hot!hot!hot!

[byrdog24]

i recently posted my '85 300zx was overheating.i had a friend mechanic that told me to replace the fan clutch.i did and ran the car for about 30 miles non stop and didn't overheat.on my way home however within 10 miles it was at boiling point.heater core has been removed but water flows though the neck easily.seems to be under alot of pressure and won't pull water out of resevoir it just keeps filling up.im at a loss any suggestions would be helpful.

[AZhitman]

There's a leak betweeen the radiator and the overflow.

It's pumping water into the overflow, but won't suck it back as it cools... Instead, it's sucking air, which rapidly replaces the water in your cooling system.

Replace the hose between the radiator and overflow, and make sure the pipe into the overflow is submerged at all times.

[evildky]

is it spewing coolant from the overflow? if so you might havve a bad HG and blowing exhaust through the cooling system, the cooling systems on the Z31 are a PITA weiht the low hiddn angled radiator, I replaced everything on mine and it still ran hot till I replaced the radiator, it flowed, just not enought o keep the car cool

[byrdog24]

its actually spewing from the radiator cap.i followed advice from the other guy sorry don't remember and it seemed to help.but when i drive long distances at 60+ it overheats and comes out the cap.it was however filling up the resevoir but i cleaned it and is not doing that now.how can i tell if i do have a blown head gasket?im use to chevrolets and most of the time water would get in oil if this happened.thank for the help, this car runs like a top and is in very good shape but is my first in the import ownership.

[devil_child]

you cap seals do go out...... Also do you see any hairline fractures on the endtanks. or even are there any gooey whiteish green deposites on the endtanks?

[byrdog24]

no sir,its real weird that i had an expansion plug go out on the manifold and thats when it started.it has gotten hot but don't think it blew the headgasket but not sure.when i went to parts house there were two kinds of caps,one was regular and the other was pressure relief would it make a difference? thank you all for your input!

[evildky]

I believe they are all "pressure relief" basically at pressure they push extra fluid into the remote resivoir, coming out around the cap definitely a bad cap, lets hope once its sealed up with a good car you're able to hold the pressure and keep cool, be sure to top off the cooling system