Overheating At High RPM - how to react?

[Papawads]

Put aside the question of 'what is high rprm'
Put aside the question of 'why overheating'

Question is specifically: when you know your diesel inboard engine is overheating (the alarm is on) because you're at high RPM, what do you do next?

1. Turn the engine Off
2. Continue running in neutral (to keep water pumps moving)
3. Stand frozen with the Admiral repeatedly shouting your name, thinking that might help in some way.

Thoughts welcome
Papawads

[donradcliffe]

The first thing you try is to reduce the rpm by about 500, and see if the alarm goes away. Every boat I deliver gets tested at full rpm for 15 minutes, and about 1/3 overheat. Of those, about half will cool down if the power is reduced.

[Eagle ITA]

Originally Posted by Papawads

Put aside the question of 'what is high rprm'
Put aside the question of 'why overheating'

Question is specifically: when you know your diesel inboard engine is overheating (the alarm is on) because you're at high RPM, what do you do next?

1. Turn the engine Off
2. Continue running in neutral (to keep water pumps moving)
3. Stand frozen with the Admiral repeatedly shouting your name, thinking that might help in some way.

Thoughts welcome
Papawads

Answer 2 + switch on the blower (if you have one), and/or open the engine room to get the hot air out
But first of all check if the seacock of raw water is open

And then analyze why it's overheating

[ranger58sb]

Reduce RPMs, check for sea water flow, check for engine room flooding, watch gauge to see if temp starts to fall...

Diagnostics...

-Chris

[apoc]

When this happened to me, I was lucky enough to be in shallow water and calm conditions. I dropped the anchor and went below. Turns out that I forgot to burp the fresh water system after draining old coolant out and adding new coolant. I simply added more coolant, ran the engine for a bit in neutral, then ran it in reverse to put a load on it and didn't get the overheat alarm. Having fixed the problem, I simply pulled up the anchor and continued on my day.



Dropping the anchor gave me time to figure out things in a safe and calm manner.

[Shrew]

1) Look to see if there is water discharging with the exhaust.

2) Inspect engine for any water leaks.

3) shutdown the engine

4) close seacock and check seastrainer.

5) Inspect impellor

6) Inspect heat exchanger

6) Allow engine to cool and see if there is any coolant in the coolant reservoir.

It's typically only going to be a handful of things.

clogged intake or sea strainer.

failed impellor

clogged heat exchanger

no coolant on the closed cooling side (failed heat exchanger)

exhaust elbow.??

[team karst]

Originally Posted by donradcliffe

The first thing you try is to reduce the rpm by about 500, and see if the alarm goes away. Every boat I deliver gets tested at full rpm for 15 minutes, and about 1/3 overheat. Of those, about half will cool down if the power is reduced.

OR, keep Don away from the boat!

btw; my surveyor overheated my Port eng during his WOT test....