marinized 240D running hot

I installed a marinized 240D into my old 45 foot ketch. To effect marinization, I bought and installed a Bowman marinization kit from Lancing Marine in the UK.

I pretty much rebuilt this old lady from the inside out and am in the throws of sea trials right now.

I'm however concerned that, when I run the motor under load for 20 minutes or so, the temperature gauge shows over 100 degrees C, and the heat exchanger is hot to the touch. Too hot to hold my hand to it for more than a few seconds.

I checked the water pumps, both seawater and freshwater, and these are fine. All hoses are clear too, and the heat exchanger is clear of calcification.

After some further meditation on the subject, I figured that perhaps the oil cooler may be too small and as a consequence, limiting the freshwater flow through the engine. I attach some photos of the installation for review.

Please advise if my hunch about the oil cooler is correct and if so, what water flow capacity oil cooler is required for this motor.

I look forward to hearing from you. My email address is andre.raath@gmail.com

Yours in anticipation

Andre Raath

 

I dont kmow much about marinizing, but should it not run about 115c and the heat exchanger should burn your hand at temp and load?

 

1. Check the thermostat is functioning correctly.
2. Check the seawater cooling flow is correct. This can be affected by the pulley ratio. So you need the info from Lancing how much seawater must flow trough the heat exchanger (l/min or gal/h) then see what rpm the pump you installed must have to provide that amount of water and check against current setup.

 

The suction hose into the saltwater pump seems small to my eyes. I'd start with a couple of checks:

What power level is used?
Is the saltwater pump driven off the camshaft gearing or by belt?
What does the bottom intake look like (free area, possible restrictions et c.)?
Can you see any bubbles travelling in the transparent hose?
Is the water from the heat exchanger going into the exhaust somewhere, and what is the shape of that junction?

 

The air intake filter looks woefully small for a diesel motor.
Bear in mind that at 16/1 compression, a 5 liter motor needs 80 liters of air per revolution.

 

Mercedes-Benz OM616 engine - Wikipedia https://en.wikipedia.org/wiki/Mercedes-Benz_OM616_engine
240d is 21+:1 compression, and 2.4l displacement.

 

No. It should run at about 80C and the heat exchanger should be at most lukewarm. The hot liquid runs through the inside tubes.

 

Well thanks!
Is it common on boats to have a temp gauge of the cooling loop, as opposed to the engine coolant?
If it is as you say, does this not suggest not enough flow of cooling water over the exchanger?

 

I have never seen gauge to show seawater temperature. It not possible to tell by the photo what the flow area is inside the oil cooler. A diagram of the cooling system hoses and other components would help.

 

Your question is not answerable with the facts provided.
Is there adequate airflow available?
Is the raw water system supplying enough cooling water?
Are the coolant reservoir and heat exchanger correctly specified?
Are there any choke points in the plumbing of the cooling systems?

At this point, in addition to my previous post, I’d recommend you get a laser thermometer and take temps along the flow paths of raw water and coolant fluid to find exactly where the heat is coming from.

Marinising an automotive diesel is tricky, and not always successful.
You are pushing a lot of boat with a relatively light rated motor that’s designed to operate on only momentary loading, which is NEVER the case with a marine diesel, so a low gear ratio and carefully selected propeller will be necessary.
Automotive diesels in heavy boats are commonly derated rather than hot rodded, so hopefully you have not selected your prop using max horsepower.

 

Right! but you said only 80C.
What do boat engines temp gauges measure? Not head coolant temp?
I would think an engine temperature gauge is expected to show coolant temp, which must needs be over 100C. If the coolant temp is not at least over 100C you are not even boiling off condensation in the oil and engine.

You must know something I do not. Please enlighten. What does the gauge measure?

meh, he bought a kit, no?
Welcome to Lancing Marine https://www.lancingmarine.com/index.html
all the info there suggests the temp gauge should be coolant temp, right?

 

It measures engine coolant temperature.

 

OM616 thermostats open at 79°C or 80°C (both temperatures where stamped). Maximum normal operating temperature of the coolant is 95°C.
There is a so called "winter thermostat" version that opens at 87°C, this should not be used in a boat.

 

Welcome to the forum, Andre.

 

Most marine diesels shoot for operating coolant temp of about 85*C, 100* is too hot, and would overflow due to expansion.
The coolant temp is not same as oil temp, although coolant is often used to cool the oil.
Raw water temp is not commonly found on an engine gauge panel, but most modern depthfinders have that capability.
Marine diesels will maintain a surprisingly similar gauge temperature through a wide range of raw water temps.
This is what a thermostat does.