7.4 454 Inboards...Unwinterize issue ??

[rothfm]

I bit nervous with something I saw today, when pulling off my brothers twin 7.4 mani's and risers for replacement. I Cant really explain this. These are INBOARDS.

Blocks are fresh cooled, with raw in Mani's and Risers( 1/2 system). Removing each manifold, I first took the hose off to drain any liquid--I expected to see a fair amount of PINK come out.....For the most part very little if nothing came out (maybe a tiny bit of rusty looking water). The last of 4 manifolds, I was surprised to see a cup, maybe two, of what appeared to be clear water come out of the hose?? CONCERDNING. It did have a bit of odor like the Pink, but was mostly clear with some rusty cloudiness to it.

I personally winterized each motor (like I have done on his past MC's with no issues), by taking the main Raw supply hose off at the hull seacock, and allowing the motor to suck in 6 gallons of PINK. At the time, each motor clearly had a good amount of solid pink exiting the exhausts.

I dont understand why those mani's werent filled with pink....and what could possible be the reason for one mani hose to have some water in it?? Seeing this, is there any chance any was in the block, chancing cracking? I now sometimes its hard to tell if it wasnt "pink-ish" down there in the bilge, semi-light conditions. But it really looked like mostly water.

Will be doing some bilge cleaning, hose replacements, and block cleaning---before installing the new equipment.

Thought i would come right home and post for some needed input, so I can maybe sleep tonight!!

 

[alldodge]

To start with Bondo's phrase, air don't freeze

If (the big IF) you drained everything (block, manifolds, water pump, coolers) prior to letting the motor suck the RV stuff in, then your good.

But IF you just let the motor suck the RV stuff in without draining prior, then there may be a problem

 

[rothfm]

If I understand the MC cooling diagrams for this motor correctly...There is only recirculating Glycol Antifreeze in this cloosed loop Block. Raw Seawater water comes in, thru external components( oil cooler, trans cooler, fuel cooler, into the exchanger, then out to the Mani, and ejected out the Riser.

So, even if there was a problem with freezing, wouldn't it be external like a hose, mani/riser, oil cooler etc....meaning isolated to the "external-to-the-block" raw water path only? It hasn't been run yet, so theoretically if there were a compromise on the Raw side, the Block should still be intact with Glycol Coolant

Yes/No?

 

[alldodge]

Yes, your correct, the block should be fine, my bad
So if the manifolds/risers/HE were drained then refilled with RV then no issues. If they were not drained first, and if there was some build up on the hoses, HE, thermostat housing the water pump may not pump equal RV stuff everywhere. In fact the water pump even when new does not pump equal to both sides

 

[rothfm]

Gotcha, Thanks for this Alldodge. We will monitor closely those external systems and fluids closely at startup..if there were a compromise, should be isolated to one of those external portions.

Finally found the Water flow diagrams, those helped too.

Thanks