E28 M30 swap with modern electric fan issue

[rosebl]

I’m finishing an M30 swap on my 1986 E28 535i and noticed the coolant temp climbs slightly in stop-and-go traffic only when the A/C is running. I already replaced the radiator, thermostat, and fan clutch, but the issue still appears after about 20 minutes of driving. Has anyone tested a slim electric fan setup that actually keeps temps stable in hot weather without overloading the factory alternator? Ragdoll Hit

[Vincenze]

AC Solutions sells a condenser with an electric fan.

https://www.acsolutions.co/collections/e30

[Panici]

I've used SPAL fans with deleted mechanical fans.
No AC systems though which add a lot of heat load.

[LindaWright]

If it's only happening with the A/C on, I'd be looking at airflow before anything else. A lot of people jump straight to electric fans, but a healthy cooling system on an M30 shouldn't be struggling in traffic. I'd check the fan clutch again, make sure the condenser isn't clogged with debris, and verify the aux fan is kicking on at the correct speed. My money is on one of those before the radiator or thermostat. Geometry Dash

[felixandrea]

I’m finishing an M30 swap on my 1986 E28 535i and noticed the coolant temp climbs slightly in stop-and-go traffic only when the A/C is running. I already replaced the radiator, thermostat, and fan clutch, but the issue still appears after about 20 minutes of driving. Has anyone tested a slim electric fan setup that actually keeps temps stable in hot weather without overloading the factory alternator?

Before switching to a slim electric fan, I'd make sure the issue isn't airflow through the condenser. If temps only creep up with the A/C on, that usually points to insufficient airflow at low speeds rather than a radiator or thermostat problem.heardle

I've run a 16" SPAL puller on an M30 and it kept temperatures stable even in summer traffic, but I used a proper relay setup and a high-output alternator. Most of the cheap slim fans don't move enough air for an M30 with A/C. Also check that your fan clutch is actually locking up when hot and that the condenser isn't partially blocked with debris. A healthy stock clutch fan should normally handle stop-and-go traffic without temperature rise.