2016 Volvo S60 - Alternator broke belt which then broke the head - Any help?

While costs certainly vary in different parts of The US, I am sure that you could find a qualified independent foreign car specialist to do the required work for far less than $9,400.

The biggest cost is the head assembly itself Volvo won’t send the old head out they guarantee the work for as long as I own the vehicle but insist on a $5k head assembly from the factory I am torn

That would seem to imply that you are relying on a Volvo dealership, which is sure to charge much higher prices than an indy foreign car specialist. There is really no good reason to take a 7 year old car to a dealership, as long as there are indy specialists in your area.


I’m having trouble understanding how the accessory belt snapping can damage the head. Are you sure you don’t mean the timing belt (if your car has one)?

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Looks like only the 3 liter engine has a timing chain. All others have a belt. All are interference engines. The belt has a 90K mile replacement interval but I’d bet there is a time component, too. 7 years seems a little short but I cannot imagine how a failed alternator would cause this.

But unless Volvo is paying for this, I’d be buying a rebuilt head and having the work done at an independent shop rather than the dealer. Should be cheaper than 9 thou.

The options are clear, fix it or sell it as a broken car for far less than the cost of repair.

I’m guessing that, on this engine, the water pump is driven by the serpentine belt, and that the engine overheated, thereby damaging the head. That’s the only scenario that I can come up with, but I don’t know if this was actually what happened.

I know it sounds incredible but the serpentine belt snapped when the alternator seized snapped and wrapped around the crank screwing up the timing this damaging the head trust me I am having a hard time believing a $450 part caused all this damage

Freak accident. I assume you would not feel any better if it was a $1 part :grinning: If this was mine, I would invest the small amount to have someone look in the bad cylinder with a borescope to see if the piston is damaged or it’s just a valve stuck open.

Then, if it looked like just the head, I would have someone like an independent shop do the work to R&R the head. I would not value a lifetime warranty so much on an older car to pay a premium for a new head, especially one with only 47k miles on it. Repair it and if it makes it past the 90 day warranty from the shop that fixes it, consider it good.


That sounds reasonable, I’m going to start looking for independent shops, where I am in South Jersey there are not many foreign car specialists nearby but I can have it towed anywhere

I am now looking at independent shops as every one advised thank you

Have you posted this on Volvo forums? They might have advice, both on the repair and on repair shops in your area.

I will thank you I’ve just been in shock that a seized pulley could do this much damage

It’s a known issue and I believe there is a preventative fix for it available. It’s important to stay on top of preventative car maintenance such as rust protection and things like this. Unfortunately most people at best do the factory specified maintenance and no more until something breaks.

The belt breaks and goes under the timing belt, removing the timing belt from its pulley. It is an interference engine.

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Just out of curiosity what maintenance can be performed to stop an alternator from seizing it’s a sealed unit isn’t it?


I remember something about improving the timing belt protector so that this doesn’t happen. Here is a more in depth explanation about the flaw in the timing belt protector. https://www.matthewsvolvosite.com/forums/viewtopic.php?t=80727&start=10#:~:text=The%20problem%20is%20when%20you%20have%20a%20little,engine.%20(often%20breaking%20it)%20(average%20cost%20from%20%243000-%244000)

It says that 2016 and up have an improved timing belt protector. I assume this protector can and should be put on an older engine during the next timing belt change.


Usually when the alternator is about to seize its bearing will start to make a loud noise. If you hear that noise, stop the engine and have the car towed to your shop. Beyond that, a shop could remove the belt and hand-rotate the alternator pulley proactively, say during a yearly inspection service. It should rotate freely, not binding, and not making any usual sounds.

Are you certain the problem was the alternator? Maybe the alternator was also damaged, and that is masking the actual cause. The most likely cause of the serp belt seizing seems like it would be a belt tensioner failure or an idler pulley malfunction. The belt tensioner really takes a beating, so that would be my first guess.

As you’ve sadly discovered, even a seemingly minor problem with a belt can cause major damage, especially if it occurs at high speed. Some engines are said to be free-running, and other interference, meaning if the timing belt breaks on a free-running design, the engine won’t be damaged. But that is overly optimistic. If the timing belt breaks at high speed, no way to predict how much damage will occur, free-running or interference engine design.

Me, I’d be inclined to keep the car on the road, and let a good, well recommended, Volvo-experienced independent mechanic propose how to do it.

This is actually not true. If a particular engine is non-interference, then it remains non-interference regardless of driving speed, or engine (RPM) speed.

For example, when I did the head gasket on my 1995 Caravan with the 2.5L 4-cylinder engine, I noticed that any valve fully opened did not protrude past the bottom of the cylinder head, and I could place a dime on a straightedge, and the valve would barely touch it. Similarly, the pistons dish downward, and a quarter sitting on the piston crown would just barely reach the engine block deck. Therefore, the non-interference clearance on this engine is equal to the thickness of a dime and quarter together, which should prevent contact no matter how fast the engine is turning when the timing belt fails.

On the Volvo which is the subject of this thread, the engine is interference, even if the timing belt fails at low RPMs (though the damage may be minimal in that case). And yes, I have read about this problem online, including on this forum, where it has been discussed in the past. Apparently, on this engine, if the accesory belt fails, it somehow becomes lodged under the timing belt cover, causing the timing belt to fail as well, and resulting in engine damage. The manufacturer, of course, denies that a defect exists.

If I had a car with this type of problem, and I had to pull the engine to replace damaged pistons, etc, I would have the machine shop modify the engine to be non-interference. By measuring how far a valve protrudes past the bottom of the cylinder head, and adding additional clearance for thermal expansion, it should be possible to obtain a set of custom pistons and connecting rods which will prevent any possibility of valve-to-piston contact if the timing belt fails again. The machine shop which I use has a poster on display from a company which manufactures custom pistons and connecting rods for street and performance applications.

Previous discussion about this issue: 2012 Volvo S60 - Car stalled - serpentine belt broke

And I thought I was the only one. The car was well maintained, it was in the shop every 5k for oil and filter and checkup. Nothing was dry rotted and there was no way to know the alternator was going to go, it made noise like gravel for about 20 seconds before everything came to a halt at a traffic light. I was reaching to turn the car off and I wasn’t fast enough…

I wonder if a large fender washer would fit over the timing belt cover. It would be bonded to the cover somehow. The crank shaft would go through it with a tight fit, preventing rubber fragments from a chewed up belt from getting inside the timing belt compartment.

It is frustrating to try and do everything correctly only to discover that more was needed but you just didn’t know. There are lots of things like this in our modern world. Like the guy who followed the advertised 10,000 mile oil change interval with his Toyota and had the dealer do it, but they probably used cheap 5000 mile oil. His engine needed a rebuild at 200k miles. Some of these things are safety things, like the rear axle on the Ford Windstars from around 2003 that trap salt water and crack suddenly.