alright i just started up my z6 swap. i put the coolant in the radiator and started the car. i left the radiator cap off and waited for about 15 minutes for the engine to heat up and the fan could come on twice (like the manual says). the fans never came on, and coolant began to overflow the top of the radiator. when i did the swap i got a 5g fan switch connector and spliced it into my wiring for the EF fan switch. (i will be checking this first to make sure the wiring isn't mixed up). why is the radiator overflowing? is it because its too hot? TIA

 

ahh i forgot to mention. the temperature gauge on the cluster was working and was reading the normal just below half. i wasn't throwing any codes. help me out!

 

when the car is idliing it is normal for the radiator to overflow some because the coolant is expanding. check the wiring on the fan switch.

 

yeah but the manual tells you to idle the car with the cap off... do you think it would have overflowed still if the fans worked?

 

do you have any air in the system coolant??

 

probably... thats why you run it with the cap off though right?

 

you can also leave the cap on, and connect a hose to the bleeder valve (right above the header) and let it bleed itself from there so you don't have coolant going everywhere

 

I've had the same problem for a while now. Replaced the thermostat, cooling temp switch, and still nothing. As for now, I wired the fan so it's on all the time, and I'll probably end up installing a switch if I can't find the problem. I hate it but it gets me through.

 

The fan switch is a very simple circuit, if the switch is new, one pole of the switch must go to ground, the other must go to the fan. At the fan, the other wire goes to switched power (ignition acc)

This isn't hard to trace, fix your fan, i know if i let my b16 idle for 15 minutes with no fan, i'm overheating after 10 minutes. may wana check that temp sending unit on the side of the head under the distributor

 

i took the two wires that went to my fan switch on my a6 and spliced wires from the connector of the z6 fan switch to those two wires. the temp sending unit also controls the gauge inside the car correct? i'm getting normal readings there. i just got back from taking the car for a drive and i know the thermostat is working because both radiator hoses were hot. i didn't get any steam this time though. i'm gunna take it out again when my dad gets home with my new distributor o ring. mine was leaking all over. thanks for the help so far...