Just started my 305 for the first time today and I was breaking in the motor. I used water incase of any leaks without the thermostat. Aftera about 10 minutes of running both hoses got real hot and the cap vent blew open. Do I have a problem here or is the pressure from the water boiling off in the engine. Hard to say if it is over heating Temp cage is inop trying to fix that now.Is my pressure problem from the water boiling over and expanding. No water in oil and no white smoke. I did see water circulating the radiator when I was filling it .

 

If you used straight water, and it wa sitting for awhile, its most likely just the water steaming up. Try 50/50 mix, and if it happens again, then ask.

 

yeah try it with some coolant i use a 50/50 mix also.

 

After a rebuild or newly filling with coolant the cooling system has to blow out a lot of air when it first heats up. Then when it cools it sucks in coolant from the header tank. It can do that a few times before it stops blowing out when heating up.

 

I just put in a rebuilt 350, which runs just fine except that neither cooling fan came on when I was first idling it, and the temp gauge was almost in the red. I grounded terminal B on the ALDL and the fan kicked on. The CTS I put in was pulled off the V6 that I took out, and the V6 never had any overheating problems. However, I used straight water to fill the radiator and reservior, and I was wondering if perhaps the coolant wasn't reaching the CTS, or something similar. I have a 180* stat in there, and there were no major coolant leaks. Any ideas?

 

Check the fan switch in the passenger side head or the relay it is right next to the powerbooster closest to the fender.

 

I see you did the same thing I did. The water is steaming up put some 50/50 mix of coolant in it should stop overheating. More than likely it is the fan switch though

 

It is possible that the sensor is not imersed in coolant so although the engine is getting hot, the sensor is not seeing it. That is possible maybe until the engine gets fully primed with coolant. But it could also easily be the fan or the thermostat.

 

Today I tried putting in a new CTS, since the other one had 76000 miles on it - just to be on the safe side. When I pulled the old one out, it dumped lots of the water, so I'm pretty sure that the CTS was getting coolant. All the other switches are new, but I'll check them. Could the relay be an issue if I ground the diagnostic terminal and the fans come on? I didn't think that they could come on at all if the relay was bad.

 

It isnt the cts its the fan switch in the passenger side head it has a single dark green wire going in to it. If you can ground out the relay and the fan works, it is probably the fan switch not the cts the cts is for the computer. I see your in Pullman WA going to WAZU I take it.

 

My service manual says that the main fan is controlled entirely from the ecm,and the secondary from the switch on the pass side. I'll check it, but I don't think that's the problem.

Yes, I go to Wazzu, and I graduate in May.

 

so what happens if you just hard wired the fan into teh ingition so any time the car runs the fan is running all the time??