Answer
Apr 07, 2023 - 02:58 PM
A heat exchanger or oil cooler is not made on the outside. Its made on the inside. We’ve seen sites and old salts with a great deal of experience that say that an oil cooler size is all that matters. That’s really a sophomoric answer and completely untrue. Heat transfer is based on three things primarily:
Surface area of the cooling tubes (so if the size is the same this cooling area would most often be the same).
Differential between the cooling fluid and the fluid being cooled (these are environmental circumstances and not related to the cooling device).
Fluid speed of the hot and cold fluid. This is the most important of the three as you can change the amount of cooling you will get by increasing the fluid speed. We’ve done this on test boats and by simply increasing the speed of your fluid pumps you will increase the efficiency of the cooler, dropping the temperature of the engine oil or other cooling fluid.
Fluid speeds can be increased by changing the fluid speed via the pump and also by changing what we call ‘baffling’ on the inside of the cooler. The number of the baffles and how much of the bundle they cover has everything to do with the fluid speed inside of the cooler. And everything to do with proper cooling. In all cases where it is reasonable we obtain the OEM unit for a new product and evaluate the inside of the cooler, duplicating it with much attention to accuracy so that the fluid speeds and backpressure remain the same. The term backpressure is another colloquial term in many industries for fluid resistance to movement or fluid friction. Technically there is no such thing as backpressure. It is commonly an increase in pressure due to an incorrectly made cooler or a cooler being used in an unintended way. If you’re measuring the pressure between the pump and the cooler, an incorrectly baffled cooler will have increased pressure which can harm the pump. If it has decreased pressure that means that the fluid speed may have decreased to the point where the cooler cannot do its job. And your engine temperatures will tell you if that’s the case.
And here’s the rub: sometimes these other coolers work just fine when installed. The damage to the pump happens over time and it may be the person you sell your boat to that has to deal with the issue. Standard oil coolers have standard baffling and are not often intended to be used as a replacement for an OEM cooler in most cases. They are an emergency replacement or some other interim fix. If someone is trying to sell you a non engineered cooler because they say they know better, you may regret the decision to allow them to proceed. Engineers who work in heat transfer are often very precise in their expectations and you should be also. And why would you want to try to save a small amount of money when all you need is a little patience to get the proper cooler - the one you need.
©2023 Mr. Cool Marine LLC
Surface area of the cooling tubes (so if the size is the same this cooling area would most often be the same).
Differential between the cooling fluid and the fluid being cooled (these are environmental circumstances and not related to the cooling device).
Fluid speed of the hot and cold fluid. This is the most important of the three as you can change the amount of cooling you will get by increasing the fluid speed. We’ve done this on test boats and by simply increasing the speed of your fluid pumps you will increase the efficiency of the cooler, dropping the temperature of the engine oil or other cooling fluid.
Fluid speeds can be increased by changing the fluid speed via the pump and also by changing what we call ‘baffling’ on the inside of the cooler. The number of the baffles and how much of the bundle they cover has everything to do with the fluid speed inside of the cooler. And everything to do with proper cooling. In all cases where it is reasonable we obtain the OEM unit for a new product and evaluate the inside of the cooler, duplicating it with much attention to accuracy so that the fluid speeds and backpressure remain the same. The term backpressure is another colloquial term in many industries for fluid resistance to movement or fluid friction. Technically there is no such thing as backpressure. It is commonly an increase in pressure due to an incorrectly made cooler or a cooler being used in an unintended way. If you’re measuring the pressure between the pump and the cooler, an incorrectly baffled cooler will have increased pressure which can harm the pump. If it has decreased pressure that means that the fluid speed may have decreased to the point where the cooler cannot do its job. And your engine temperatures will tell you if that’s the case.
And here’s the rub: sometimes these other coolers work just fine when installed. The damage to the pump happens over time and it may be the person you sell your boat to that has to deal with the issue. Standard oil coolers have standard baffling and are not often intended to be used as a replacement for an OEM cooler in most cases. They are an emergency replacement or some other interim fix. If someone is trying to sell you a non engineered cooler because they say they know better, you may regret the decision to allow them to proceed. Engineers who work in heat transfer are often very precise in their expectations and you should be also. And why would you want to try to save a small amount of money when all you need is a little patience to get the proper cooler - the one you need.
©2023 Mr. Cool Marine LLC
