Coolant level rises with bleeder screw removal - E46Fanatics E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Go Back   E46Fanatics > E46 BMW > General E46 Forum

General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 02-13-2020, 10:55 PM   #1
darkfires102
Registered User
 
Join Date: Mar 2019
Location: Colorado, USA
Posts: 527
My Ride: 325xi, '07 E60 M5
Year: 2003
Transmission: 5spd Manual
Coolant level rises with bleeder screw removal

Opened my expansion tank to check coolant level and add water wetter, car was lukewarm after sitting for ~2 hours in the garage, small hiss. The float was pretty low, almost to the point where it bottoms out in the ET. Well, I figured to do the coolant bleed procedure topping it off, so I took off the bleeder screw, and immediately air rushed in and the expansion tank float rose all the way to MAX. Did I screw up? I ended up using a turkey baster to suck out some coolant to add the water wetter, and I ended up sucking out almost a full quart of coolant before the float dropped to below minimum! I guess im lucky that I checked the coolant level, I severely overfilled the ET, it luckily didnt blow up. Added the water wetter and some more coolant, I filled to midway between minimum and maximum...Nothing really came out the bleeder screw. Did I screw up removing the bleeder screw or is it OK? How do I know which one is the true coolant level? Screw or no screw on? Im gonna check the coolant level tomorrow when the car is stone cold, and drive it around, park it up, and check the level again with the screw on, and when its cold again. Mango...help?

Last edited by darkfires102; 02-13-2020 at 10:55 PM.
darkfires102 is offline   Reply With Quote
Old 02-14-2020, 04:10 AM   #2
Dennis325Ci
Registered User
 
Join Date: Sep 2018
Location: Europe
Posts: 108
My Ride: 2001 325Ci
Transmission: 5AT
The very same happened to me as well as I was finishing up my cooling system overhaul and bleeding procedure. The car was sitting for 24 hours by then I was about to re-check and adjust the coolant level. I opened the ET cap and the coolant (as I expected) was slightly low, then I cracked open the bleeder screw as well, not sure why I did that as you don't have to for a simply fill-up and level started to raise in the ET and went all the way up. It did not overflow, but was definitely at max. Then I let it run until it reached the operating temp of 96-97C and the level has been at max ever since. Still, I would be interested in what happened when I opened the bleeder screw. Because the level was slightly low at that point and I would have added some more coolant if I hadn't opened the bleeder screw.
Dennis325Ci is offline   Reply With Quote
Old 02-14-2020, 09:44 AM   #3
darkfires102
Registered User
 
Join Date: Mar 2019
Location: Colorado, USA
Posts: 527
My Ride: 325xi, '07 E60 M5
Year: 2003
Transmission: 5spd Manual
Quote:
Originally Posted by Dennis325Ci View Post
The very same happened to me as well as I was finishing up my cooling system overhaul and bleeding procedure. The car was sitting for 24 hours by then I was about to re-check and adjust the coolant level. I opened the ET cap and the coolant (as I expected) was slightly low, then I cracked open the bleeder screw as well, not sure why I did that as you don't have to for a simply fill-up and level started to raise in the ET and went all the way up. It did not overflow, but was definitely at max. Then I let it run until it reached the operating temp of 96-97C and the level has been at max ever since. Still, I would be interested in what happened when I opened the bleeder screw. Because the level was slightly low at that point and I would have added some more coolant if I hadn't opened the bleeder screw.
Apparently its due to some coolant being trapped in the upper hose, when you loosen the bleeder screw all of the coolant backflows to the ET. Im just afraid of overfilling and causing the ET to explode. Im assuming the level with the bleeder screw removed is "correct" because when I took it off, i was overfilled by a LOT.
darkfires102 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 02-14-2020, 09:54 AM   #4
lllRazorlll
Registered User
 
Join Date: Jul 2012
Location: Philadelphia, PA
Posts: 3,124
My Ride: Accord Coupe
Quote:
Originally Posted by darkfires102 View Post
Apparently its due to some coolant being trapped in the upper hose, when you loosen the bleeder screw all of the coolant backflows to the ET. Im just afraid of overfilling and causing the ET to explode. Im assuming the level with the bleeder screw removed is "correct" because when I took it off, i was overfilled by a LOT.
What he said.

