bleeding the coolant system

[MIKe30]

ok, so i was just out bleeding my coolant system.... when running, my temp gauge goes up, and just keeps going up till i shut the car off.

so i figure i either a) need to bleed the system b) my tstat is fucked up, or c) that leaves my radiator.

b i think is out because when the car is running hot, the upper radiator hose is hot and from what i read that means the coolant is flowing and its probably not that.

so i'm bleeding it (up in the air on a jack), and its a lot of air coming out then a lot of coolant. so close the beeder screw. let the car cool down, took it for a drive. got really hot had to shut it off a few times and sit and wait on the way home, got it home and started bleeding it again.

this time a hell of a lot of steam is coming out, air and what not.... the heater is on full blast like recommended, its blowing out cool air. keep bleeding bleeding bleeding, and when i go to rev it all of a sudden its making these screeching noises?! i'm like wtf!? i know its been tinkering getting near the red mark when i've been driving it, but i've been shutting it off right before it gets there and parking it.


why is the car screeching now when i rev it? this ever happen to anybody else? i just shut the car off, closed the screw, and came inside.

[MIKe30]

anybody?


HELP I'M STRESSING!.

[E30andST185]

Where you just changing the fluid because it was old or did you change it in hopes of stoping it from overheating?

[Ablice]

Screeching noise?

Water pump.

How much coolant did you add to the system? You should have added it in two places: the radiator and the coolant resivior. You would add about half a gallon to either one, then add to the either one. All nice and slow to give the coolant time to find its way around.

The upper radiator hose could be full of hot air. Who knows. The thermostat can not be at fault because you said the upper radiator hose is hot. How's the coolant in the overflow tank?

[MIKe30]

Where you just changing the fluid because it was old or did you change it in hopes of stoping it from overheating?

no, i had a coolant leak in the hoses that connect to my throttle body. i bypassed it and connected them together this morning... i was running warm/hot before that because i keep running out/low on coolant because of the attrocious leak. now it's because of either air, my tstat, or my radiator.

just trying to bleed it properly so that i can see if that is the problem before i go ahead and jump to conclusions and pull my tstat.

Screeching noise?

Water pump.

How much coolant did you add to the system? You should have added it in two places: the radiator and the coolant resivior. You would add about half a gallon to either one, then add to the either one. All nice and slow to give the coolant time to find its way around.

The upper radiator hose could be full of hot air. Who knows. The thermostat can not be at fault because you said the upper radiator hose is hot. How's the coolant in the overflow tank?

the screeching stopped, i think it was because the bleeder screw was slightly open and the engine was HOT, so i think it was steam maybe just getting crazy?

the water pump is about 1000 miles old at most... so i'm pretty sure its not that.

i only added it in the resevior. i actually didnt know you could add it in two different places. is it possible that as i was bleeding when the engine was hot (by hot i mean above 3/4) it was steam coming out, that i was loosing a lot of coolant through the steam?

i ran out of coolant and will have to pick some more up tomorrow. this damn coolant shit is getting expensive quick.

[bmwtyler]

Ive never seen an e30 with a radiator cap. Sorry bud. Also, you should never bleed the system when hot.

[MIKe30]

Ive never seen an e30 with a radiator cap. Sorry bud. Also, you should never bleed the system when hot.

hmm... well then that kinda puts me in a bind then huh? cuz in a matter of a couple minutes my engine gets to 3/4 at idle due to bad fan clutch.


ooo do i love my e30

[deathray187]

The belt squeal was because it got wet.
You realize that you can partially bleed the system without the engine running right? I just flushed and bled my system this morning.(after replacing another MFing timing belt due to the tensioner bolt backing out) It's simple:

This is how I did it.
****WITH A COLD ENGINE*******
1. Make sure the drain is closed and all hoses are connected, double check everything.
2. Open bleeder screw(a lot, don't just crack it)
3. Add coolant and/or water to the overflow tank, it will suck up quite a bit at this point.
4. When it stops taking more coolant, squeeze the top radiator hose gently, it will help draw coolant into the system, add more coolant as room allows.
5. Once you cannot draw more into the system, make sure nothing is in the way of the fan and start the car.
6. Coolant and air will come out of the bleeder hole, this is normal, keep adding coolant until air bubbles stop coming out of the bleeder hole.(should only take about a minute tops.)
7. Tighten bleeder screw.
8. Turn engine off.
9. Make sure the reservoir is full, replace radiator cap, inspect the caps o-rings for good measure.

