Hello, I just got an 89 300zx, the old owner told me that the fan clutch was not working, I tried and the fan works, however when drving the car home , as the old owner predicted, the needle start to rise , half, then almost 270, I stoped waited for almost and hour and start again, got home and let it rest. Today morning , I started the car, again fan working, however when I started the car I saw the needle flick between half, and ,270 , then go back to the middle and stay there, I had the car on for about 20 minutes,I went to the front and again saw the fan working, turned off the car check again the front , the cap of the radiator was making a noise like letting water out,, besides that everything seemed ok, what do you think is the problem?, do you think the fan clutch is not working? Water temp sensor? Water tem sender? , helpfully you guys can hide me to the rigth track ...thanks

if you are driving at more than 20 mph the fan has nothing to do with how much cooling air hits the radiator. If the shroud is missing then it will heat up when idling. the stock gage is nortoriously unreliable if that is what you are relying on. Check the sender. Is she full of coolant. the vg30 sometimes has air bubble that impedes cooling. is the coolant the right mix. thermostat could be haywire. you need to get an accurate read on the coolant temp. beg borrow infrared gun to check. expansion tank has coolant?? when you pull the rad cap coolant is full??

i went to check coolant, since the morning i am missing about 1/8 of gallon, i just fill it up top., one more thing, yesterday on one stop i did while i was bringing the car home, i opened the hood, and i could see esteem coming out of the radiator cap., by these symptoms what could it be?

Go to a radiator shop and have them test the coolant for exhaust gases, you may have a bad head gasket. Also may need a radiator

or your rad cap could be shot. is the hose to the expansion tank open? a kinked hose prevents coolant going to the expansion tank and will cause a leak from the rad cap. you need to determine if the engine is actually overheating. a rad shop can do that but probably not free. Harbor Freight has an infrared gun fairly cheap.

Just a though...
Now that you mention the reservoir, I see it and is always full, by the way I'll try to go today to HF and check out that infrared thermometer. I'll keep you updated

Thanks for you time

Update...

filled up with water , replaced the radiator cap, start the vehicle, let it run for about 20 minutes. waited and i didn't notice steam coming out of the cap, however the gauges, they are acting up , the temp gauge did the same thing , start cold ,went to 270 , and came back to half way. i will flush it this weekend.
i'll let you know the outcome, thanks for the Z31 Album,

Also , where is the Coolant Temperature Sender?

buried atop the engine. I forget exactly where but i think passenger side between the last two cylinders. Get a flashlight and look carefully you should be able to find it.

I feel your pain as mine is the same way. Flush it twice, changed the waterpump, t-belt, thermostate, thermo sensor and stock boost, still overheats. Full maintenance on it, plugs, wires, dizzy cap and rotor, same results yet. I hate to take it to the shop but I guess that'snext. Good luck buddy.

Jason,

lets not give up! , they dont make cars like this one no more!

I'll Flush it this weekend, lets see what's up!!

Update

just did the "newspaper" test on the radiator fan, and as it was suspected the fan stopped once the newspaper hit the blades,

well now i know the fan clutch its bad

lets see what happen with the radiator flush