while I was driving the engine began sounding really loud and rough

1997 MERCURY MARQUIS
170,000 MILES • 4.6L • V8 • AUTOMATIC
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JONNYR910
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  • 1 POST
It just started out of nowhere it started sounding really rough and sounded loud something like a tractor. Mechanic said the timing belt was about to pop and also that the pistons were bent so it would be an expensive repair. so i'm trying to get a second opinion.
Jun 11, 2020 at 10:52 AM
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KASEKENNY
  • AUTOMOTIVE REPAIR CONTRIBUTOR
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This is hard to figure out without actually looking at the vehicle however, based on what you are saying this mechanic found, the timing belt most likely jumped timing and allowed the pistons to hit the valves. This will bend the valves and possibly the piston connecting rods.

So if the engine is knocking loudly and it happened all of a sudden I suspect this is what happened. It may be worth while to take it to another shop so someone can put their hands on it.

However, if you want to try and figure this out we need to use a borescope to look down in the spark plug hole to see if there cylinder walls are damaged and if the pistons have marks on the tops of them from where they hit the valves.

Let me know if you have questions. Thanks
Jun 11, 2020 at 5:40 PM