My Dad's V70 P3 has had the aux belt, a/c belt, tensioner & timing belt replaced fairly recently (Volvo parts). As he was parked up in a supermarket car park about a month ago, he started the vehicle after shopping as you do & heard a very loud bang - He turned the car off immediately. The RAC came & brought the vehicle to a Volvo specialist who confirmed that the water pump had packed in & the force of it de-railed the timing belt slightly & the timing cover was bent also. Luckily, it didn't do any damage to the engine or head! The timing belt was hanging on by a few teeth according to the mechanic & its a good job my Dad didn't attempt to drive the car home after the noise he heard, or it was game over really.
The water pump on inspection wasn't a genuine Volvo part - The bearing had seized & it basically fell apart under load. So another timing belt, a new timing belt cover & a genuine Volvo water pump was fitted. Its running fine now, thank goodness! When getting the belts etc replaced in the first instance before this happened, we were told that the genuine Volvo water pumps don't give much trouble & there's no need to change them. It turns out that was statement was true because it was an aftermarket/cheaper part that failed. Its a pity their belts aren't as strong, although Volvo probably don't manufacture them anyway come to think of it? Anyway, I thought I'd share that story with you
Have you gone ahead with the repair then? That cover is expensive like you say, but its worth its weight in gold so to speak. So this cover protects the aux belts getting chewed up with the timing? Will it do the same for the timing belt de-railing & possibly getting caught with the aux belts, or does the timing cover offer protection in that instance?