ok i have a 94 z28 6-speed. When i bought the car it was overheating bad. after tons of stops on the way home. i deside to change the water pump, thermostat (160), radiator cap. so everything was great for a week. then it started to overheat. so add coolant and blead the system. it stop running hot. now i have to put coolant in it after 30 minute drive.
the low coolant light comes on, the overflow gets full, the radiator is about 1/4 qt low, the car stay low in temp, there is no smell of coolant in exhaust, the oil is water free, the plugs are water free.

so to night I desided to take the cap and the radiator cover off and look for a leak. I started the car, with cap off, overflow disconnected. i try to bleed the system, when i open the bleeder next to the thermostat housing neck the coolant goes down so i fill it up to top. when the flow becomes solid, i tighten. now i try the top bleeder and the radiator over flows, plus it will only come out in little squirts. is this normal? the car stayed at great temp(first line) what could be my problem? i have no idea where the coolant could be going..

oh when i put cap on it does become pressurized

 

make sure radiator is full and overflow tank is at the proper level.
close the system.
run the car to operating temp
Open t-stat bleeder screw until flow is continuous (as you've already done)
Let system pressurize again and open top bleeder screw until there is a steady flow. If the system is relieved of all pressure and there is still not a steady flow then close screw, open radiator cap (MAKE SURE SYSTEM HAS NO PRESSURE!) to make sure coolant is still at good levels.
Start engine up and let system pressurize again and open top bleeder screw. Repeat this process until you get a steady stream.

Have someone with you watching the temp guage at all times.

 

i just went out a try again now there is a steady flow. now if tomorrow the car does same thing with low coolant what does it mean?

 

you need to check the radiator for a few days afterwards even if your coolant temp remains the same. You can still have some air pockets that will appear only after the engine has been agitated a bit (driving around).
If you still loose coolant and your temp is not w/in its normal range then you need to find out where the coolant is going. If it isn't leaking externally then one popular symptom is a blown head gasket(s).

 

check the coolant lines that go to the back of the head, i had an issue with them earlier. also check your radiator for damage and any broken hoses. park the car for a while and note if you see any puddles. if you're saying that you're running out of coolant with in 30 minutes while driving, thats alot of coolant missing, if its not external...then its a headgasket.

 

If your overflow is filling up and never emptying back into the radiator, then your overflow hose most likely has a leak and needs to be replaced.

The bleeders only have to be open when filling it with coolant. no need to open them at any other time.

 

ok so i change the oil again no coolant in oil.. however i bleed the system until i could not put any more coolant it the system. drove it to work (35 minutes) the light came on, coolant low. when i got home filled it up again ran car for 40 minutes, no over heating, no leaking, next day coolant low. should i replace radiator and hoses. is there any other place the coolant can be going? or do i just need a headgasket?

 

Next step is to pressurize the radiator. You can get the "loaner" at Autozone. Be sure engine and coolant are cold before putting it on the radiator. Pump it up and see if the pressure falls. You can also check for leaks while it is pressurized.

 

so here is the update i replaced the raditor with new. i still have same problem low coolant some time.

 

Why did you replace the radiator? Did you do the recommended pressure test, and find a leak?

 

ok i did pressure test today no leaks, no loss of pressure. what now?

 

Keep in mind, the "LOW COOLANT" light on these cars are notorious for going off, even when you've got plenty of coolant. Mine is literally on all the time! When I bought the car, the light would come on and off as it pleased, so don't use the light as a guide, as it's inaccurate.

When you keep "topping up on coolant" how much are you putting in? These cars hold roughly 14 Liters of water or so, which is quite a bit. When I replaced my rad, and WP last year, I had to learn how to refill the cooling system in this car, it's not like your usual fill as the LT1 sits lower than the rad.

I put the front of my car in the air, topped up the rad, capped it, opened up bleeder screws and started the motor. Monitor your temp. guage. Once it gets about 1/2 way, your fans should come on to cool things off (this is normal operation.) If the temperature goes past 1/2 way, and keeps iincreasing, you've just not got enough water in there, and possible air.

Turn the motor off, open the rad cap (use several rags, as it's HOT) top up the rad again. Cap it, turn on the motor, repeat until the cooling system operates normally.

I've used this method several times in the past two years, and it's worked like a charm.

Good luck!

 

OK so this morning got up put the coolant level was fine. so I started the car with cap off. opened both bleeders, put in more water until both bleeders flowed with water/ coolant. then I closed both. Once the temp went to the 1/4 line i opened the bleeder on the neck, good solid flow. next i opened the bleeder closes to the cap and the flow would not go solid. little spays. what do you guys make of this? i try for 20 minutes.

 

Go through a couple of hot and cold cycles and check it again.

 

You only need to open the bleeders when you are filling with coolant.