Heating up in traffic - cooling system questions

[diesekte]

Stock aux fan, 16 slim SPAL pusher between engine and radiator. 89k mi S54 water pump and thermostat. E30 M20 manual rad with stock temp switch...150k(?) on both of those. Using the E30 brown plug in the Technica water pipe adapter - it seems to be grounded well as gauge is not jumpy at all.

I live in Texas and run the AC all the time, but my AC is pretty cold so I don't always have it all the way up.
Around town and on the freeway, I am almost always 3/8ths of the way up. After extended driving I will get to 1/2 (straight up) and when I get there for the most part it stays there.

When I am in extended stop and go or standstill traffic, the gauge will creep up to 3/4ths - I have never seen it go higher than that. When I had my M52 I would creep up in standstill/stop and go to maybe 5/8ths of the way. When I start moving again, even if only 20-30mph, the gauge drops back to dead center after only a few minutes.
The only constant I see between my M52 and S54 is the radiator, but it doesn't appear to be clogged or damaged. I'm definitely not leaking coolant (30/70 antifreeze/distilled water and 1 bottle of water wetter).

Aux fan seems it could definitely turn smoother but spins freely without any odd noises. I am on my 3rd resister in the last year or so, which makes me think maybe the aux fan motor is going out, causing too much drag, and burning up the resisters. Aux will come on with AC on but it doesn't seem to activate unless AC is on. Admittedly I have never gotten out and checked when the gauge is reading 3/4ths...

I've never had a problem bleeding the system so I don't think I'm having a big air pocket

1) Any insight? Anyone with similar issues?
2) If I go to the Koyo aluminum radiator, will that fit with this swap? Core is thicker than stock and there is maybe only an ass hair of clearance between the SPAL and the water pump pulley as it is

[rjmcdermott81]

This was on my s52 swap, but i had similar issues. I had an m42 radiator with a 16 inch puller and when I put A/C in it was heating up more than I was comfortable with. I switched to a Mishimoto radiator and because of the extra thickness I switched to two separate pullers - an 8 and 10 inch I believe. After that change my temps were much more under control. I'm in Austin so it's hot here as well.


Sent from my iPhone using Tapatalk

[superleggeram3]

Not sure if this help as I dont live in a hot climate but I used a e36 m3 mishimoto rad and kenlowe 16" fan on my s54 track car swap - havent had any issues at all stopped or on the move.

I also run waterless coolant and have a s54 mishimoto oil cooler which probably help.

[328ijunkie]

Are both fans running on high speed when youre sitting in traffic? Stock 91/99C fan switch isnt ideal i would say.

[diesekte]

Thanks for all the input, I may have to switch over to an aluminum rad then...

Dave,
I've got the lower temp switch on order now, it's cheap enough to give it a try. Things looks like they could be pointing towards the fans as I never heat up unless I am in about 15 minutes of stop and go, more stop than go. I can idle indefinitely though without heating up which is odd if it is a fan issue. The SPAL puller runs on only one speed and is just wired to 12v switched. The aux fan I will have to troubleshoot a bit more but as I only heat up in really terrible traffic, I haven't ever been able to get out and check if it's on high when I'm hot. If I were to get out of the traffic and drive to where I could pull over safely, the temp would be back down already

[butters]

You could also go to the thicker 3-row Z3M S54 radiator (part number ending 281). I'm looking at that option, just not sure if a puller fan is still possible...

[diesekte]

I replaced the temp switch for the lower temp version as Dave suggested, will see how it goes here in the next few days.

Apparently according to s54swap.com the Z3M radiator allows the use of the same SPAL I have, but I don't see how that is possible. Even after shaving the water pump nut all the way down I literally have about 3mm of space between the fan and the water pump pulley bolts. There is no other place or way to mount a 16" fan so it's not my choice of location on the radiator.

Does anyone know: do water pumps lose efficiency, then fail, or do they just stop working all together at once?

[R3Z3N]

^To answer your last question, the S54 water pump should not fail. The bearings or gasket yes.

I like the idea of 2 puller fans.

[rjmcdermott81]

This thread shows the 2 pullers mounted. With the single 16 inch I had similar clearance as you. The two pullers provided more airflow and actually made clearance better

http://www.r3vlimited.com/board/showthread.php?t=363777

Sent from my iPhone using Tapatalk

[diesekte]

Even with the lower temp switch, at 183 degrees the aux fan does not turn on by itself. It comes on when the AC button is depressed only. All fuses are good. It comes on both low and high speed if I jumper the female 3 prong connector but doesn't come on spontaneously....what gives?

For now I'm driving around with the female plug pins jumpered so that the aux fan runs on high whenever the car is on. Temps seem to stay around low 180s, so the problem is solved but in the wrong way. I really want the switch to work as it should without it unplugged and jumpered in a ghetto rigged fashion

[diesekte]

Bump, any insight on why multiple temp switches don't trigger the fan?

[diesekte]

bump - still looking for any info on getting the temp switch working proper

[Luke_M]

I had similar problems and finally got them sorted out. What I learned:

- My fans wouldn't come on via the radiator temp switch. Or if they would come on, it would be at weird times, long after the fans should have fired up. Ended up being air in the system which I thought wasn't possible. I ended up taking the switch out one day when it was running and found that nothing came out except air. I'd check this as it's free and is a good baseline.

- I originally only had a 16" pusher fan mounted directly on the condenser. That did alright but adding a 2" thick puller fan (thinnest I could find) on the drivers side of the radiator helped keep temps in place in the worst conditions, i.e. hot, humid and in stop and go traffic. Before it would creep up if I was in those conditions. It doesn't have to be a huge fan. I think mine is only a 12" but 8-10" would help as well. The pusher fan on the condenser pushes all that hot condenser air over the radiator which limits it's effectiveness. Adding a 2nd fan on the drivers side helps a lot.

Now that I got those small problems sorted I never see it go above the half way mark. All of this is with the z3 S54 radiator. About $155 shipped from various online vendors. Highly recommend that radiator.

[diesekte]

How did you get the air out that was on the upper passenger side where the temp switch is? I've bled and bled since I thought that was a problem previously but maybe I need to do something different?

[thmpr464]

For my issue, it was a combination of poor connection, faulty diode and auxiliary fan resistor. After properly rewiring using the BMW OEM waterproof plug kit and replacing the diode/resistor, the cooling system worked as it should including the AC system. I believe the poor connection was causing high current to the electrical system causing all weird things to happen - jumpy temp reading, intermittent AC cool/warm air, and surges.