360 Intake tubes blown off the manifold

This is not an issue with my car - it concerns a friend's car in NJ.

It's a 2003 360 coupe, dealer serviced. One day he was driving and he heard a loud POP with tons of white smoke coming from the engine bay. When inspected, the intake tubes both popped off the manifold.

It's hard to diagnose from afar, but after learning that the dealership just changed the oil a few days earlier, I mentioned they may have overfilled it. He shipped it back and sure enough it was over a quart overfilled. They drained the oil and replaced the clamps.

Now, once again, this weekend he called me with the same problem. Car on the side of the road, both intake tubes blown off.

Has anyone experienced this? It's possible that they overfilled it again, but it sounds like a backfire of some sort.

Again, it's nearly impossible to diagnose without the car being here. But, now that it's a recurring problem, I figured I'd see if this has happened on any other cars.

 

Interesting.

I'm a bit concerned that it happened twice to his car. Wondering what would cause the backfire - mixture issue or timing? Mixture would likely trigger a CEL, but possibly timing? Valves closing too early, building up unspent fuel? Just spitballing.

Knock on wood, I drive mine every day - city, long highway trips, etc. Hasn't happened to me. It runs the same every day, regardless of temperature, etc.