Anti-freeze Leak

drprunner

Member
Dec 31, 2008
75
SE Florida
Boat Info
1997 400 Sundancer
Engines
Caterpillar 3116 300hp
1997 400 Sundancer with 3116 Cats. Was driving the boat yesterday when I started loosing RPMs and speed. My passengers were yelling I had smoke coming out the back. I look and there is white and black smoke. Shut both engines down, open the engine hatch and white smoke is billowing out, looks like the whole engine room is on fire. After a few minutes the smoke clears out and I can see anti-freeze sprayed over both engines. On the port engine the small clear hose from the radiator tank to the reservoir has 2 large holes (pic1 & pic2) and the reservoir is full to the top (pic3) normally it is half full. I was able to limp home on the starboard engine with no other problems.

My question: could the blown hose have caused all of this by itself, or is there some other issue with the engine that could have caused the hose to blow out? Was the white smoke just steam from the anti-freeze hitting the hot engines (pic4)? I know the black smoke was caused by the drop in RPMs and unburned fuel coming out the exhaust?

Thanks for any help.

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To come out the overflow tank like that likely means an overheat condition actually caused the hose to blow, versus the other way around. The radiator cap will hold back ‘normal’ pressure, I think it’s around 15psi.

Did you notice how how the engine got before the smoke started?
 
Sounds like you blew a head gasket

+1 on this.

While it is normal to have expansion over flow and then when the engine cools it sucks it back in. When there is excessive boil over that is usually cause by a blown head gasket. Be careful in trying to restart that engine, if there is anti freeze in the cylinder then running the engine could bend a connecting rod and then your in for a rebuild of at least that cylinder if not the whole thing.
 
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.
 
The over flow line burst at the first restriction because the antifreeze was super heated and exiting so fast that the tygon tubing just burst when it lost it's rigidity from the heat.

In my opinion the injectors need to be pulled and a leak down test performed to see exactly what is going on. Pressure testing the cooling system may make it worse by injecting (more?) antifreeze into the cylinder(s). The cylinder leak down test or even a compression test after the engine has been turned over with a breaker bar insuring no antifreeze is in the cylinders. That will tell the condition of the cylinders and possibly where the leak is before the head is removed. Also a bore scope can be used with the injectors out to help determine the state of the engine. Just my experience with these things.
 
Mechanic figured it out! He took the injectors out and scoped the piston, no water/anti-freeze. Pressure tested the cooling system and nothing leaked into the cylinders, had a small leak in the hose connected to the thermostat housing. Put the engine back together and did a test ride. Discovered I had no water coming out the port engine, the impeller was shot! It was the bad impeller that caused all my problems! The bad impeller caused the engine to overheat and the pressure to rise in the cooling system. This caused the hose to burst, spraying anti-freeze on the starboard engine and into the air filter, causing the starboard engine to lose power and to blow white and black smoke. Mechanic said I was very lucky as any other scenario would have been expensive.

Thanks for the help, I love this forum!!!
 
First of all, congratulations, and how did you get a diesel mechanic out there so quickly. Second of all, that's the easier engine of the two to get access to so congrats, and go ahead and replace the starboard one it's going to fail eventually. And if your mechanic hasn't done so, start pulling things apart looking for impeller bits that will lodge and cause continued heating issues. I spent almost 4 months this past season chasing this down. Especially where the raw water goes into the HEX. That's where my bits lodged.

http://www.clubsearay.com/index.php...ting-running-hot-after-sucking-up-mud.110441/

Specifically, http://www.clubsearay.com/index.php...ter-sucking-up-mud.110441/page-7#post-1352034
 
Mechanic figured it out! He took the injectors out and scoped the piston, no water/anti-freeze. Pressure tested the cooling system and nothing leaked into the cylinders, had a small leak in the hose connected to the thermostat housing. Put the engine back together and did a test ride. Discovered I had no water coming out the port engine, the impeller was shot! It was the bad impeller that caused all my problems! The bad impeller caused the engine to overheat and the pressure to rise in the cooling system. This caused the hose to burst, spraying anti-freeze on the starboard engine and into the air filter, causing the starboard engine to lose power and to blow white and black smoke. Mechanic said I was very lucky as any other scenario would have been expensive.

Thanks for the help, I love this forum!!!

wow, that's the best possible outcome. A couple questions/observations:
  • I don't think the pressure caused the hose to leak, that overflow hose isn't designed to take that volume of overheated anitfreeze so instead your cooling system overcame the pressure cap on the overflow tank and fired hot antifeeze into the hose causing it to burst. Semantics really, the outcome is as you described: pressurized cooling system from the overheat
  • This part I'm not sure on since I haven't removed our injectors but -- it's possible the overhead and injection timing dimension need to be adjusted now that the injectors are re-installed. Do you know if the mechanic did that?
 
wow, that's the best possible outcome. A couple questions/observations:
  • I don't think the pressure caused the hose to leak, that overflow hose isn't designed to take that volume of overheated anitfreeze so instead your cooling system overcame the pressure cap on the overflow tank and fired hot antifeeze into the hose causing it to burst. Semantics really, the outcome is as you described: pressurized cooling system from the overheat
  • This part I'm not sure on since I haven't removed our injectors but -- it's possible the overhead and injection timing dimension need to be adjusted now that the injectors are re-installed. Do you know if the mechanic did that?
Yep, I think so. Something about new seat's are in order also? Still learning. @fwebster
 
  • "This part I'm not sure on since I haven't removed our injectors but -- it's possible the overhead and injection timing dimension need to be adjusted now that the injectors are re-installed. Do you know if the mechanic did that?"
This was not done, but I did notice the mechanic numbered each injector before taking them out to insure they went back in the same order. No new injector cups either. He said he's worked on hundreds of 3116/3126 over the years so I'm guessing I can trust his skill. Also, his company, MDSI, is a Caterpillar rep for SW Florida.
 
I'm jealous you were able to get a diesel mechanic to your boat so quick, takes months here, and even then they ghost you.
 
I'm jealous you were able to get a diesel mechanic to your boat so quick, takes months here, and even then they ghost you.
I called them Monday morning and they were at my boat Tuesday @ 9am. They had a big job scheduled nearby, but the boat is still on the east coast, so I got that spot. I'm having them change all the hoses, and with the new impellers, I should be good to go for awhile.
 
and with the new impellers, I should be good to go for awhile.
Maybe...

Make sure they check for impeller bits throughout your system, that's what got me even after I replaced my impellers when the engines overheated. They ran hot after the event. Read thru the post I referenced.
 

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