05 xc 90 v8

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what is c/s bearing fail

[RedGeminiPA]

My guess would be camshaft bearing failure. Maybe someone else knows exactly what it means.

The reason for that guess is Yamaha V8 engines have always been prone to camshaft failures of some sort, dating back to the Taurus SHO V8. I've read of some '05 XC90 V8 camshaft failures.

[hoonk]

The counterbalance shaft bearing fails on early engine # cars - it's in the v of the engine and somehow water damages it. It can destroy the engine if it fails.

check this thread
http://www.volvoxc.com/forums/showth...shaft-failures

[05XC90V8]

My guess would be camshaft bearing failure. Maybe someone else knows exactly what it means.

The reason for that guess is Yamaha V8 engines have always been prone to camshaft failures of some sort, dating back to the Taurus SHO V8. I've read of some '05 XC90 V8 camshaft failures.

Yes and no. It wasn't exactly Yamaha's fault. In the SHO V8, Yamaha wanted to bolt the sprockets to the camshafts, but Ford thought it was a better idea to press them onto the end of the cams. Unfortunately, they could loosen up over time. Thanks Ford. The story goes in the XC90, Yamaha had the V8 engineered and built without a counterbalance shaft, but Ford (who owned Volvo at the time) said, well this wont work in this configuration because we need room for the crossmembers, supports, etc. So, Yamaha said the only way that they could do it without going back to the complete drawing board and having it cost a bunch of money, is to offset the cylinders the width of half-a-cylinder and install a CB shaft. (The orginal SHO Yamaha V8 was also a 60-degree engine, with no CB shaft.)

Yamaha builds incredibly reliable motors. It's only when Ford gets involved do things not go well. Yamaha didn't really have a choice - Ford/Volvo was the customer, they were just the suppier.

[cattlecar]

60 degree configuration is owed to the original engine and all the expensive tooling being for the original SHO V6 where 60 degrees is the ideal bank offset. There are some significant differences between the 3.4 Ford V8 Yamaha and the Volvo 4.4 version. Bore centers and other primary dimensions are the same so the same equipment could make the 4.4 version. Quad CVVT and balance shaft are some of the changes. Ford unit used belt drive off one of the cams on front head to turn water pump. Volvo version has water pump moved under forward block and serpentine belt driven.
60 degree V8 was great for fit into XC90 engine bay. 90 degree DOHC V8s are WIDE due to cyliner head width. Even the ones with primary chain inboard and a secondary chain or gears driving exhaust cam still have a much wider finished dimension.
There is a drain hole on the 2006 and later engines to allow water to drain into an existing hollow cavity in back of block. There is a coolant crossover cast as part of block that acts to dam up rear of the block. The front of block is effectively dammed up by the timing chain case. They put a drain in front of the rear balance shaft bearing but faild to drill a hole behind that bearing but in front of the coolant crossover dam. Water from cleaning engine will puddle there. Once the water sits it gets into the sealed bearing for rear of balance shaft. Casual water that falls there driving in rainy weather would evaporate from engine heat and would not even get to that spot usually since it is fairly well covered. The drain can be dded but the access is poor and drilling depth is critical. IF the hole is drilled too deep you pass through the intended cavity and drill into top of crankcase above crankshaft.
Replacing the failed bearing requires removing timing chain cover and one cylinder head. The heads are over the bolts and edges of bearing retainer cap.

Other than this balance shaft bearing fail on 2005s these engines have been very good.
The serpentine belt fixed idlers can fail (like the equivalent part on the many other engines using these) and their location on timing cover makes a bad failure subject to damaging timing chain cover. they make loud noises for a long time before this happens. Ignoring the noise is the cause of the serious failures.