Volvo Penta 5.7GS ; how do I test risers?

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parttimeboater

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I have a Volvo Penta 5.7 GS engine (built in 1996). Making a long story short, this past winter I neglected to winterize my engine and am now getting water in the oil (1.5 quarts after running only 30 minutes) twice and engine hydrolocked once then wouldn't start. I've removed the engine and it is now being rebuilt (found bent piston arm) and currently being magnafluxed (spelling) to check for cracks in block. I'm not convinced this is the only leak or want to eliminate the possibility of multiple cracks in different components. I've read other great posts on how to test the exhaust manifolds with acetone and I'll be doing that tomorrow. I'm also taking the precautionary action of replacing the flapper(s) in the exhaust 'y' connector and all gaskets in the water cooling path(s). I couldn't find any posts on how to test the risers. Does anyone have a suggestion on how to test the risers? Also any suggestions on how to test the intake manifold? Am I missing any other leak potentials? I'd rather be proactive instead of having to re-repair the engine.
 
45Auto

45Auto

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Re: Volvo Penta 5.7GS ; how do I test risers?

I've never seen a practical way to check exhaust manifolds or risers to see how "good" they are. A pressure test will tell you whether they're leaking at the moment they're tested, but won't tell you about the thin spot that's almost rusted through and will start leaking into your new motor in a couple of weeks.

If your manifolds and risers are original, then they're 14 years old. Sounds like you're dumping a good bit of money into the motor, hopefully the rest of the boat is also in good shape. Since you're having the engine rebuilt, I would probably spend the extra $500-$600 for a new set of manifolds and risers to go with it. Or you can just take your chances, how lucky do you feel? :)
 
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parttimeboater

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Re: Volvo Penta 5.7GS ; how do I test risers?

I plan on keeping the boat for 10+ years and it is in great shape. It has only been used on lakes and never in salt water. I'm now facing the "pay now/pay later" on the expenses, but between the risers and manifolds, I'm looking at about $1,100 (not to mention all the expense of the engine rebuild). Neither the risers and exhaust mainfolds look like they are rusting out. There is a posting about using acetone and filling up the liquid compartment of the manifold then waiting 20-30 minutes to see if it leaks. I might perform this test and see what results I get then decide if spending the extra $600 for the new manifolds on top of the new risers is worth the risk.

Bottom line: I won't forget to winterize the boat in the future.....expensive lesson learned :)
 
45Auto

45Auto

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Re: Volvo Penta 5.7GS ; how do I test risers?

If it's all fresh water, then you're "probably" OK on the manifolds and risers. The acetone test is similar to a pressure test in that it will show you the immediate condition of the manifolds/risers, but you still will have no indication if there is a thin spot waiting to rust through and leak into your new motor in a month or so.
 
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muscmkr

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Aug 30, 2010
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Re: Volvo Penta 5.7GS ; how do I test risers?

Just curious why acetone to test the manifolds? If you are just checking to see if they leak I would think water would be fine. :)
 
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