Just draining block is not enough

[shaw520]

Helped a bud with his boat last week,...92' Mercruiser 5.0, raw water cooled. Owner said he was getting water in the oil,.. so after some more diagnosis I determined water only in the #5 cylinder,... my first thoughts were a head gasket. So I removed that head, but the gasket had no visible signs of compromises,.. but obvious signs of water intrusion on the head/valve area. Cylinder wall looked fine, no obvious cracks on the exterior of the head,..so I took the head to a local machine shop for magna fluxing. Magnu fluxing showed no obvious crack but when he pressure tested the water jackets there was a very pronounced leak into the #5 exhaust runner. So we got a new head and gasket but as I went to install the new head I was using a pick to insure all the water passages going into the block were open, and sure enough (4) of the water passages on the lower side of the head (either side of cyl 5) were jammed clogged,... I asked him his winterizing procedure and he claims he removes the outdrive and then just drains everything....but doesnt ad anti freeze. Now I know this subject has been beat to death, but it is my absolute opinion that the reason this head cracked was due to the water remaining in the head and not allowed to drain due to the rust/flake built up in those (4) lower water jackets. Hence the reason I have ALWAYS added anti freeze to all hoses and thermostat housing AFTER draining all the water out.

 

[achris]

No his engine didn't crack due to not adding AF. It cracked because he didn't let ALL the water out of the engine. And even if you're an AF adder, that won't ensure the engine won't freeze. The only way is to ENSURE all of the water is out is to open the plugs on the engine and the manifolds and probe them. You must also remove the big hose off the water pump and drain that, and drain the power steering cooler too.

After all the water is out, by all means pour money into the engine (AF) and let it sit for winter.

But adding AF is not a guarantee against freezing. You must do the drain first. Adding AF after that is optional (And unnecessary)

 

[Rick Stephens]

I just finished winterizing 10 minutes ago a motor that was new 2 years ago. I didn't think the drain holes would show a need to be probed already. I was wrong. One side block drain was nearly plugged solid. Came out easy enough. Like Chris, no way I am adding anti-freeze. I get my motor up to temperature, shutdown and start pulling drains. I end with the water pump hose and then pull the outdrive. Motor then steams for a while. Will have temps in the twenties starting tomorrow night. There ain't nothing there to freeze.

That said, if enough scale is built up to block heads, they are toast whether you add antifreeze or not. No way a quick anti-freeze swap is going to replace all the plain old freezable water stuck behind those blocked passageways.

Rick

 

[Bondo]

That said, if enough scale is built up to block heads, they are toast whether you add antifreeze or not. No way a quick anti-freeze swap is going to replace all the plain old freezable water stuck behind those blocked passageways.

Ayuh,..... Ditto to the posts by Chris, 'n Rick,.....

There's more to drainin' the motor, than just pullin' the drain plugs,.....

We boat in water fulla sand, 'n other junk,.....
Most of it collects in the bottom of the block, right at the drain plugs,.....

 

[shaw520]

Well I respectfully disagree,... scale is scale and depending upon which area of the country you are in. In this case there is NO WAY you can probe these area of the water jackets,... they are high on the block,.. where the block meets the head,...in fact for some unknow reason, the haed gaskets have a restrictive hole that is MUCH smaller than the actual water jacket going form the head to the block,... nearly every early 90's RWC heads Ive taken off were clogged at this point and theres no way to probe that area,... So the little bit of water will remain in the head

 

[shaw520]

Most of it collects in the bottom of the block, right at the drain plugs,.....

This is true,... and it also collects where the head meets the block because of the reduced restriction holes in the head gaskets.

 

[shaw520]

Here's an interesting articular on the subject

http://www.felpro.com/technical/tecblogs/head-gasket-coolant-holes.html

But even more so with a raw water system,... so much debris flying through these passages

 

[shaw520]

Heres another example of what Im referring to.

http://www.felpro-only.com/break_room_forum/printthread.php?tid=1261

 

[Bt Doctur]

a need to be probed already. I was wrong. One side block drain was nearly plugged solid.

That is the reason I remove the Quick Crack drain system. Everytine I removed the quick connects at the block they were plugged up.So now my customers get regular drain plugs in the block and manifolds

 

[shaw520]

I knew Id meet some resistance on this subject,... but in my 40 yrs of boating ive learned to drain, probe,.blow with compressed air, and then finally,... top off block with AF.... never had a crack,.... and Im not about to change that

 

[shaw520]

When you probe the drain hole you are getting to (1) water jacket at best,... there are (7) more on each side of the block. The scale in this 92' (fresh water boat) was nearly half way up the block in every jacket I probed,..(probed from the top with the head of),... I used a magnet to remove what I could,.. but I recommended some serious flushing to the guy after reassembling.

 

[Scott06]

No resistance... no dummies on this forum... if you have a system you like and are comfortable with use it. Ask two guys you can get three answers, none of them wrong. Certainly 40 years, run what you brung and your friend is lucky that u can diagnosis and fix for him.

If the ports were clogged could the crack be from lack of lack of water flow while running vs freeze crack? More on old inline chevys seen them get hot and crack in exhaust port. If sediment clogged I'd think this may be due to localized overheat vs freeze damage but could be wrong. Just a thought.

 

[shaw520]

I reckon that is possible as well,...although he stated that the motor never ran over 160 degrees,... I suppose local hot spots may have been the cause of the crack.

 

[Rick Stephens]

Seems we need a flush method for scale and sand buildup.

 

[Scott06]

You'd never see it if localized to one exhaust port, thermostat would still be ok, like when the head cracked on my grandfathers 250/150 hp straight six years ago... bad water pump air pocket in back of head, temp warm but ok.

Learned that ten degree diff in temp was indicative of water pump impeller wear and lower flow, even though not 'hot' on temp gauge. Grandpa paid the $1800 repair bill, promptly gave my brother and I the boat and said if something broke he didn't know us...teach me to work on a boat I can waste a life time...

 

[Scott Danforth]

Seems we need a flush method for scale and sand buildup.

A flush with oxalic acid works. Drain, flush, let sit, run, repeat. However salt water boats will flake pretty good until the heads rust thru

 

[Rick Stephens]

A flush with oxalic acid works. Drain, flush, let sit, run, repeat. However salt water boats will flake pretty good until the heads rust thru

Thanks for the tip. I gotta try it. For me, it's all fresh water. My one trip to salt was a bad wind in Monterrey and cross seas too scary for a 17 foot soap bubble. I did a wash out with salt killer every day I tried to go out. Probably no more salt in my boat's future. I know after today that scale and sand build up pretty fast even in fresh water.

 

[shaw520]

Ive seen "salt away's" direct injection system,.. looks interesting,... Im looking to install something similar to this on twins.

https://www.youtube.com/watch?v=D05sirp5giY

So Im thinking about using the hose bib proportion valve temporarily mounted inline on the raw water feed line and run for 10min or so.

 

[shaw520]

I know after today that scale and sand build up pretty fast even in fresh water.

Our boats have all been fresh water,...and the scale is plentiful,... maybe not as corrosive as salt water, but plenty of rust scaling no doubt.
The boat next to me at the marina is a 46 Four Winns with twin Volva Penta Pods,...installed on it is a Nuetra-Salt system that automatically injects the solution for 30 seconds on shutdown (just prior)

 

[Scott Danforth]

I use salt-away to flush the motor (I have a half system) and to rinse off the trailer. I then follow with a fresh water rinse. Been doing it for years.

only way I could keep a painted steel tube trailer alive as long as I did down here.

the volvo penta neutra-salt system is a good one too. similar chemical to the salt-away. same concept.