[MIKe30]

wish i read your post this morning... wouldve done it after i fixed my leak and before i read all the 'jack your car up, rev it bleed it rev it go for a ride repeat take two pills and call me in the morning' posts about bleeding the damn car.


thanks.



and wtf.

[hoyabmw]

It also sounds like your aux fan isn't coming on. On high speed, which should kick in before you get to 3/4, it should be able to pull the temp back down again quickly, even without the engine fan.

I pulled the engine fan off and put in an aftermarket fan hooked up to the a/c switch (no a/c either) and it has no problems keeping the temp at 1/2. On the highway I don't run the fan at all, and the car never gets near 1/2.

Bleed the system again--burp the hoses as described--and there really is no reason to jack the car up. Just bleed flat, and you have to get the car warm enough to open the thermostat in order to get coolant flow, but not overheating.

And unless you've got 3/4 water, 1/4 coolant, i doubt you need to buy more. Last time I refilled after draining the block, it took 1 gallon of coolant, and about 1.5 gal of distilled water. But then I don't drive it that much in the winter, so that mix is fine for me. You really want near 50/50.

Kevin

[MIKe30]

It also sounds like your aux fan isn't coming on. On high speed, which should kick in before you get to 3/4, it should be able to pull the temp back down again quickly, even without the engine fan.

I pulled the engine fan off and put in an aftermarket fan hooked up to the a/c switch (no a/c either) and it has no problems keeping the temp at 1/2. On the highway I don't run the fan at all, and the car never gets near 1/2.

Bleed the system again--burp the hoses as described--and there really is no reason to jack the car up. Just bleed flat, and you have to get the car warm enough to open the thermostat in order to get coolant flow, but not overheating.

And unless you've got 3/4 water, 1/4 coolant, i doubt you need to buy more. Last time I refilled after draining the block, it took 1 gallon of coolant, and about 1.5 gal of distilled water. But then I don't drive it that much in the winter, so that mix is fine for me. You really want near 50/50.

Kevin

my fan clutch is bad, and i think my aux fan is too. not 100% sure tho. still shouldnt be running hot when i'm moving because of those two.

[MIKe30]

The belt squeal was because it got wet.
You realize that you can partially bleed the system without the engine running right? I just flushed and bled my system this morning.(after replacing another MFing timing belt due to the tensioner bolt backing out) It's simple:

This is how I did it.
****WITH A COLD ENGINE*******
1. Make sure the drain is closed and all hoses are connected, double check everything.
2. Open bleeder screw(a lot, don't just crack it)
3. Add coolant and/or water to the overflow tank, it will suck up quite a bit at this point.
4. When it stops taking more coolant, squeeze the top radiator hose gently, it will help draw coolant into the system, add more coolant as room allows.
5. Once you cannot draw more into the system, make sure nothing is in the way of the fan and start the car.
6. Coolant and air will come out of the bleeder hole, this is normal, keep adding coolant until air bubbles stop coming out of the bleeder hole.(should only take about a minute tops.)
7. Tighten bleeder screw.
8. Turn engine off.
9. Make sure the reservoir is full, replace radiator cap, inspect the caps o-rings for good measure.

what did you mean by radiator cap? and where you adding coolant to the radiator, or the resevoir the whole time? i thought you could only add it to the resevoir.

