For the 2007 model year General Motors (GM) increased the powertrain warranty on its cars to five years or 100,000 miles (5/100), whichever comes first. They felt this warranty was better than Hyundai’s 10/100 powertrain warranty because it transfers to subsequent owners of the car.

Today GM sent a memo to dealers to announce changes to the items covered by the 5/100 powertrain warranty for 2010 model year cars.

Items that are no longer covered include:

1. Fuel system, including fuel pump and fuel injectors

2. Powertrain control modules

3. Throttle body assembly

4. Clutch and pressure plate for manual transmissions

5. Wheel bearings

Items added:

1. Oil lines and oil cooler

2. Crankshaft pulley

3. Clutch master cylinder

First thought: they’re reducing coverage, which isn’t good. The fuel system and wheel bearings are among the powertrain items most likely to fail in the first five years.

Second thought: do competitors’ standard powertrain warranties include these items?

To find out, I called a few dealers and had them check coverage on these items for me. (Note: I did not ask about the crankshaft pulley.)

First off, the powertrain control modules tend to be covered under the 8/80 emissions warranty, and this remains the case with GM.

Beyond this, it turns out that the items covered under the standard powertrain warranty vary quite a bit from manufacturer to manufacturer.

Toyota covers everything in the list except the throttle body assembly.

Honda covers the fuel pump and drive wheel bearings, but nothing else on the list.

Subaru covers the transmission control unit and the wheel bearings.

Hyundai covers only the drive wheel bearings with its non-transferable 10/100 powertrain warranty.

Nissan covers nothing on the list.

Still waiting to hear on Ford.

In other words, it appears that GM’s coverage used to be among the best, perhaps even the best, and will now be among the worst–but that it has plenty of company there.