abones

Heads up guys, with the Extremely cold water temps in the Northern Great Lakes this year, there is a strong possibility that you can crack your heads/blocks and manifolds if you run them hard and heat em up then the t-stat opens long enough to get a gulp of some cold water. Seen it happen twice so far this year, both where Iron heads and both cracked between the valves. Beware!

BUP

iTrader: (9)

And do not forget if you have a lot of chicks around the Shrinkage factor that will take place. Better bring extra packin. anyways I thought it was funny.

All kidding aside just wanted to ask do you think any of these failures were related to improper winterizations beforehand. We see so people these days winterizing their own boats, jumping on youtube and so forth for the expert marine service training. .By springtime and the first couple of times out boating, guess what they have - something cracked internally or externally.

abones

Sure could be due to winterization, I was concerned enough about that that I started a thread late fall to address the subject. Now I wonder if others have had cracking in the somewhat warmer Midwest lakes, as opposed the Northern Great Lakes?

BUP

iTrader: (9)

Well I know some marine techs in Canada, I will ask them to see what they say plus I know one marine tech in Alaska. They will have seen / worked on a couple of hundred boats by now.

3pointstar

abones -- how can that happen? When a thermostat opens it's gradual - it's not all or nothing - therefore there wouldn't be a thermal shock -- I don't think the crack heads were the result of cooler water temps -- I suspect something else was at fault-- Maybe I'm wrong

3pointstar

abones

True on the gradual opening unless you run it hard as I stated then the stat will stay open wider and longer just enough to get that one little gulp needed to shock them before the stat closes, as it closes slowly also.
.

NevrThrottleBack

http://www.glerl.noaa.gov/res/glcfs/...t&type=N&hr=00

Northern Lake Michigan has seasonably cold water temps this year! 35 degree water temp is a big difference from the high 50 degree water temp last memorial weekend. Thanks Abones for bringing this to our attention.

abones

On an automotive use the temp differencial is normally much closer than that on a boat in cold water, a car will bypass back to the motor and thermo transfer backwards through the lower hose to help preheat the rad Gradually before the stat opens, in a boat the bypass water gets dumped and the working differencial is substancialy greater.I'm sure that normal operation might be fine but during a hard wot run all bets are off in my book.

BUP

iTrader: (9)

I have seen it happen as were the motor cooling system was on the weak side - the engine temp was highly elevated way above normal while running. Motor was shut down for x amount of time, the motor heat soaked during that time, the motor was restated - cold lake water - very hot heat soaked motor - especially the exhaust manifolds,

I seen it where it would cracked exhaust manifolds and a few heads. One example in the 90's the 3.0 / 4 banger Volvo Penta exhaust manifold all one piece would crack internally from this same scenario. It was also due to a thin wall casting in a few spots internally.

In the northern parts IMO If that's really happening because of lake temps I think this happens more so upon restart after heat soak of the motor especially if the motor had elevated high temps to begin with and your 35 degree water temps that is taking place..

A very small possible help to this might be to raise your engine hatch and leave your blower on when shutting down the motor and leaving it that way till after the engine restarted plus make sure your cooling your motor properly along with proper winterizations beforehand.

SB

iTrader: (1)

I don't know about this theory. Would like to here more from others. I've boated the day the ice has gone out many times, so haven't friends. No issues. I know, small sample.

Anyway - difference between 70*F and 35*F is 35*F. Combustion temps are 1300F+ and exhaust temps the same. See where I'm going. That 35*F really isn't much of a change in comparison.

What I do know:

Ice will break anything.

The typical -50F RV antifreeze isn't good at all. Full strength it still turns into Slurpee ice mush when a little below 0. Add some water that didn't fully drain and wham bam sorry mam you are cracked.

I see people buying that all the time here to winterize their boats. I'm not cool with that. If I had it and I saw our temp hit -20F like it did a few times this year I'd poop myself.