Anti-freeze Leak

[Mike Siner]

I'm with @scoflaw on this. That the overflow line (that usually has little to no pressure) ruptured seems to me to be caused by a very large/instantaneous increase in the cooling system pressure. That in combination with loss of power with black and white smoke would lead me to think head gasket as well.

I think I would get in touch with the local CAT mechanic and get a good diagnosis. The first order of business is to do no further harm. While not cheap, a new head gasket and resetting the head (I'm assuming that will need to be done), wont to too bad, as long as nothing else gets bent/broken.

I hope I am in the right place for this question. I have a 1992 Sea Ray 350 Express Bridge that I just put two rebuilt long blocks in mid-last year. The starboard side always steamed a little more than the port, but I am noticing an excessive amount and even had other boats stop me thinking my boat was on fire. I cleaned the sea strainer (not clogged at all) and cleaned the seacock, and am getting great water flow, I changed the impeller (the old one was in perfect shape) I checked the trans cooler and engine oil cooler both are clean. Under load, the starboard energy dash temp gauge matches the port engine's temp. I use a thermal gun, and the starboard risers run at 130 to 110 degrees, and the port risers are at 95 to 110 degrees. risers and exhaust manifolds were changed with engine rebuild. Any suggestions?

 

[mrsrobinson]

My previous inboard twin big block gas engine boat did this as well, I think you've done all the right checks and you're probably fine. The laser temperature gun to me is the best test, and I assume you compared the numbers to the other engine.

 

[Mike Siner]

My previous inboard twin big block gas engine boat did this as well, I think you've done all the right checks and you're probably fine. The laser temperature gun to me is the best test, and I assume you compared the numbers to the other engine.

I compare both engines' intake manifolds, transmission housings, risers, thermostat housing....etc everything except for the risers matches within a few degrees. The risers' tops are about 15 to 20 degrees different from the starboard to the port engine. But the steam is very thick. As I mention, I had other boats coming to my rescue because they thought I was on fire...