XC70 2.5T Killed by Water Pump Pulley Bearing

[mlc611]

NOTE: I edited the title now that I've done some more investigation. Please chime in if you doubt my conclusion. I'd love to hear that I'm wrong.


Hey guys,

My '06 XC70 was on the highway last night when I felt/heard a soft thud. Thinking a tire might have had a problem, I pulled across traffic and off of the highway. By then, the engine was not running and would not restart.

I looked at the timing belt, and I thought it was visibly off. I pulled at it and it was loose / out of position. Today, I went to pull the timing belt out all the way and was surprised that it wouldn't come out. So I took off the timing belt cover and was surprised to find the timing belt in tact. It was, however, not looped around the water pump pulley.

So to all appearances, it seems like the belt slipped out of place and killed the engine. But I guess there's some chance that by tugging at the timing belt, I popped it off, and there is actually a different reason that the engine died. Is it possible to make a timing belt come out of place this way just by tugging at the exposed part of the belt between the two VVT pulley? I wouldn't think that hand force would be enough to pop the timing belt off without pressing the tensioner.

Anything else I can quickly check, keeping in mind that there's no attached timing belt right now? The fuel rail has pressure, and that's about the limit of my diagnostic know-how.

Thanks!

[mlc611]

Some more info:

1. There's a Metal Volvo dealership decal saying that belt was replaced at 100k on September of 2011. Car currently has 176k.
2. I think I had power for the first 10 seconds or so after hearing the thud. By the time I was in the rightmost lane, I watched the tac slowly fall from 1k to 0 and pressing the accelerator had no effect.

Are timing belts known to just fall off? Could there be another issue going on here?

[mlc611]

And more info:

1. I worked the timing belt around enough to inspect all of its teeth. They're all in tact.
2. I go to spin the water pump pulley by hand. It feels rough. Within a turn or two, it binds up and seizes. I can free it, and it binds up in the other direction within a turn or two. I free it again. There's a degree or so of wobble in its axle.

So now I'm 90% sure that the water pump bearing seized and threw the timing belt off. I am assuming that the water pump pulley is supposed to turn smoothly by hand.

Sounds like this has happened before:

Failed water pump causes timing belt failure

So a $30 water pump bearing can fail and kill an entire Volvo. License plates are back on the Lexus. Anyone want a mint XC70 with a blown engine? I know the answer, but is there any chance that the engine escaped damage?

[XC70Rider]

Driving at highway speed I assume your valves are bent and the engine cannot restart. A water pump failed and bent the valves on another member here last fall. He had the head machined and fixed the valves himself with a compressor he baught on amazon.

I've read the water pumps usually last to 200k so yours went a little early. My 2007 XC70 is approaching 127k and I just threw on a new water pump when doing the timing belt, tensioner, and idler.

[SuperHerman]

Well you both are in MA, maybe close enough where if XC70Rider still has the old water pump he can give it to OP.

Easist way to tell if the valves are bent is to put on a water pump and retime the engine. Then do a leak down test or compression test to see if you suffered damage. Chances are very high that you did, but I had a Subaru that had an idler pulley fail and it managed to survive. Low chance, but if you can put on a used water pump and time it you will have your answer.

If you are going to keep the car, assuming worse case scenario that you need a head rebuild, you will have to buy a new water pump and timing belt kit regardless.

All other ways to check for bent valves, other than dropping in a scope, require you to pull many parts - of course all these parts have to come off to do the head. But, in theory, with a bore scope and a leak down tester - you could put the engine at its timing mark, pull off the timing belt, and rotate the cams watching for them to all be closed on the cylinder you will test. Repeat for each cylinder. Based on what I read on the 2.5T, the valves will not hit the pistons at the timing mark.

Pulling the head is not that difficult, but it is not easy. Just throwing out ideas that are fairly easy.

[abscate]

I've got a brand new Aisan pump I'll loan to test, if you keep just replace in kind.

I drive from mile 0 to 130 on the Pike every Tuesday so can't be far away.

[crlande]

My Subarus were non-interference engines and had two timing belts. If they broke no biggie, Volvo not so much.

[June]

Some more info:

1. There's a Metal Volvo dealership decal saying that belt was replaced at 100k on September of 2011. Car currently has 176k.
2. I think I had power for the first 10 seconds or so after hearing the thud. By the time I was in the rightmost lane, I watched the tac slowly fall from 1k to 0 and pressing the accelerator had no effect.

Are timing belts known to just fall off? Could there be another issue going on here?

Unfortunately Volvo has the waterpump scheduled for replacement every other belt change. Most on here agree with this. Also it is mostly agreed not to use anything but a Volvo or Asian brand pump. Both are supposed to be the same. I personally had the pump and thermostat changed with both timing belt changes on my 2004 to my mechanic's dismay. As he agrees with the general consensus on this subject.

The 2007 C70 I bought for my daughter last year also had a Volvo sticker on the timing cover and only the rubber belt apparently was changed nothing else. Last week it was apart for a blown head gasket and the mechanic noticed so I had to eat a timing belt job and yes a water pump and thermostat... unless a trusted mechanic has installed the timing belt its a good idea to just change it again to be sure. That sticker comes in every genuine Volvo belt kit. It is no guarantee the dealer actually changed it fyi.

I hope your engine isn't seriously damaged! June

[oragex]

First, sorry for the loss. You mention the engine would not restart after pulling over, this is pretty much a case of slipped belt/bent valves scenario

It is surprising for an original water pump to fail at 170k miles. In the link with another video you posted, the owner mentioned the pump was aftermarket with 45k on it - which is quite a long life for an inexpensive aftermarket pump. Usually these can fail as soon as 20K miles. During the past 5 years I'm reading on Volvo forums, there were a few situations with failed pumps - it turns out all of them were aftermarket units. You mention the Volvo timing belt sticker, and we don't know if the pump was replaced at the moment, as most dealers don't touch the pump until 200k miles. Would it be possible a previous owner went replacing the pump somewhere between the 100k miles belt change and the day you bought the car ? I am interested to find out if yours is the original pump or at least an Aisin brand one. If you can use a mirror to look at it from the side, this is where it would have either Volvo or Aisin stamped (click the small pics) https://www.fcpeuro.com/products/volvo- ... -engines-1

As for the timing belt, it is very hard to push off the cam gears by hand when the tensioner is set (it can be done, but it takes several pushes with pressure to slide it sideways).

[cn90]

...The 2007 C70 I bought for my daughter last year also had a Volvo sticker on the timing cover and only the rubber belt apparently was changed nothing else. Last week it was apart for a blown head gasket and the mechanic noticed so I had to eat a timing belt job and yes a water pump and thermostat...

My 2004 V70 with 108K miles: there is a "Volvo TB Sticker" at 90K.
The local dealer told me they did the "Timing Belt" at 90K.

Does anyone know when dealer does the TB job, is it just the TB or all 3 items (TB and 2 pulleys)?