V8 Balance Shaft

[ggleavitt]

Risk is noted for engine SN less than 6833, can see this post from another site for some background- https://forums.swedespeed.com/showthrea ... ure-thread

[Cducasse]

Does anyone know if it is possible for a mechanic to inspect to see if the drain hole is there without having to disassemble the entire engine to look at it? If it is plugged up, maybe clean it out somehow? I'm so nervous this thing is going to fail.

[Cducasse]

Someone that knows where to look can see with a mirror. The plastic cover has to come off but the is not a big deal at all.

[Roger_850T]

Man, I wish I had seen this prior to purchasing my v8 2005 with 59k miles in July 2019. I do love the XC90 and hope engine 7001 doesn’t suffer this defect. Here’s to hoping. Great write up, at least I know if I hear an engine noise, get it towed immediately

Cducasse,

Don't regret it. It sounds like you found a nice low-mileage vehicle that most of us would be jealous of. Enjoy it!

Information is your ally. Every vehicle has it's Achilles heel, and now you know this one. What I think you should take away: Be VERY aware of fluids getting down into the "V". Don't wash the engine, ever. I suspect I may have caused mine when I changed the fuel pressure sensor about 2 months before. In which case it was gasoline, not water, that got down in there, but both are bad. Be aware of ANY fluids in the vicinity of the back of the engine, and take significant precautions to avoid letting it drain down there.

Enjoy your V8! I just dropped $1k today on tires and suspension work. But it drives nicely again, and tires are a wear item. And I confess I *do* like the sound and the feel of the V8 when I step on it! Expect you'll need to re-seal the valve covers and timing cover somewhere along the way, (130-150k miles seems normal, but I don't know if that's a calendar issue or a heat cycle issue, probably a combination of both.) Do it when your engine lets you know it's time (by leaking oil,) then know you're good for another 150k. Not a bad deal, really, as many other cars are already in the junkyard by then.

One last thought: If you end up getting to the re-seal time, (and have to pull the manifolds off anyway,) you can probably drill "the hole" that is the fix for this issue without having to pull the cylinder head. You have to do that to get the bearing and balance shaft out, but I bet, if I were doing it again, I bet I could drill the hole after only taking off the manifolds. At that point, you've applied "the fix", and you can sleep easy for the rest of the life of your Volvo.

Cheers!

Roger

[Roger_850T]

Does anyone know if it is possible for a mechanic to inspect to see if the drain hole is there without having to disassemble the entire engine to look at it? If it is plugged up, maybe clean it out somehow? I'm so nervous this thing is going to fail.

Maybe. Yes if the manifold is coming off for another reason, if it's a mechanic that knows the Volvo V8 and what to look for. But it's too subtle for an average mechanic that doesn't do Volvos all the time.

That said, it's not a random thing. There's a definite causation here. Put liquid in there next to the bearing, and you have to deal with the consequences. So, work very, very hard to never put liquids in there! Don't wash the engine, be very careful with other fluids around (coolant, gasoline,) and I expect you'll be just fine.

Roger

[ggleavitt]

Interestingly enough, someone on Swedespeed did a scope on his engine and in my saying it was not possible, I learned that indeed it is. Perfect chance to use the cheap $40 semi-rigid wifi scope that I bought on a whim.

20190901122456.jpg

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It's important to note that I thought the hole was there and plugged with debris, why I put the wire down.

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As I ran that wire (aluminum end was expose 3/8") all around, I made a point of catching as much of the bottom as I could. At one point the wire is resting against the edge so that I could keep things stable to get get a photo.

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The shiny marks are aluminum, there is no hole.

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My 08 (0748) Sport V8 SN 32604 V8 (PN 6906091) has no weep hole. It has a casting impression that would like have been for a hole but a hole was never drilled. This is my original engine.

See image for general orientation of the CB valley

CB Valley Orientation B8444S.JPG

Adding re-work diagram for reference

CB Shaft Rework Snapshot.JPG

edit 090319- add additional images

[Roger_850T]

Very interesting. More interesting to note the incomplete drain hole. That would seem to be a problem... Thanks for sharing!

Roger

[bmdubya1198]

Hmm... that's a little unsettling. I'll have to give that a look when I tackle the timing cover gasket job I keep putting off.
Thanks for posting those pics!

[tjmotter]

Has Volvo ever published a replacement interval for these parts? I have an '08 coming apart to replace the valve cover gaskets and it has over 160K on it. If there is a recommended replacement interval this would be a good time to do it but I would hate to pull a head off for no reason.

thx
Todd

[Roger_850T]

Has Volvo ever published a replacement interval for these parts? I have an '08 coming apart to replace the valve cover gaskets and it has over 160K on it. If there is a recommended replacement interval this would be a good time to do it but I would hate to pull a head off for no reason.

I've never seen a published replacement interval, it's supposed to never need replacing. And I would have to say, there is really no load on the bearing, so as long as it stays sealed and lubricated, it should not need replacing. The front bearing with the timing chain gear has more load, but also a lot more lubrication as it's bathed in the engine oil. Thus, replacement would really be on condition.

With that said, if you take off the intake manifold (to do the valve cover gaskets,) you should definitely inspect the outside of the bearing and verify that your hole is there. You can probably do it with just a good light; an inexpensive borescope (like my $50 USB scope) would help. That way you can verify the condition, and let that inform whether you go any further or not.

Roger