Mishimoto E46 Non-M Aluminum Radiator R&D, Part 1: Stock Radiator Evaluation
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E46 325ci test vehicle
A peek under the hood reveals a clean and entirely stock engine bay. This would be helpful because we know what components we will need to incorporate into the design of our radiator. It will also help provide clearance information in regard to how much we can increase the size of our radiator.
Removing the Stock Radiator
Once the coolant was drained we set to work and had the stock radiator removed rather quickly. The process is fairly similar compared to the M3, but the electric fan installed on our manual test vehicle made removal a bit quicker.
Once out, we took a good look at all the features of the radiator to determine our course of action for developing a radiator of our own.
Along with the radiator, we removed the stock overflow tank and both the upper and lower radiator hoses. We will be evaluating the radiator expansion tank with an interest in developing an aluminum counterpart. The overflow tank on these vehicles is a common failure point, so we would like to develop a solution for that. As with the E46 M, we are planning to put together a silicone hose kit to replace the stock rubber units. If you need to replace your hoses, it makes sense to upgrade the material for greater longevity.
Take a closer look at the end tanks and hose connections featured on the stock radiator.
One of the more interesting features of this radiator is the cooler port for the automatic transmission, which is located on the lower driver's side of the radiator. Much like the E90 radiator, this port supplies coolant to the liquid-to-liquid heat exchanger that cools the E46 auto transmission. On a manual model, the plug in the base of this connection blocks flow to the bottom rows of the radiator.
In the automatic version, coolant flows to the base of the radiator and through a separate heat exchanger, which allows for the transfer of heat from the transmission fluid to the engine coolant. A thermostat regulates coolant temperatures for optimal efficiency. This stock system is both complex and interesting.
After numerous discussions and debates, we will be offering a radiator that functions with both manual and automatic models. Our engineers are up to the task of designing this unit, and we see a need for this radiator for auto models as well.
To connect the transmission cooler and overflow tank, a mounting plate is used to route fluid and additionally to provide a mounting point for the fan shroud.
As you can see, the manual and automatic mounting plates differ. The bottom image shows the two additional ports that move fluid to the external transmission cooler. A thermostat is also incorporated into the larger overflow port. As we mentioned earlier, this is a complex system and is not something we typically see.
Collecting Stock Radiator Dimensions
After deciding on the direction of our project, our engineering team began to collect dimensional data from the stock radiator. This meant mounting the radiator to our coordinate measuring machine (CMM) table and mapping the location of critical dimensions.
Once we have all the information needed from the stock radiator, we will begin to design our aluminum unit. Check back with us next time for a look at the 3D renderings of our plans for this radiator!
Thanks for reading.