318ti.org forum - How to properly bleed cooling system

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- - How to properly bleed cooling system (http://www.318ti.org/forum/showthread.php?t=27983)

wolferj-RIP

09-03-2009 10:34 PM

How to properly bleed cooling system

Quote:

Originally Posted by cooljess76 (Post 243267)

There's a lot more to it than just removing the bleed screw and filling the expansion tank. This is why people have to go back and rebleed over and over.

Start by parking on an incline so the nose of the vehicle is angled upward. Air bubbles travel up. With a cool/running engine, turn the heater on full blast. By full blast, I mean turn the temp knob on the HVAC panel to full red and turn the fan all the way to the highest setting. This will allow coolant to circulate through the heater core. Now, pop the hood and remove the radiator fill cap and bleed screw. Slowly add coolant/water to the radiator expansion tank. Continue to fill until you see coolant exiting the bleed hole. You can assist the air bubbles by tapping on the top of the radiator and massaging the radiator hoses. Once you see a steady stream of coolant with no bubbles flowing out of the bleed hole, replace the bleed screw and fill cap. Drive around the block a few times, park on the same incline, let the engine cool and repeat the process 3 or 4 times.

Thanks!

713bmw318ti

11-23-2009 01:47 AM

Man my heater was not working for 3 years and I bled the cooling system today. All i got to say is the heater blows hot!!!!

pdxmotorhead

11-24-2009 07:08 AM

Redline water wetter. It helps! The chemical breaks the surface tension of the coolant and helps air pass through the system.

Dave

dgroebl

12-20-2009 09:07 PM

So what if your radiator is already filled to the cold line? In order to get coolant from my bleed screw I have to fill the over flow tank higher than the cold line on the tank. I have to almost completely top off the radiator in fact to get coolant from the bleed screw. Do I need to worry about over filling my cooling system?

cooljess76

12-20-2009 09:15 PM

Quote:

Originally Posted by dgroebl (Post 254948)

Nope, the fill cap has a built in relief, so the system will not/should not overpressurize.

dgroebl

12-20-2009 09:26 PM

So then should I eventually siphon some out to get it back down to the cold mark? Or just don't worry about it because it will take care of it's self?

cooljess76

12-20-2009 09:38 PM

it'll level itself out once you drive the vehicle.

dgroebl

12-20-2009 10:14 PM

Thanks. So that's basically what I did last weekend. Seamed like the heater was maybe only 80% of what it should be though. So now I'm doing it again. Its been about 20 minutes, heaters nice and hot, probably got about a quart of coolant on the floor, but the bubbles just keep trickling out! Every 20 seconds or so there's a few more. I'm starting to think head gasket! :eek:

bmvw	12-21-2009 01:25 AM

Why is there so much drama with the BMW cooling system. I have a 300,000 mile Toyota and I think I only checked the coolant once. Yet BMW (& I hear Benz also) one little plastic part breaks and $5000 engine.

dgroebl

12-21-2009 06:20 PM

I think cars always reflect the culture that they came from:

Japan = Memoirs of a Geisha vs. Germany = Femdom

pdxmotorhead

12-21-2009 06:23 PM

Interestingly enough, I've drained my TI several times to do work never jacked it up tilted it or any thing. Just filled it back up opened the bleed screw and it purges fine....
I always use water wetter.

I've probably just cursed myself... :)

Dave

William

04-06-2010 01:30 PM

Pressure in the morning

I flushed the cooling system and went through all the procedures listed above. My heat is so hot it will run you out of the car. My problem starts on day 2. After the car sits overnight there is tons of pressure built up. Car is hesistant to start. Remove bleed screw and cap. Pressure is relieved and car starts right up. Not quite sure what is going on, and I know I may have left out some details, but I need some direction.

cooljess76

04-06-2010 04:29 PM

Quote:

Originally Posted by William (Post 266452)

The radiator cap is supposed to have a built-in relief @ a certain pressure. I think it was 15-19psi, but don't quote me on that. I can't remember what it is off the top of my head, but excessive pressure is bad. It sounds like your expansion tank is not relieving itself, you should make sure you have the correct radiator cap. Might also be a good idea to do a cylinder leakdown test as cooling system overpressurization can be caused by a minor head gasket leak.

sleighty

04-07-2010 06:36 PM

i fixed one of the plastic cooling pipes a few months back, refilled and bled the system with no problems i get a nice hot heater when required and the engine sits at the middle of the temp gauge. However in the radiator reservoir its about half way full, if i fill it to the top and do around a fortnights driving and recheck its gone down to half full again. Could i still have a leak? Or is this level normal? Ive never wanted to let it get any lower than half full so im not sure if i goes any lower

cooljess76

04-07-2010 07:16 PM

Quote:

Originally Posted by sleighty (Post 266574)

You might still have a leak or perhaps a cracked radiator/expansion tank. The best way to find out is to use a radiator pressure test kit, pressurize the system to about 10psi and listen for leaks. Another thing, CirrusSR22 noticed that one of the plastic cooling pipes had a defective flange on it that wouldn't allow it to seal properly. Check this thread for more info on that:
http://www.318ti.org/forum/showthread.php?t=18066

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