[hoyabmw]

my fan clutch is bad, and i think my aux fan is too. not 100% sure tho. still shouldnt be running hot when i'm moving because of those two.

No, it shouldn't get hot if things are right, even without those 2. You don't have proper coolant flow, meaning you've got an air bubble somewhere. You need to redo the bleeding once the car cools down.

I have a good aux fan and fan clutch with fan $125 for both of them, shipped to you.

Kevin

[deathray187]

what did you mean by radiator cap? and where you adding coolant to the radiator, or the resevoir the whole time? i thought you could only add it to the resevoir.

Radiator overflow tank cap. And yes I am only adding through the overflow tank.

[Anhizer]

just a fyi- i bet the screeching noise you heard was a belt slipping because you got it wet when you were bleeding it. (or it leaked because the screw was loose and got on the belt)

[MIKe30]

No, it shouldn't get hot if things are right, even without those 2. You don't have proper coolant flow, meaning you've got an air bubble somewhere. You need to redo the bleeding once the car cools down.

I have a good aux fan and fan clutch with fan $125 for both of them, shipped to you.

Kevin

i redid it this morning and its still running hot. i am going to remove the tstat and see if that helps any.

and as far as those items i'll see what happens after i get my next paycheck.

Radiator overflow tank cap. And yes I am only adding through the overflow tank.

good. i was confused for a second there.

just a fyi- i bet the screeching noise you heard was a belt slipping because you got it wet when you were bleeding it. (or it leaked because the screw was loose and got on the belt)

i think so too. still freaked me out at the time because i think i can honestly still consider myself a car noob in the grand scheme of things.

[Ablice]

You're supposed to add it in two places. I would actually like to add it in a third place, but it won't let me.

Coolant flushing procedure:

(BTW M10 engines have no overflow tank)

1. Turn the key to the on position, not the accessory postion and turn the heater on max.
2. Using a catch pan, remove the lower radiator hose connection at the radiator connnection. Then when it's done, open the radiator drain petcock. Make sure you strip it too, those things are plastic. Then when that's done draining use a 19mm socket (3/4" can work also, but 19mm should work fine, if you use 3/4" use a six-point) and rachet. Open the block drain plug, on M20 engines is on the passenger side of the engine somewhere near #4 cylinder. With the B27 motors I believe it's better accessed (I did it a year ago on my 325e) from underneath the car, on B25 mills you can access it from the top. I don't know where it is on M10, M21, M30, M40 and M42 engine cars—I don't own those.
3. Now. With all the stuff buttoned up, remove the upper radiator hose at the thermostat connnection. (This is all M20 stuff) Loosening the radiator end makes thing easier. Then fill the hose with coolant until it won't take any more. Do it slowly—half a gallon at a time. While that coolant is finding its own way, fill the over flow tank. Don't bother removing the radiator end of the top radiator hose and try filling the head—it won't work. Snap everything up together (make sure to put the hose clamps so you can easily access the screws) and...
4. Fire the engine up. Go for a quick drive and then open the bleed screw. On M20 engined cars use a 8mm socket or combo wrench (preferably a six-point, also make sure you strip that bolt—if you strip it, you'll need a whole thermostat housing), on M40/M42 engines it's on the driver's side of the radiator. Make sure to strip that too—they're made of plastic so if you strip it you're in trouble.
5. Fill any additional coolant in the coolant tank. Seal up leaks and you're done. The fewer hoses you remove the better. Leave the heater on while you're bleeding it until you've fully bled the system through the bleed screw.

[MIKe30]

You're supposed to add it in two places. I would actually like to add it in a third place, but it won't let me.

