8V92 coolant loss

[finatic]

One of my 8V92's is loosing coolant. No apparent leaks. No water in the oil (thank god!). Leaking into raw water in heat exchanger and out the exhaust? Has anyone had this issue or any ideas?

[rustybucket]

if no leaks, no water in oil the likely suspect imo is the heat exchanger. I'd pull it and have it cleaned and tested.

[oscarvan]

Or it's finding its way past the sleeve seal(s) into the combustion chamber and going out the pipe not in the water but in the fumes?

[Dan Mapes]

Does the '92 series also suffer from injector tubes leaking AF into the oil? Over time small amounts get into the oil and boil out. It shows up in the oil analysis. A clean piston dome is an indication on a straight 6 like the 6-71.

[Hat52MY]

I would suspect the heat exchanger as a first option, given the oil is clean. You should be able to test in place if you have a Radiator Pressure test kit, by isolating the heat exchanger raw water & coolant side. If it fails the test, you should be able to take to a good radiator shop to see if it is repairable.

[Captain Ralph]

Does the '92 series also suffer from injector tubes leaking AF into the oil? Over time small amounts get into the oil and boil out. It shows up in the oil analysis. A clean piston dome is an indication on a straight 6 like the 6-71.

Hopefully there is a coolant recovery bottle. If you see bubbles or overflow, Injector tubes are the #1 suspect.

[HahnR]

Pull the hose on the air box drains and see if coolant runs out. If so, you can pull air box covers to see which cylinder is the culprit. If no coolant in the air box drains, I'd pull a raw water hose off the heat exchanger. Assuming you have the tank full with coolant, put something under the outlet and check for coolant after a short period. You may need to pressurize the cooling system with a tester, I wouldn't take it above 15 psi.

We had 2 cracked liners caused by faulty liner o-ring seals. Kept losing coolant, as long as we ran it, it vaporized the coolant. Never made any oil until it sat for a couple weeks. Like stated above though, an oil analysis will find it if it's making it's way into the cylinders

Hoping for the best for you...
Randy

[krush]

One of my 8V92's is loosing coolant. No apparent leaks.

How could you not see the coolant leaking out and collecting under the engine?

[jmooney]

I had a rapid coolant leak and the water shot outside of the outboard stringer and then went forward to a limber hole and then to the starboard bilge. No water was under the engine. I was flabbergasted for a while.