Supa Troopa Posted October 2, 2009 Share Posted October 2, 2009 I have a 1978 280z and I just finished successfully putting back together the top end and it runs great. I had the head resurfaced not because it over heated before, but I just sent it to the machine shop for a good dip and have everything checked out. So about the thermostat. I filled up the radiator and let the car idle for maybe 20 minutes and the radiator fluid never dropped. I kept trying to squeeze bubbles out of the lines thinking here was a lot of bubbles in there and not to many came out. During this whole time, the temperature needle never went half way on the gauge. I filled up the coolant reservoir, threw the radiator cap on and took it for a spin. Drove it around for maybe 5 or 10 minutes and came back and let it sit for a while. I would then pop the cap off and the fluid was still at the top. I did this again and then let the car sit for several hours after driving it and when I checked it later that night, the coolant was still to the top of the radiator. I did not notice any collapsing of the hoses, it never once took anything or over flowed the reservoir, and honestly as I would drive the car, the temperature needle would drop some. My main question/concern is that I never saw the thermostat open and topped it off and now I am worried the car is going to overheat. I put the coolant temperature sensor and everything back in its proper place but I will take a picture of everything just to get some reassurance. I just don't want to overheat the car because the thermostat isn't opening, or is it? I know I can take it out and test it in boiling water but has anyone had this happen to them? Is it normal for a z to just take whatever is in the radiator and run with it? I've never ran across this issue before where there wasn't signs of overheating, that is why I am concerned. I never had problems before with the car. Thank you. Quote Link to comment Share on other sites More sharing options...
jc052685 Posted October 2, 2009 Share Posted October 2, 2009 So your worried cause the level never dropped? My fluid does not drop much if at all on a refill. Quote Link to comment Share on other sites More sharing options...
Supa Troopa Posted October 2, 2009 Author Share Posted October 2, 2009 Yea my fear is that the fluid hasn't sufficiently filled the block since the thermostat is closed. I stuck a thermometer in the coolant when it was idling for a while and it got upwards around 160 and that is before I drove it around. I am not used to having a car with a fan that runs 24/7 though My blower doesn't work in the car so I can't tell by turning the heater on. I want to say its fine, but there is always that what if. Like I said, there are no common signs of overheating such as collapsing hoses, overflowing reservoir, temperature needle through the roof... I am used to letting the car idle til it heats up, then the thermostat opens and you fill it up the rest of the way and be done with it and since that hasn't happened yet to me on the car I am worried something is wrong. Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted October 2, 2009 Share Posted October 2, 2009 My fluid level never dropped after I swapped thermostats, and It's going on probably 1.5k miles, and I haven't even had to top it off. Idles normally, drives normally, etc. Quote Link to comment Share on other sites More sharing options...
woldson Posted October 2, 2009 Share Posted October 2, 2009 Pumping the hoses work pretty good. If you see the needle move down wards, that is probably the thermostat working. Quote Link to comment Share on other sites More sharing options...
Iceman Posted October 2, 2009 Share Posted October 2, 2009 The Z doesnt have any weird angles for the hoses, so you arent likely to get air trapped. If you do get air trapped, there is no mistaking it, your needle will skyrocket because it will get extremely hot where the sensor is. Another easy check is to touch the top hose after the car has been running for a while. If it's hot, and not full of air then your thermostat is working. Quote Link to comment Share on other sites More sharing options...
Supa Troopa Posted October 2, 2009 Author Share Posted October 2, 2009 Ok maybe I am just worried that I messed up somewhere. Thanks for your input, I guess it was to good to be true, that's why I worried lol. Thank you very much. Quote Link to comment Share on other sites More sharing options...
woldson Posted October 3, 2009 Share Posted October 3, 2009 Ok maybe I am just worried that I messed up somewhere. Thanks for your input, I guess it was to good to be true, that's why I worried lol. Thank you very much. When somthing goes pretty much perfect, no blood even spilled, I tend to worry alot as well;) Quote Link to comment Share on other sites More sharing options...
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