The MDX started to miss, the engine light came on, and the car was putting white smoke out the tailpipe. I went back to look at the smoke and it had the sweet smell of antifreeze. The car smoked less as it was driven but still smoked at idle. Took the vehicle to the Acura dealer and told them I had an antifreeze leak into the cylinder and to look for a blown head gasket. They said these engines don't blow head gaskets.

hey called me back and said cylinder #4 was misfiring and was oil soaked. They asked to continue to investigate. They said the smoke was oil, not antifreeze. Well, I have been working on cars before these technicians were born. I told them to stop working on the vehicle and I took it home. On the way home (3 miles) it used 3 cups of antifreeze. I drove the vehicle once a day and kept track of the coolant usage. I stayed between 2.5 and 3 cups every 3 miles. I took the plugs out and cylinder #4 looked like it was oil soaked, until the antifreeze dried off, then it looked dark but not from oil. I put my endoscope into cylinder #4 and saw beads and small pools of blue antifreeze and the piston looked as though it had been steamed clean. I looked in cylinder #1 and it had a light carbon layer you would expect at 100,000 mi.

So I put other things on hold and pulled it apart. Cylinder and head area was really clean and the rest were carbon coated as expected. The MLG (Multi Layered Gasket) Head Gasket looked like new. Took the heads in for checkout and a crack was found over cylinder #4 that went through the coolant jacket and into the intake valve area. This is where the coolant was getting into the cylinder, not oil from the valve seals. I bought a new head from Acura,and am putting it together this week. I will update this when the vehicle is running.

This is the same problem reported on the 2006 Honda Ridgeline and they should be reported together.

Update from Apr 26, 2014: E-mailed the service writer manager at the Acura Dealer and and described the problem. I received no response from Acura.

It would be a safe bet that most of the repairs done because of an "oil fouled spark plug in cylinder #4" are really a result of a cracked head. The photo I supplied looks nearly identical to the photo under the Honda Ridgeline complaint section.