L28ET almost overheating every time I drive it

[o_alcha3]

so i have a 240Z with an l28et. the motor is pretty much stock just intake and exhaust. it used to go 3/4 of the way to hot on the temp sensor when i was pushing on it alot. one time it got to the H when i was really beating on it on the highway.

since then every time i drove it it get about 5/6 of the way to H but never more. And it bubbles into the overflow after i turn the car off. and now it happens with just normal driving after about 8 minutes. but it will idle forever and not get past half.

i did a leak down test at about 60psi and detecting nothing as far as a bad HG or warped head. there is no burning of coolant and nothing leaking. I also took out the thermostat, just to get rid of that variable. and it didn't help.

any suggestions........please?

[NSR_s30]

Maybe you got a bad thermostat? Perhaps the water pump is giving up on you? Is there enough coolant in the car?

[o_alcha3]

no thermostat, water pump is pumping water from what i see in the radiator cap, and there is full coolent grrrrr

im thinking maybe the radaitor or the coolent passage lines are all grimy? idk?

[evildky]

if it idles without overheating ans you're overheating on the highway it's almost definitely the radiator, might be flowing just not enough to get all the heat out

[o_alcha3]

i think ur right. i cleaned the radiator and so far no overheating but it is much colder out and i only drove it for 10 minutes

[Dozer]

Check the tension on your surpinteen belt. And look for hoses with kinks

[evildky]

Check the tension on your surpinteen belt.

lol, does anything but domestic's use serpentine belts?