Techniques how to bleed the E30 M30! HELP!

[Garageaholic]

I can’t, for the life of me, bleed this damn cooling system. What techniques should I use when filling/bleeding this?

Is there any specific orientation that the plumbing should be that connects to the heater core?

Once the engine gets up to temp, coolant starts spewing out of the overflow tank. I know there’s air in the system and its expanding, but I can’t bleed it out!

Please help! I'm so frustrated!

[Garageaholic]

Any E30-M30'ers on right now to help?

[E30/M30]

If you're using the face lift M20 header tank it can help to raise it up whilst you're filling/bleeding, brim it right to the top. Same can be said for other kinds of header tanks.

Check the condition of the seal/O-ring on the header cap.

Make sure the small bore hose from the top of your radiator isn't blocked(including the union it fixes onto at either end).

Assuming you have an E34 generation M30 and top rad hose, the hose that T's off the top rad hose goes to the bottom union of the heater, the hose thats about 3/4"-7/8" bore comming off your 'stat housing connects up to the top union of the heater. On mine i've T'd into this hose so i can connect up the header tank.



HTH

Andy

[E30/M30]

Oh, and squeezing the top hose as you fill/blead helps.

Crack open the blead bolt as you fill and if you've got the header tank high enough you should get some water out of it.

[JoeMadoo]

It took me about 5 seperate times of bleeding the system until I got it to stay around 180 degrees.

[Garageaholic]

My setup

Here is my setup

Here are a couple of tricks I'm going to try...

If I don't have heat, I'll feel the heater pipes (inside the car) and see if the heater core is bad. It shouldn't, however, prohibit proper cooling of the Car. Think about it as if you had deleted the heater core altogether.

I think i'm going to drive the car around just around the neighborhood. It could dislodge and re-organize the coolant within the system and open up some of those air bubbles.

For the record: WITH REGARD TO THE FIRST POST, I NEVER HAD THE CAP ON FOR EVEN 1 SECOND, SO THE SYSTEM WAS NEVER PRESSURIZED. Since the coolant was overflowing so rapidly from the reservior, I was afraid to close the cap due to bursting hoses...

Take a look at the pic and again, thanks for the help.

[Garageaholic]

Joe,

What method did you use? what techniques. Do you have aux fan? Where is your coolant tank located?

[E30/M30]

Once you start warming up the car the coolant will want to come out and it's normal, put the cap on and carry on bleading and warming up.

Keep an eye on the temps and wheather you're getting hot air out of the heater.

Once it get's to around 1/3-1/2 way on the temp guage make sure the bottom rad hose is getting warm/hot, this will show if your 'stat is opening.

[E30/M30]

BTW your hose lay out looks OK

[Garageaholic]

Great. Thanks for the help. I'll try it again in a few hours after I get back from work.

So the hose coming from the coolant reservior should go to the TOP heater core inlet, not the bottom.

[E30/M30]

So the hose coming from the coolant reservior should go to the TOP heater core inlet, not the bottom.

Thats the way i've got mine, not sure if it make any difference though TBH ??

[Sean]

Not M30 specific, but there should be a overflow hose on the overflow tank - so in worst case scenario (sp?), excess coolant will be expelled from the system.

So, you have nothing to worry about coolant coming out of the cap, that will happen sometimes.

[Garageaholic]

Oh yeah, I forgot about that. yeah, I hooked it up, just didn't include it in the diagram..

What's the poing of the Reservior Cap to keep pressure on the system then?! lol

[Sean]

Oh yeah, I forgot about that. yeah, I hooked it up, just didn't include it in the diagram..

What's the poing of the Reservior Cap to keep pressure on the system then?! lol

It does keep pressue in. I believe the overflow point is above the cap, so it has to reach a certain pressure or something - I'm not positive. But, take a look at your reservoir the next time your out you'll see what I mean.

[george graves]

Oh, and squeezing the top hose as you fill/blead helps.

That' all I need to do to mine.

BTW - use BMW coolant.