Ford replaces turbo because of pre-ignition detonation

Ask the Auto Doctor

DEAR DOCTOR: My 2015 Ford Fusion with the 2.0-liter turbocharged engine is at the local Ford dealership for a new engine, due to a piston breaking from a low speed pre-ignition incident. Luckily, the failure occurred at 59,000 miles, so the new engine is covered on the 5-year/60,000-mile powertrain warranty. What do you know about this issue? I’m told it’s pretty much unique to turbocharged direct-injection engines?

— John

DEAR JOHN: Pre-ignition engine detonation can cause major engine failure. There are many potential factors involved in causing this problem. On older vehicles it’s from over-advanced ignition timing, an engine running hot, a lean condition, or use of wrong fuel octane. The new direct fuel injection engines can suffer from a lot of carbon buildup, causing hot spots on the piston tops. Dirty fuel injectors can also have an irregular spray pattern. Low fuel octane is also another condition. Infrequent oil changes and the use of an incorrect oil will contribute to internal faults, as well as camshaft valve timing. Leaking cylinder head gaskets will also cause internal piston problems.

DEAR DOCTOR: My 2010 Scion tC has only 46,000 miles and is wearing out the inner brake pad on all four tires. The outer pad shows no real wear. I have used a special brake pin grease, Sil Glyde, thinking the pins were sticking. I changed the pads three times within the last 14 months while only driving about 6,000 miles. Prior to doing the last set, I used a small pry bar to slightly compress the piston and see if the calipers would slide on the pins, which they did effortlessly. I have also changed all pin seals and brake pad clips. Is it possible all four calipers are worn out?

— Frank

DEAR FRANK: For one side of the brake pad to wear indicates the pad is not moving away from the rotor. A sticking caliper piston would cause both inner and outer pads to wear. I would check the caliper side pins and caliper bracket for wear. The brake pad must slide freely and sit correctly. When we perform a brake replacement, we always clean and grind away all rust, as well as replace all of the brake hardware. We always use a general purpose marine grease on all contacts.

DEAR DOCTOR: I’m the original owner of a 2004 Honda Accord V-6 with 165,000 miles that’s maintained on a regular basis. Recently I’ve noticed my transmission slipping, but only when I drive the car in the morning. After a mile or so it seems fine and remains OK throughout the day. I had it test-driven by a transmission technician and he also noticed the slippage. I was told flushing the system may make it better, but could also make it worse. Letting the car warm up for five minutes sometimes alleviates the problem. Any suggestions?


DEAR VICTOR: The automatic transmission has been a recurring issue on Honda vehicles. The reason for the slippage on a cold drive is the internal seals are hard and fluid slips by, causing internal pressure loss. I would change the transmission fluid, using only Honda fluid. The new fluid might offer enough flow that the problem may go away. To change the fluid you have two choices: use a flush machine, or, drain the fluid manually from the drain plug. If you are going to use the drain plug, then it will have to be done a few times. When draining the fluid only 3 quarts comes out, so this will require four drain and fills.

Damato is a certified ASE mechanic.


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