proper way to bleed cooling system?

[89325iturbo]

whats the best way to get the air out?

also my gas gauge doesnt read correctly anymore, and seems to move around with the engine revs.

[shiboujin]

fill, turn car on, idle, get to operating temp with the heat going full blast until it sucks down an ass load of coolant. Then cap off, drive, fill up, done.

[R&D man]

bleeding

I heard about drilling a small diameter hole in the thermostat in the top position to allow air to flow through

[89325iturbo]

The heater core is bypassed in my car.

[shiboujin]

The heater core is bypassed in my car.

weight savings? or you just got lazy? Either way, I wag my finger at you sir.

[Mossman]

when the car is hot loosen the hose clamp on the top radiator hose and slide a pick or small screw driver in between the rad. and the hose on the top side, just enough to get a spurt of coolant. That's always worked for me on systems with no bleed screw that seemed to have trapped air.

[89325iturbo]

My heater core was leaking.

[guzz81]

This setup is incredible. I use mine daily...

http://www.thetoolwarehouse.net/p-7382-uview-550000.aspx

[rThor432]

I heard about drilling a small diameter hole in the thermostat in the top position to allow air to flow through

This works very well, except I would not recommend it for a cold climate (like Canada). Might give some issues getting to temp, especially in the winter.

[Adrian_Visser]

This works very well, except I would not recommend it for a cold climate (like Canada). Might give some issues getting to temp, especially in the winter.

Do you think it'll make that much of a difference? I drilled a little hole in mine worked great for bleeding. We'll have to wait for the winter to see if I have warm up issues I guess.

[89325iturbo]

Is it suppose to bubble at all? I could take the cap off my m20 after driving. With this a short drive and it would be bubbling out if I take the cap off.

[jlevie]

The proper way to bleed the cooling system is:

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.

A small hole (1/8-3/16") in the thermostat will have a negligible affect on engine operation and will make filling the cooling system easier.

The heater core is bypassed in my car.

Don't loop the heater hoses, plug them. If you loop the hoses part of the coolant flow will bypass the radiator when the thermostat is open.

[89325iturbo]

Plug them with what?

[surebimmer]

There is no bleed screw on e36 swap cars, unless you use the 318i radiator with expansion tank built in.

[isolatos]

I have some advise to offer. I just replaced my M50 with a different one due to the car overheating. I spent so much time getting the coolant system right the second time, taking every precaution I could. I installed an aftermarket VDO guage and cant keep my eyes off it. I have a brand new M42 radiator, 16 inch electric fan(ran through a relay to a switch in the car, I used water wetter, Zerex G05 coolant and distilled water, New metal impeller water pump and low temp thermostat. I bled the system by jacking the car up as high as possible, filled the coolant, ran the car for 10 minutes-watching the temp like a hawk, then I let the car sit for a couple hours, filled the coolant, opened the bleeder screw, installed cap, and ran the car for a long time, held revs at 2k rpm for a while, closed the bleeder and I was good to go. My temp when driving in 80-90 degree temps sits at 185-190, if the temp gets higher I throw my fan on and it drops immediately.

DONT TRY TO GO CHEAP ON COOLING SYSTEMS-THE M50 IS VERY EASY TO OVERHEAT AND CRACK THE HEAD!!!!

I have not had any oil or coolant consumption with my new motor and that makes me happy!
My .02