Heating up in traffic - cooling system questions

[diesekte]

I tried to rebleed many times, and tried taking out the temp sender and coolant came out immediately. I don't think i have air. Seems the fan refuses to run on high even though wires and relays/fuses are good. Not sure what the problem is but I have jumpered the temp switch connector so fan runs on high always. Working well and staying constantly cool now

[Luke_M]

That's probably a good way to go. I really need to get one of those.

[thmpr464]

I just bought the coolant purge system from ECS to properly purge the coolant system.

[Luke_M]

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?

I simply kept the switch out of the radiator until it started to spew out coolant. Not ideal and you better be fast and be ready to get burned. A glove soaked in cold water helps some haha

Despite the hillbilly method it worked a lot better afterwards.

[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.

[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?

[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]

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

[diesekte]

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

[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

[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

[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.

[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?

[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]

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