overflow tank boiling over??

[yert315]

not necessarily. I'm running the m20 bottle and have no issues with bleeding. The feed hose is longer than it should be and has an "s" bend in it so the flow isn't optimal. But I use the "blow through the pisser line" method (that sounds dirty) which works quite well.

[kylelauffer]

So as long as the overflow tank is higher than the radiator you should be OK?

no as long as the overflow is higher than the hose going from the overflow to the thermostat housing is gravity fed. it has to be higher than about the middle of the thermostat housing.

[1987E30project]

So as long as the overflow tank is higher than the radiator you should be OK?

[kylelauffer]

yes it was all air. i used the 535i overflow now so it has better gravity feed. because the late 3 series one was creating mass air bubbles. thanks again guys

[yert315]

called it

[weaksauce]

so earlier in the posts a guy posted a proper way to bleed a e28 535i. i took off the hose that goes from radiator to coolant resovoir. added another hose to the coolant resivoir. i put cap on the resivoir. blew a air hose threw the coolant resivoir hose in to the coolant tank to follow through to the radiator and held the hose coming off the radiator (the little one that goes to the overflow to begin with) hold it straight up in the air and watch for bubbles with water come out. put hose back to coolant resivoir. add water and try to hold tank as high as possible. and before this whole process i poured water in the coolant resivoir until it came out of the bleeder screw. without the engine on.

now this all worked for me. and i learned from this site. thanks everyone! im having fun with it now! http://www.mye28.com/viewtopic.php?t=58368

i have bled it countless times.

so it was air huh?

[kylelauffer]

so earlier in the posts a guy posted a proper way to bleed a e28 535i. i took off the hose that goes from radiator to coolant resovoir. added another hose to the coolant resivoir. i put cap on the resivoir. blew a air hose threw the coolant resivoir hose in to the coolant tank to follow through to the radiator and held the hose coming off the radiator (the little one that goes to the overflow to begin with) hold it straight up in the air and watch for bubbles with water come out. put hose back to coolant resivoir. add water and try to hold tank as high as possible. and before this whole process i poured water in the coolant resivoir until it came out of the bleeder screw. without the engine on.

now this all worked for me. and i learned from this site. thanks everyone! im having fun with it now! http://www.mye28.com/viewtopic.php?t=58368

[M-technik-3]

Coolant under pressure boils at a higher temperature than when non pressurized. So when it's open it's boiling at what altitude your at Lower it like when you start going higher into the atmosphere aka less pressure it boils faster.

Your blood will boil if you are exposed to the atmosphere at 68K feet.

While on discussion of properly bleed system where is your bleeder screw? For E36's I fill it then drive up on a set of wooden rampsget it warm and open the bleeder and then fill it some more and do this till it over flows.

Then back of and let cool down and check levels, if over filled I use a turkey baster to suck excess out of reservoir.

[jlevie]

The most common cause of the symptoms cited is air in the cooling system. If proper bleeding has been done with no relief, there's a good possibility that the cause of the air in the cooling system is from a leaking head gasket.

A simple check for that is to fully bleed the cooling system, drive the car for a bit (but don't let it overheat), and re-bleed. Release of more than a few bubbles then, or on a subsequent bleed, is evidence of a leaking head gasket.

FYI: the best way to bleed the cooling system is with a vacuum bleed/fill system.

[kylekrueger]

when you say "boiling over" do you mean the coolant itself is actually boiling or is it just over flowing

[browntown]

sure there isn't an obstruction in the radiator? If you're positive it has been bled completely and a new pressure cap is on, I'd start questioning the radiator itself. Might be worth taking to a radiator shop and having them check it. OR Flush it with water and see if you can force water through it with one of those prestone kits. Thankfully thermostat's are built to fail in the open position, but if you've never changed it, time to replace with a lower temp one.

[kylelauffer]

okay thank you m tech i will try that. but still what about even when the caps off?

[booostit]

Sounds like the cap is failing to maintain the proper pressure and causing the system to boil. Get the proper rated cap, they do go bad as they get older.

[M-technik-3]

Sounds like the cap is failing to maintain the proper pressure and causing the system to boil. Get the proper rated cap, they do go bad as they get older.

[yert315]

that's the best answer I can give you with the limited info you provided.