any time tire pressure on a particular tire (excluding the spare) falls 25 percent below the recommended inflation pressure, or rises to 45 percent above the recommended inflation pressure when running. A light on the dash of these vehicles will stay illuminated until the condition is cleared.

The kick in the butt of all this is that, other than those general guidelines, the government gave automakers no direction or standards to follow. This means every automaker will come up with its own method of monitoring tire pressure — and resetting those monitoring systems.

A “typical” TPMS will measure tire pressure and temperature before transmitting the coded data to the vehicle’s computer every 20 to 40 seconds. On many vehicles, each sensor will have a unique idea to allow the computer to identify which tire is suffering from pressure problems.

Many automakers are using wireless systems that transmit the data via a low radio frequency (315 to 434 MHz) to a receiver in the vehicle. Quite often, the sensors themselves will be mounted inside the wheels near the valves.

In most cases, these sensors will only be triggered when a vehicle is in motion, usually faster than 15 miles per hour for five minutes. Most sensors “sleep,” or cease transmitting, when the vehicle is stationary, conserving battery life (which was optimistically expected to last seven to 10 years when the systems were designed, though street-level experience is showing lives closer to five years).

There are several tools that will allow lube operators to continue performing tire rotations/balancing. These tools will allow the sensors to be reset after tire rotations, so the computer doesn’t indicate that the left front tire is low when it’s actually the (post-rotation) left rear.

In the meantime, be very careful about rotating tires on late-model vehicles, and study the owners manuals of these vehicles for tips about resetting the TPMS.
Oh, one last thing. Early indications are that a number of sensors will fail in everyday use, and dealerships are expecting to charge between $50 and $200 to replace them.

Smart-O Drain Plug

Ordinarily I shy away from writing technical tips about specific products, but in this instance I couldn’t resist. Oil leaks caused by loose or damaged drain plugs have long been an operational challenge for lube operators, but I recently finished testing a new product called the Smart-O drain plug and found it to be something that could take the worry out of replacing a loose or damaged drain plug.

The Smart-O has a groove cut into the threaded portion of the drain plug, a groove that holds a specially engineered O-ring. Once this O-ring comes into contact with motor oil and heat, it expands up to 10 percent, creating a seal between the threads that helps prevent leaks — especially handy in the case of a damaged plug.

These plugs are a little tough to install and uninstall, owing to the O-ring, but they can be used over and over.

Chevrolet Heli-Coil

Editor’s note: This question-and-answer tip is from our Lube Chat forum, accessible on our website at: noln.net/forum.php

We serviced a 2009 Chevy Silverado with 6,000 miles a few months ago. The customer went back to the dealership to get her next oil change. The dealership told her that someone installed a heli-coil improperly, and that it came out. Of course, she said it was us.

We do not install heli-coils. I thought all Chevrolet 5.3L engines are factory-fitted with heli-coils in the drain pan, but I can’t find any documentation.
– David

Yes, all GM 5.3L engines are fitted with a heli-coil from the factory. We have also had the heli-coil come out with the drain plug, probably due to the plug being over-tightened at some point. The repair is to simply install a new heli-coil if you have the kit to do so, or install an oversize drain plug and cut new threads in the oil pan.
– Mr. T