Thread: VVL coolant boiling over

a lot of times you won't. a while back i sent a sample to blackstone that "looked" normal only to find out it held 2.5% antifreeze. they recommended "very short" 500 mile oci's until the h/g was replaced. but, there i go, getting ahead of things.

Thanks. Whats strange is, it seems to do it when it feels like it. I drove the car for 45 minutes yesterday and nothing, then it drive it 20 min and it does it, then 25 min and nothing etc.

I'll try Ashton's method

definitely!

similar situation happened with me but it was my fan switch.... seems that even though the fans did come in, it took too long to do this and as a result in heavy driving cause a similar outcome

didnt see this.... makes me think more now that it could be the fan switch.... if u do change it please get a NEW one.

I have figured it out, the coolant fans aren't coming on. At all.

I discovered this after doing 4 dyno runs with the hood open and not one time did they come on during an hour long session while the coolant bottle was boiling over again.

Have no idea why they aren't coming on.

test the fans by grounding them. if they cut on the fans are fine. Then move on to the relay that controls them and the head temp sensor.

on the dyno you can use the passenger compartment heater to draw down the temps. temp on hot, fan on hi. keep the rpm's ~2k to circulate the coolant. makes a huge difference. bring the temps down to ~185-190 between runs, then shut the fan switch off before you "nail it". but for sure, get the radiator fans a runnin' soon. just remember, they won't kick on till ~210-212 anyway.

Yep. I also am running all Distilled water and a bottle of Redline Water wetter. Sounds ridiculous to run that in January in Philadelphia BUT it is 65 degrees today and I did it just for the dyno, and i'll replace with some antifreeze this weekend as it's still not even Febuary, sure it will get cold again. probably not 2 degrees though like last week.

Well the likelyhood of two fans going out at the same time is unlikely so more than likely the fans are still good. You really only have two other options. The ecu's temp sensor which is the red coolant temp sensor or the relay or the fuse for the fans. id say start with the cooling fan fuse, then check the relay to make sure it has the power at pin 30 and at pin 85 or 86 for the signal, whichever pin 85 or 86 has power take and ground the other side of that. On b13's its the one with the light blue wire is the signal ground. Just make a jumper and see if the relay kicks on, if it doesnt its the relay, if it does then its ecu/temp sensor related. If the circuit for the fans checks out then replace the coolant temp sensor. Its cheap and more than likely the cause if the circuit for the fans checks out ok.