winterized, but exhaust manifold still cracked!

[94OMC]

I guess I'm just venting here, but I'm also curious what could have gone wrong.

I've been winterizing the boat since I've owned it (8 years), this is the first time with a problem.

I drain the block, manifolds, poke around in the manifold hole to make sure it's clear, disconnect the water hoses at the water pump & thermostat housing, then reconnect everything and pour the pink RV antifreeze in from the top water hose until she's full. Maybe this Michigan winter got too cold for the RV antifreeze, or maybe I had some trapped water....but either way my port side manifold has a nice big crack on top now. Pink antifreeze started shooting out the crack as soon as the engine was running.

It got too late last night and I didn't check out the rest of the engine, but I know I have at least a manifold to replace.

The boat is a '94 - been in Michigan fresh water all it's life. Do you think I might as well bite the bullet and replace both starboard and port side manifolds? Do the risers have a limited lifespan and need replacing as well since I'm in there already?

No boating for me this weekend

 

[alldodge]

I guess I'm just venting here, but I'm also curious what could have gone wrong.

I've been winterizing the boat since I've owned it (8 years), this is the first time with a problem.

I drain the block, manifolds, poke around in the manifold hole to make sure it's clear, disconnect the water hoses at the water pump & thermostat housing, then reconnect everything and pour the pink RV antifreeze in from the top water hose until she's full. Maybe this Michigan winter got too cold for the RV antifreeze, or maybe I had some trapped water....but either way my port side manifold has a nice big crack on top now. Pink antifreeze started shooting out the crack as soon as the engine was running.

It got too late last night and I didn't check out the rest of the engine, but I know I have at least a manifold to replace.

The boat is a '94 - been in Michigan fresh water all it's life. Do you think I might as well bite the bullet and replace both starboard and port side manifolds? Do the risers have a limited lifespan and need replacing as well since I'm in there already?

No boating for me this weekend

Man that's a bummer, sorry to here, hope there isn't any other issues. The issue with RV antifreeze is it's good for the temp listed provided it does get mixed with some water. Bondo's statement is always the best, "air don't freeze". Pull the manifold are see what it looks like, then decide if you need to replace both. If your boat sits in the water during the season, well maybe it would be good to replace both. If it sits on the trailer maybe not, a close inspection should help decide. If in doubt throw it out

 

[Lou C]

I've used -100 for that reason, no worries as it stays liquid to as low as -50 or so....
I've tested -60 and -50 in the freezer and they have gotten firm but not expanded (this is at zero)....
I am one of the few advocates of back-filling with -100 after manual draining because I can clearly see the results, there is less rust in my engine or manifolds than if I had not done so. I can see this from comparing the original thermostat housing with the one I installed 10 years ago, when I started back filling with AF. That one has no flaking rust at all, the original one big flaking rust particles.
Its common for raw water cooled engines in salt water to have chronic overheating because of rust clogged cooling passages, I don't have this problem. The engine's 26 years old, used in salt at least half that time, but runs right at 160-165...