S52 Cooling Issues

[domtringali]

I have a 1990 325i sedan that I put a S52 in. My setup is a mishimoto radiator, stock water pump, aluminum thermostat housing, and 16” spal fan. When I idle for extended periods of time once the engine is up to temp, coolant temp starts creeping until I am either moving or put the defrost on. Is there a different setup I should use? Would a m42 radiator work better like I have seen other people say the use and have no problems? I am in Atlanta where it gets pretty hot during the summer

[DesertBMW]

spal can't do it, got to run the mechanical fan

[RenaissanceMan]

Fwiw I’m also running a Mishimoto with a high CFM Spal pusher fan mounted in front of the a/c condenser. My fan activates off of a thermostat but is on by default when the a/c is on. We are experiencing pretty hot weather in Nashville and my temps never get above 205-210. Maybe I’m just lucky but it has worked pretty well for the last 6 years. What temp thermostat are you running?

[domtringali]

Fwiw I’m also running a Mishimoto with a high CFM Spal pusher fan mounted in front of the a/c condenser. My fan activates off of a thermostat but is on by default when the a/c is on. We are experiencing pretty hot weather in Nashville and my temps never get above 205-210. Maybe I’m just lucky but it has worked pretty well for the last 6 years. What temp thermostat are you running?

I’m running a stock thermostat. I just ordered a lower temp thermostat and a better fan controller to see if there are any improvements

[domtringali]

spal can't do it, got to run the mechanical fan

there isn’t enough clearance to run fan clutch setup

[RenaissanceMan]

I’m running a stock thermostat. I just ordered a lower temp thermostat and a better fan controller to see if there are any improvements

I’ve run both the stock and the lower temp and the lower temp helps some overall.

[mtech325]

The Mishimoto radiators seem to be thicker than stock, so fan clutch likely won't fit. I tried to install an e36 diesel fan with the Behr Z3M radiator and it wouldn't clear either without trimming blades to clear the vanos bump in the valve cover. So far the only way I've personally seen a fan clutch work on a 24v swap is to use the m20 fan with the slimmer late model e30/e36 OEM style radiator with the thinner core, but it's a tight fit and it requires radiator removal to pull the fan (such as for changing a belt).

The setup I've used for hot climate daily driving is:

Z3M s54 oem replacement radiator (thicker than stock e30/e36)
88c thermostat (I tried 80 degree m20 unit as well and car had a hard time warming up past 1/4 mark, especially on freeway)
Spal 16 inch electric pusher fan
80/88c fan switch from 318ti

So far this has worked for the past 6 years. Temps stay just below the halfway mark on the cluster aside from the hottest of days in traffic, but fan kicks on just after halfway marker. My water pump started to fail a few months ago and I replaced it with the EMP Stewart pump to try it, but the regular water pumps seem to work perfectly fine when in good condition.

[Digitalwave]

If your fan is a pusher, see if you can fit a puller. They cool more efficiently. Make sure to use the rubber gasket that Spal sells so it can seal against the radiator without hitting the fins. Also, a stock/OEM radiator will have better fin density than your Mishimoto.