A relative is offering me one of the 740 sedans with the 16 valve engine. It's in very nice condition, but appears to have a fairly serious oil leak coming from behind the exhaust camshaft timing belt sprocket. I assume that the oil seal for that cam is shot, and needs to be replaced. I'm fairly experienced at working on cars, but have no previous Volvo experience. I've poked around on the internet, but have not found information on cam seal replacement specific to the B234F engines. I would appreciate it if someone could either point me to a site having such information, or else just briefly run down for me what needs to be done in order to get access to, and replace, the exhaust cam seal on one of these motors. (If possible, I would prefer that this not turn into a complete timing belt/balance belt replacement job, as the engine on this car is about halfway through the service interval.) Thanks very much.

I highly recommend Rob's advice with one addition: replace the oil pump bolt as well, a known failure item. See the 700/900 FAQ under the "features" button above for more help. There is a section devoted entirely to timing belt replacements on B234 engines.

Well, given this engine's rather poor track record with timing belt failures, and the root cause of the failures, I'd strongly recommend that you replace all the front engine seals, and the main timing belt at a minimum.

That would be the crank seal, intermediate shaft seal, and two cam seals. Plus the main timing belt which is only $100 or so.*

The reason for replacement is that oil attacks rubber. The rubber belt is guaranteed to be weakened already by the oil leak. A weakened belt on an engine with already weak timing belts is a bad thing. This oiled belt could fail well before its service interval. As opposed to the regular B230 belt which is rated 50K, and performs for 100K under most circumstances.

*Note I said "only" $100.... while much more expensive than a regular 8-valve belt, the price is only 1/20 of what it costs to have one of these engines rebuilt after a failure.... it's an interference engine, which means that a belt breaking causes the pistons to strike the intake valves, bending them and jamming them in their guides. Costs I have seen for these repairs run from $2000 to $2200. Avoid the failures at all costs.
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Rob Bareiss, New London CT ::: '86 244DL- 215K, 87 244DL- 230K, 88 744GLE- 198K, 91 244 180K

I would think the B234F cam seal replacement would be nearly identical to that of a B230 (the cam-blanks and gears are probably identical, just that there is 2 cams... And as for the oil pump pulley bolt, you want to change it, I was told that it was a M10x1.25 by someone, but mine ended up being a M10x1.50 and i don't remember how long.

As for doing a valve job on the engine, it's about $650 worth of parts... (all because of a $2.00 bolt!)

Actually, doing a timing belt change on a B234 (in my opinion) is simple... I like not having to remove the harmonic balancer.

Cliff Scott
89 DOHC740