Coolant flushing procedure:

(BTW M10 engines have no overflow tank)

1. Turn the key to the on position, not the accessory postion and turn the heater on max.
2. Using a catch pan, remove the lower radiator hose connection at the radiator connnection. Then when it's done, open the radiator drain petcock. Make sure you strip it too, those things are plastic. Then when that's done draining use a 19mm socket (3/4" can work also, but 19mm should work fine, if you use 3/4" use a six-point) and rachet. Open the block drain plug, on M20 engines is on the passenger side of the engine somewhere near #4 cylinder. With the B27 motors I believe it's better accessed (I did it a year ago on my 325e) from underneath the car, on B25 mills you can access it from the top. I don't know where it is on M10, M21, M30, M40 and M42 engine cars—I don't own those.
3. Now. With all the stuff buttoned up, remove the upper radiator hose at the thermostat connnection. (This is all M20 stuff) Loosening the radiator end makes thing easier. Then fill the hose with coolant until it won't take any more. Do it slowly—half a gallon at a time. While that coolant is finding its own way, fill the over flow tank. Don't bother removing the radiator end of the top radiator hose and try filling the head—it won't work. Snap everything up together (make sure to put the hose clamps so you can easily access the screws) and...
4. Fire the engine up. Go for a quick drive and then open the bleed screw. On M20 engined cars use a 8mm socket or combo wrench (preferably a six-point, also make sure you strip that bolt—if you strip it, you'll need a whole thermostat housing), on M40/M42 engines it's on the driver's side of the radiator. Make sure to strip that too—they're made of plastic so if you strip it you're in trouble.
5. Fill any additional coolant in the coolant tank. Seal up leaks and you're done. The fewer hoses you remove the better. Leave the heater on while you're bleeding it until you've fully bled the system through the bleed screw.

when you say make sure you strip it, cuz if you do your f'd, do you mean make sure you 'dont' strip it?

ok, i only added it through the overflow tank, and i bled it on and off from engine being off, then on and cold, then to operating temp.... revving it every now and then.... all throughout occasionally squeezing the upper radiator hose trying to get as much air out as possible. then when i thought it was satisfactory and overkill, closed the bleeder screw, and shut the car off, then retopped the overflow. just took it for a short drive and the bitch still overheats.

now i dont think that whatever little air is in there (if any but i'm sure there is no perfection in this 'bleeding' we all do) is going to have such a drastic effect and overheat the shit outta my car.

so i have decided to go ahead and pull the tstat and hope that it is just the problem. we shall soon see. (after the car cools of course )

but i have just one more question first. i find this akward about my car, and thought maybe all this bleeding the air out would take care of it, but does anyone else e30 do this: when i put the head on full blast, the temp guauge on the cluster goes up immediately by about a needle with. then eventually either stays there and does nothing, continues rising, or sometimes goes back down in temp.

any ideas?

[deathray187]

I think you might have other issues like a bad t-stat or something worse.

[MIKe30]

I think you might have other issues like a bad t-stat or something worse.

well if its not tstat, that just leaves radiator right?

[deathray187]

or a head gasket leak, or a water pump, or something else.
any brownish nastyness in your old coolant?

[MIKe30]

or a head gasket leak, or a water pump, or something else.
any brownish nastyness in your old coolant?

damn your scaring me. water pump is new. when i look in the resevoir its like a dirty green.... not like the vibrant glow in the dark green when i put it in.

[deathray187]

Do a compression check

[MIKe30]

great, another thing i dont know how to do. time to read and see if i have the tools. think they should all be about 160 though if i remember reading some threads about it, but i dont know how to get numbers.... so like i said i have to read.


i can already tell its going to be a great weekend.


oh and btw, thanks for stickin w/the thread and helpin me out. 'preciate it.

[thejlevie]

From reading all of this I rather suspect that there might be a head gasket leak that's pumping air into the cooling system. The most common cause of that is a prior overheat and it sounds like that may have happened one or more times from the throttle body coolant leak.

A qualitative check for a head gasket leak is release of air from the bleed screw over several bleed cycles. The definitive test is to pressurize each cylinder with 150-180psi for several minutes while monitoring coolant system pressure with a sensitive gage. A rise in cooling system pressure indicates a head gasket leak. A negative test on a cold engine must be repeated on a hot engine.