I've been working my way to the radiator in my 2004 Mazda RX-8, which is buried pretty deep in its nose and set at an angle. It's been a production to get to it for replacement. Once I removed the engine radiator hoses (which I will also replace) I have removed everything explicitly called out in the workshop manual. That manual called for removing the radiator with the cooling fan module still attached, but it didn't explicitly say whether the assembly should be lifted up out of the engine bay or dropped down below it. People on RX-8 Club forums have reported success in both directions.

Either choice requires careful maneuvering. Lifting up means I have to be careful not to damage large stubborn wiring harnesses and refrigerant lines for air conditioning. Dropping down means being careful not to damage the air conditioning condenser dangling by refrigerant lines. The radiator's protruding top mounting brackets are especially dangerous to condenser fins.

I first tried lifting the radiator up but got tangled up between refrigerant lines and wire harnesses. I then tried going the other direction and had better luck carefully lowering it below the car onto the floor.

I removed the fan module and found several pieces of debris that has fallen in there over the life of this car. The largest piece was a rubber bushing that I didn't immediately recognize. I would later figure out it was part of the cosmetic engine cover. I lost both bushings over the years and my engine cover could only sit loosely in its position. Now that I've recovered one bushing I could reinstall the cover more firmly when I care to do so.

Some of the debris bounced around fan blades before settling down off in a corner. The old radiator on the left showed two arcs of damaged fins that lines up with the lower edge of fan blades. I set the replacement radiator down to the right for a quick side-by-side comparison to verify it looks largely correct. All the hose fittings seem to be the same diameter and located in the same places, as are all the attachment points for the fan assembly, the AC condenser, and chassis structure.

Transferring the fan assembly and mounting hardware, I had a new radiator assembly to install. I tried to reverse what I did earlier but had trouble lifting the assembly from the ground into the engine bay. This assembly is not heavy, but lifting it means bending over the front of the car and reaching through the engine bay out the bottom. It was an awkward pose with poor lifting leverage.

Next I tried to drop the assembly in from the top, but the same wire harness and refrigerant lines were in the way. This time I got smarter: I rotated the assembly 90 degrees so I could lead with the narrow side edge of the radiator, and that allowed me to clear refrigerant lines and wires. Once the leading edge is poking down under the car, I carefully rotated the radiator back into proper orientation.

So my opinion for the top route vs. bottom route discussion is: both! I think it's easier to let gravity help instead of fighting gravity. Which means removing old radiator out the bottom, then install new radiator from the top. This is especially true for someone working solo as I did. If there are more hands available, it should be easier to maneuver the assembly and lift against gravity so a different path may work better when installed by a team.

With the new radiator in place, I moved on to installing new radiator hoses and promptly hit my next problem.