Well for starters my car is a Techno Violet 98 M3 coupe...my questions refer to my cooling system. The thing is I replaced my radiator and installed a brand new oem one, and used prestone fluid 50/50 premix. I started off with my engine cold and dry turned the heat on full blast and unscrewed the bleeder cap and let it get out all the bubbles. Ive done this numerous times and my car is still acting up.

Here are the symptoms its having

the temp. gauge flucuates from the 1/2 mark and back down to the 1/4 mark. It usually rides on the 1/4 mark when im driving, but if i start the car and let is warm up in place it will climb to the 1/2 mark which is normal temp as far as i know. I heard that the prestone coolant has phosphate in it so i am going to drain that asap, and I have already bought the bmw blue coolant to replace it. My climate control system shuts off and comes back on out of nowhere too..

Can anyone tell me the correct method of completely bleeding the system.

The low indicated temp probably means that the thermostat is bad. If the car has significant mileage (over 80k) replace the waterpump at the same time.

^yeah bad t-stat

i like the bleeding instructions over at www.understeer.com (end of waterpump guide).

That procedure is okay, but a better one that I've used for years on BMW's is below. A crucial difference is lifting the front of the car to encourage air to move to the front of the engine.

1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500 for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.

Thank you all for the helpful tips....A few people have told me that the thermostat might be bad, but others have told me that its just the air in the system. Can anyone be certain that its the t stat? The car is a 98 and has 56k miles only.

air in the system is going to cause overheats not underheating

so if air in the system would be causing an overheating issue which im not having whats my problem. What would cause the climate control system to just shut on and off like that for no reason. Its not the fuses those have been checked.

CC system problem might be a final stage unit malfunction which would be separate issue. Worry about that after you get the cooling system bled.

Lack of heat can be an air bubble in the system, which will migrate to the heater core, or a problem with the heater control valve. A proper full bleed (after you change the thermostat) will eliminate air in the heater core as a possibility. The heater valve is power on to close, so pulling connector will quickly isolate that to either the valve (valve stuck closed, blocked hose, plugged up heater core) or the Climate Control Unit. If you get heat with the valve disconnected the problme lies in the CCU. Otherwise you need to look to the valve itself.