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Kirk Rieber

Engine Rust

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Kirk Rieber

So, my engine with 971 hours in my 2008 VLX was destroyed this winter due to a failed winterization (DIY, but the first issue I've had in 15 years of boat ownership).  I took the old engine back from the dealer to tear it down and get a good look at the damage.  I was impressed with how thoroughly ruined it was.  Both heads have large chunks of metals gone and the block has cracks all over the valley where the intake manifold sits.

28747166147_4bc4e1e78c_c.jpgVLX by kdrieber 

42730990035_4f0eff7fec_c.jpgVlx Engine by kdrieber

During the teardown, I pulled all the casting plugs and the amount of rust that came out really surprised me (7 " pair of pliers for scale).

 29765017048_da9895a0fa_c.jpgVLX by kdrieber

This (at least is seems to me) is a lot degradation to the block.  I assume that this can restrict flow of coolant throughout the engine and also weakens the structure of the block itself.  My question is, is there anyway to combat this on a fresh water cooled engine?

 

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formulaben

I'm sure there this will be debatable but I circulate RV antifreeze through the engine for each winterization.  It is supposed to help with corrosion...who knows, but it certainly helps me sleep better at night. 

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WABOBO

I've been worried about this for a while. Every spring when I drain the block of RV antifreeze, it comes out a brown/grey colour with flakes of rust in it. I'm guessing I'm not draining all of the water out properly. I've tried buying extra antifreeze for filling and draining, before filling again with fresh antifreeze for storage, but it doesn't help much. ¯\_(ツ)_/¯

Curious why aluminum blocks aren't used?

Edited by WABOBO

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oldjeep
34 minutes ago, Kirk Rieber said:

So, my engine with 971 hours in my 2008 VLX was destroyed this winter due to a failed winterization (DIY, but the first issue I've had in 15 years of boat ownership).  I took the old engine back from the dealer to tear it down and get a good look at the damage.  I was impressed with how thoroughly ruined it was.  Both heads have large chunks of metals gone and the block has cracks all over the valley where the intake manifold sits.

28747166147_4bc4e1e78c_c.jpgVLX by kdrieber 

42730990035_4f0eff7fec_c.jpgVlx Engine by kdrieber

During the teardown, I pulled all the casting plugs and the amount of rust that came out really surprised me (7 " pair of pliers for scale).

 29765017048_da9895a0fa_c.jpgVLX by kdrieber

This (at least is seems to me) is a lot degradation to the block.  I assume that this can restrict flow of coolant throughout the engine and also weakens the structure of the block itself.  My question is, is there anyway to combat this on a fresh water cooled engine?

 

That stuff is why you stick a screw driver into the block drains after you pull them.  I fill with a marine antifreeze to protect against corrosion - no idea if it does any good.  I've had bits of shale and sand come out those block drains in the past.

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minnmarker

I flush the whole cooling system with -75 (polypropylene glycol) RV antifreeze every fall after I have drained all the water - just in case there is some water hiding in the corners.

I started doing this on all the boats after an outboard got freeze damage due to "a mushroom shaped plug that, when not in exactly the right position, prevents complete draining sometimes."

Still make sure that the block drains are clear.

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justgary

I converted my engine to half closed cooling when I bought it a few years ago.  I got plenty of rust out when I flushed the block, but I was surprised how much more I got by putting a piece of panty hose in the thermostat hose (as a fine screen).

Doing that came as a recommendation from the company that made the heat exchanger so the rust wouldn't immediately block the exchanger flow.  The toe of the screen was full of rust when I removed it after about five hours of running (with salt away added to the water).  I flushed again and added antifreeze after that. 

Anyway, it's a reasonable idea to flush your block occasionally, and maybe even add a panty hose screen to the j-hose to catch chunks while you run the engine for a while in the driveway. 

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MadMan
7 hours ago, Kirk Rieber said:

 

 29765017048_da9895a0fa_c.jpg

 

This is the reason I would never rebuild a marine engine, I'd start with a donor block/heads from a car or truck.

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MadMan
7 hours ago, Kirk Rieber said:

 

28747166147_4bc4e1e78c_c.jpg

This is where they always bust, where the water jacket is the largest.  More water = more expansion = busted block.

 

 

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