S60, 2.4, 2002, Timing Belt Jumped/Slipped?

[jjack529]

I have a 2002 Volvo S60, 2.4 FWD Automatic Trans, with 120000 miles. I have had all scheduled maintained done at the Volvo dealerships, including my timing belt replaced early this year just before the recommended 105k. Last Monday I had to slam on my brakes to avoid an accident, I avoided having an accident but my car died, and would not restart. I had it towed to the Volvo dealership and they are telling me that the timing belt has slipped/jumped timing. Nothing appears broken, the belt is not broken, however the timing is now off, the engine will not hold compression so they believe the valves are bent and heads possibly damaged... needless to say $4000+ to fix, so not worth it.

Has anyone heard of this happening? It has only been 15,000 miles since the belt was replaced. Could they have messed something up when they replaced it earlier this year that has caused this to happen? In addition, they replaced the air conditioning compressor clutch in July, could they have messed something up then?

They told me they've never seen this before, it is just a very unlucky occurrence, the only possibility they could think of is that some road debris got up in the engine compartment, and slamming on my brakes dislodged it and it came between the timing belt and the cam, or something causing it to jump timing... is this feasible?

Thanks!

[007 HNP]

This is an interesting situation.

I you did not hit anything with the car just applying the brakes hard will not cause the belt to come off even it the anti-skid did not work at the time.

The fact that the belt is still on means that the individual parts of the system like the water pump and idler as well as the tensioner are all ok or the the belt would have come off.

The belt tensioner is spring loaded to apply tension to the belt so the only way the belt could come loose is if the crankshaft ran slower or backwards relative to the camshafts as the engine decelerated during the stop. There is a possibilty that this action could cause the belt to skip but the chances of it happening are extremely remote unless the belt tension was too low.

I can think of one thing that could cause the cranck shaft to slow down very fast and that would be transmission going into reverse gear while the car was moving forward.

The timing belt is completely covered by a plastic shroud, so the possibility of something coming loose under the hood or even road debris kicked up from underneath knocking the belt is also extremely remote.

If the timing has not been corrected, this condition alone could cuase the engine not to hold compression depending on what method was used to test the compression.

If the engnine timing has not been corrected, I would make sure I took a picture of the tensioner as it is and compare it to a properly installed belt and tensioner to confirm that the belt tension was set correctly or the bolt holding the tensioned has not come loose. Both of these conditions could occur a it the belt and tensioner not being properly installed.

Once the timnig is reset corrrectly if it has not already been done, confirm the condition of the engine.

Hope this helps