Engines running warmer in warm summer waters?

[kashurst]

Properly set up the KAD and KAMD engines will run all day long in the Med at 32 degs C and sit at 82 degs C. Med marinas are full of KA(M)D engined boats.
Unfortunately there is loads of misleading twaddle on the internet about this series of engines. Just stick to the letter of the Volvo manual and you will be fine.
My last boat had a pair of KAMD 300s on shafts driving a Rodman 38 flybridge in the Med - brilliant engines. Cruised at 3100rpm engines sat at 82 C all year around.

 

[NBs]

Yes .

In spring and cool water i saw ~90 deg on my kad44 at 3500 rpm , now at around 20deg watertemp i see ~93 .

What temps do you see with your kad300 on plane ?

Hi,

I wonder if you have changed the coolant recently. Old coolant loses its heat transfer properties and corrosion begins.

NBs

 

[Roughcut]

Interesting thought, thanks. I change it every 2 years as per the VP schedule.

 

[NBs]

Great, that's out of the question then. As many have said, it might be time to service the heat exchanger. If not yet, because 2 degrees is not a problem, but if it continues to rise in the future, you know what to do.

Have you checked the raw water filter? You may find all kinds of things in there, such as plants, fish, etc., which can slow down the water flow. They may also be in the inlet hose if there is no strainer.

 

[Roughcut]

Thanks - I appreciate everyone's ideas, thoughts and comments - but just to be clear, I wasn't asking for help to sort out a cooling problem - I was merely wondering if anyone had experienced slightly higher running temps this summer - especially with KAD engines. I'm genuinely grateful for people's suggestions for what I should be servicing, but with the help of a couple of great VP engineers in North Wales, I'm across all that kind of thing. I was really trying to see if anyone had any personal experience. It sounds like the answer is "no"! In which case I'll abandon my cod thermodynamics theories and return to the simple joys of summer boating. Thank you all who responded, and my apologies if the original question wasn't clear enough!

 

[Forty_Two]

One more thing to check, hose delamination. I had it happen on a 32mm hose between the last heat exchanger & exhaust injection elbow on one of my Perkins Sabre M135's.

 

[NBs]

Hi,
I have about 10 years of experience with kad44 double installations.

Temperatures remained stable with sea temperature fluctuations between 2°C and 22°C.

The only difference is the time it takes to reach the temperature.

The current Cummins qsb stays at 78°C, except during acceleration, when it momentarily reaches 80°C and quickly returns to 78°C.

NBs

 

[aerobat]

I have about 10 years of experience with kad44 double installations.

Temperatures remained stable with sea temperature fluctuations between 2°C and 22°C.

The only difference is the time it takes to reach the temperature.

what temps did you have on the '44 during high loads ?

 

[NBs]

what temps did you have on the '44 during high loads ?

I remember 86°C IR measures and gauge looks 92/88

 

[aerobat]

I remember 86°C IR measures and gauge looks 92/88

Thanks . Like said ~90 is also what i see on the instruments .

 

[Momac]

Hi,

I wonder if you have changed the coolant recently. Old coolant loses its heat transfer properties and corrosion begins.

NBs

I think the corrosion may begin because the coolant loses its corrosion protection properties .
I don't think the cooling properties really are reduced with time.

 

[NBs]

I think the corrosion may begin because the coolant loses its corrosion protection properties .
I don't think the cooling properties really are r

Etsi

Research on Coolant Aging and Engine Overheating​

There are several studies that explore the relationship between coolant aging and engine overheating. Here are some key findings from recent research:

Key Studies​

1. The Effect of Using Variations of Radiator Coolant
   This study, published in January 2025, investigates how different types of radiator coolant affect engine cooling effectiveness and the corrosion rate of radiator materials in 1300 cc cars. It highlights the importance of maintaining coolant quality to prevent overheating and ensure optimal engine performance.
2. Effect of Aging and Interaction of Cooling Fluid
   A 2019 study focused on how aging coolant interacts with heat exchanger materials during long-term durability tests. It emphasizes that as coolant ages, its properties change, which can lead to reduced cooling efficiency and increased risk of engine overheating.

Findings​

• Coolant Quality: The effectiveness of engine cooling is significantly influenced by the type and condition of the coolant. Aging can lead to a decrease in thermal conductivity and an increase in corrosion, which can contribute to overheating.
• Corrosion Rates: Older coolants may not only lose their cooling properties but also promote corrosion in engine components, further exacerbating overheating issues.
• Maintenance Recommendations: Regularly checking and replacing coolant can help maintain engine temperature and prevent overheating.

These studies underline the critical role of coolant maintenance in engine health and performance. If you're interested in more specific details or additional studies, let me know