espz06

Ahh, those hot summer days...here's another cooling question. 2002 Z06 here, temps started going well over the usual 220, and up to 250+ with some boil over. Checked fluids, added a little dexcool and some water wetter, and it was still doing it. Then I noticed at that 250 degree mark the right (passenger side) was NOT spinning. I know it's controlled, but it should've been working over time at that point, right?

I checked the fuses that I could, but I don't have an O meter to check the relays. Anything else this could be? Is this user-serviciable? I've done a lot on this myself, brakes, ebcm rebuild, etc...but if this entails tearing out the radiator or some such nonsense, then I'll probably take it down to Scotty's Vettes and let them do it!

BlackZ06

Turn on your A/C and when the coolant reaches about 185 degrees you should see BOTH fans come on in LOW speed mode.

If the coolant temperature reaches about 226 degrees, you will see a transition to BOTH fans running in HIGH speed mode.

I'm guessing you're loosing the right fan when they switch to HIGH speed and that it works in low speed mode. If that is the case check fuse 46 (30 Amp) in the Underhood fuse block. If the fuse is good, then test to see if relay 43 is the problem. To test, remove the relay and jumper 12 volts to the WHITE wire ... the right fan should run in HIGH. If the fan runs, replace the relay. If the fan doesn't run, the fan has failed.

Sherminator

You can pull the fans without pulling the rad. Just drop the sway bar off the cradle, unhook the electrical, push the fan up and off the hooks holding it to the rad, and lower it down twisting it either way as you go.

jjk2509

I had a similar problem - check the bolt that connects the fan to the shaft. The bolt came loose and the shaft was spinning but the fan was not. I was able to install a new bolt without removing anything.

Best thing to do is check and see if the fan is loose with the engine off.

Good Luck

striper

[QUOTE=BlackZ06;1566558086]I'm guessing you're loosing the right fan when they switch to HIGH speed and that it works in low speed mode. If that is the case check fuse 46 (30 Amp) in the Underhood fuse block. If the fuse is good, then test to see if relay 43 is the problem. To test, remove the relay and jumper 12 volts to the WHITE wire ... the right fan should run in HIGH. If the fan runs, replace the relay. If the fan doesn't run, the fan has failed.

I wanted to try this on my own car, due to occasional high temps in traffic. Fuse was okay so I removed the #43 relay. I was not able to tell which slot was for the white wire to jump 12v to. Rather than use trial and error, I lifted the fuse block up. I couldn't tell a damn thing and didn't want to create any new damage, so I reinstalled the fuse block. How do I know which relay slot is for the white wire? Also, since the relay can be reinstalled in either direction, does it matter which way or how can I tell the correct way to reinstall? BTW, doesn't the black relay turn them both on at high speed or am I wrong? That's what I thought might be the case after trying to figure out the wiring diagram in the shop manual.