Dougcole
Guru
Mainship 400, twin Yanmar 4LHA-STP.
Here's the scenario.
Have done quite a bit of cooling system preventative maintenance in the last 24 months, here's a rundown:
24 months ago, sent raw water pumps off for rebuild.
16 months ago, replaced both elbows and mixers
12 months ago, flushed with barnacle buster.
10 months ago, had intercoolers serviced.
4 months ago, replaced coolant, and flushed.
2 months ago, replaced impellers.
Engine has never run hot, 173 to 180 degrees, under load.
Coolant in overflow canister always is below "full cold" mark.
Put about 100 hours on the motor(s) after the coolant change, including a 8 hour run across the stream and banks to the Bahamas at 2,800 Rpm. Engine never ran hot, right at 180 degrees. No coolant leaks.
During a routine engine check, I added a little (a few ounces) of coolant to the overflow canister even though the level was right where it always is. Not sure why I did this, it's never been a problem before, I do dumb things sometimes. Ran the engine quite a bit (15 hours) after this, but all at lower speeds, none at fast cruise. No leaks.
Crossed the banks to West End, 3 hours at 2,800 RPM. Go to the marina and there was what I think is watery coolant under the tranny end of the port motor, hard to say how much as it flows into the bilge and the bilge pump pumps it out. At least a quart. There is a sump of sorts under the aft end of the motor that is seperated from the rest of the area under the motor by a stringer. The fluid was almost all in this area, but some appeared to have run into the bilge.
The engine room smelled of coolant. No fuel or oil or coolant or transmission fluid leaks on the diapers under the engine. The level in the overflow canister is back where it always is, just below "full cold" and is a nice bright pink. Stuck my finger in the reservoir (it's not easy to see in there) coolant is up to the top. No milky oil or tranny fluid.
Cleaned up the mess and ran the engine while I watched. Couldn't see any leak.
Crossed the stream the next day at 2,800 RPM, 5 hour run. Get home and there is a mess again. Clean it up, watch the motor run again, this time 15 minutes, it gets up to 150 degrees at fast idle as it is still warm from the run. No noticeable leak.
Again, the engine didn't run hot, 180 degrees. Perhaps 2 to 3 degrees hotter than normal, but nothing that concerned me.
I also noticed that there was some coolant in the lazarette, the genset is in there, but it's not running hot either. I have not had a chance to inspect it for leaks. It ran about an hour during both crossings.
No jugs of coolant leaking in either the lazarette or the ER.
I'm kind of at a loss, I'll be back at the boat in a week or so. Where should I start?
Here's the scenario.
Have done quite a bit of cooling system preventative maintenance in the last 24 months, here's a rundown:
24 months ago, sent raw water pumps off for rebuild.
16 months ago, replaced both elbows and mixers
12 months ago, flushed with barnacle buster.
10 months ago, had intercoolers serviced.
4 months ago, replaced coolant, and flushed.
2 months ago, replaced impellers.
Engine has never run hot, 173 to 180 degrees, under load.
Coolant in overflow canister always is below "full cold" mark.
Put about 100 hours on the motor(s) after the coolant change, including a 8 hour run across the stream and banks to the Bahamas at 2,800 Rpm. Engine never ran hot, right at 180 degrees. No coolant leaks.
During a routine engine check, I added a little (a few ounces) of coolant to the overflow canister even though the level was right where it always is. Not sure why I did this, it's never been a problem before, I do dumb things sometimes. Ran the engine quite a bit (15 hours) after this, but all at lower speeds, none at fast cruise. No leaks.
Crossed the banks to West End, 3 hours at 2,800 RPM. Go to the marina and there was what I think is watery coolant under the tranny end of the port motor, hard to say how much as it flows into the bilge and the bilge pump pumps it out. At least a quart. There is a sump of sorts under the aft end of the motor that is seperated from the rest of the area under the motor by a stringer. The fluid was almost all in this area, but some appeared to have run into the bilge.
The engine room smelled of coolant. No fuel or oil or coolant or transmission fluid leaks on the diapers under the engine. The level in the overflow canister is back where it always is, just below "full cold" and is a nice bright pink. Stuck my finger in the reservoir (it's not easy to see in there) coolant is up to the top. No milky oil or tranny fluid.
Cleaned up the mess and ran the engine while I watched. Couldn't see any leak.
Crossed the stream the next day at 2,800 RPM, 5 hour run. Get home and there is a mess again. Clean it up, watch the motor run again, this time 15 minutes, it gets up to 150 degrees at fast idle as it is still warm from the run. No noticeable leak.
Again, the engine didn't run hot, 180 degrees. Perhaps 2 to 3 degrees hotter than normal, but nothing that concerned me.
I also noticed that there was some coolant in the lazarette, the genset is in there, but it's not running hot either. I have not had a chance to inspect it for leaks. It ran about an hour during both crossings.
No jugs of coolant leaking in either the lazarette or the ER.
I'm kind of at a loss, I'll be back at the boat in a week or so. Where should I start?