Burning engine coolant (Twin Cummins diesel)-gctid824646

[scampbell18]

I own a 2001 Bayliner 3988 which has two 330hp twin diesel Cummins. I have owned the boat for 3 months. The Starboard engine is eating up excessive engine coolant whereas the port engine is fine. I cant seem to find any leaks in the engine room. There is a smell of burning engine coolant when the engines are running. I thought it was an electrical smell initially but I think its engine coolant now that I see how much I am going through. I use about half a gallon (or half the reservoir) for every couple hours of driving at cruising speeds. The starboard engine does seem to be running a little hotter than the port engine- Just left of center on the gauge but not in the red. Any advice would be greatly appreciated.

[yachtman]

You have several places to look. First head gasket. Need to do a compression check. Could also be heat exchanger or exhaust. Pull the radiator cap when warmed up and and see if the antifreeze is bubbling. If it is it's probably a bead gasket if not then look at the other things.

[Norton_Rider]

I'm moving this to the Motor Yacht section. You may get more answers there.

[Ahaua]

Please let us know what you come up with. I have the same boat and engines so good info for future reference. Good luck in finding the fix.

Alex

[smitty477]

Best to pressure check the system with a rad cap pressure gage and see what the drop is. Once you have the drop begin to isolate areas by removing hoses and capping them off.

Examples.....

- do you have a heater of any kind on that engine? (water heater, space heater, etc)

- Do you have water cooled turbo's?

- When were the heat exchangers serviced last?

If the engines are otherwise running fairly well the head gasket is one of the last likely suspects. But you do not want to run like this as this problem could easily lead to other larger problems very shortly.

[ksanders]

if you are smelling coolant as part of the exhaust stream there are only a couple places it could be coming from.

Just think about the intake and exhaust systems for a bit...

air comes in through the air cleaner where it is compressed by the turbocharger which is cooled using coolant

Then the air goes through the aftercooler which is cooled using seawater

Then through the combustion chamber which is cooled by coolant

Back through the turbocharger as exhaust gas, again with coolant

then to the exhaust can where seawater is injected

If it were my boat, and I was sure that the coolant was going out the exhaust stream, I'd look first at the turbocharger.