This is the correct coolant bleeding procedure:



Also, it would be a good idea to get some tubing or a fitting to add to the expansion tank bleeder hole to siphon the coolant back into the expansion tank to avoid wasting any
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

lllRazorlll is offline   Reply With Quote
Old 02-14-2020, 10:54 AM   #5
bonestockE36
Registered User
 
Join Date: Nov 2019
Location: 2close2Chicago
Posts: 106
My Ride: 2002 330i auto
The bleeder screw is to be closed while the engine is running after being bled. You let air in by opening it while not running.

The system is self bleeding to a very small degree. Don't play with the bleeder once you've bled it, unless you are actually bleeding it.

I fill the system as much as possible. Start the car, and keep filling, rev it a bit to get air out, but not so fast that coolant is spilling all over. Once I don't see bubbles from the bleeder I close it. at that point I rev the engine and watch the flow from the bleed hole in the expansion tank filler neck. Once this flow has stopped producing bubbles I fill ET level and put on the cap. At this point it's ready to drive, but will absolutely need a few ounces topping up after a full cool down if it got hot during this time. This is why you run the heater full, to keep the engine cool and avoid expanding the coolant too much especially with later models with tiny ET min/max volume. That little hole in the ET neck is sealed by the cap to a check valve which bleeds bubbles and coolant into the top of the ET when RPM is high(the limited self bleeding system). This bleeding method worked in E36 and the first time I did E46 after engine swap, minimal cool waste, no turkey baster required, never rebleed, just top up the next time it cools down after reach operating temp.

However, to speed things up and keep things clean I use this method. Not my video, but someone who came up with the same process. Ive been doing this for years.

bonestockE36 is offline   Reply With Quote
Old 02-14-2020, 11:38 AM   #6
docnabimmer
Registered User
 
Join Date: May 2009
Location: NJ GSP 145
Posts: 334
My Ride: 2004 325XIT
Year: 2004
Model: 325XIT
Transmission: standard
What an awesome idea!!!thank you , less waste and less messy, what size hose is that? will do this from now on...
docnabimmer is offline   Reply With Quote
Old 02-14-2020, 03:27 PM   #7
Sapote
Registered User
 
Join Date: Jan 2008
Location: southern California
Posts: 2,889
My Ride: 2000 323i auto wagon
Quote:
Originally Posted by darkfires102 View Post
I ended up sucking out almost a full quart of coolant before the float dropped to below minimum! I guess im lucky that I checked the coolant level, I severely overfilled the ET, it luckily didnt blow up.
No, it wasn't over filled to begin with, and now it is way low in coolant. You should not open the bleeder when top off the tank. Now it needs a complete bleeding or it will overheated.
Sapote is offline   Reply With Quote
Old 02-14-2020, 03:41 PM   #8
jmo69
Registered User
 
Join Date: Mar 2013
Location: Wisconsin
Posts: 5,567
My Ride: 03 325xi 98 328is
Simple, if you are low on coolant, top off with just the cap off, leave the bleed screw alone. Simple as that.
__________________
Alternative to expensive xi control arm bushings
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


Bad outer xi ball joint?
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

2003 325xi auto Stahlgrau

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

1998 328is 5sp
jmo69 is offline   Reply With Quote
Old 02-15-2020, 01:23 PM   #9
LeverThis
Registered User
 
Join Date: Jul 2016
Location: SF Bay Area, CA
Posts: 1,480
My Ride: 2004 325i automagic
Quote:
Originally Posted by bonestockE36 View Post
The bleeder screw is to be closed while the engine is running after being bled. You let air in by opening it while not running.

The system is self bleeding to a very small degree. Don't play with the bleeder once you've bled it, unless you are actually bleeding it.
This confirms that the OP's cooling system is airtight, right? Coolant contracts as it cools down so the fact that air rushed in through the bleeder screw means it wasn't getting in elsewhere. Pretty sure that some have asked about partially collapsed upper rad hoses when the car is cold.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
:

20mm OD x 12mm ID x 4mm W : Viton O-Ring
3/4" OD x 1/2"ID x 1/16" Thick : Thrust Bearing/Washer

Last edited by LeverThis; 02-15-2020 at 01:24 PM.
LeverThis is offline   Reply With Quote
Old 02-15-2020, 02:10 PM   #10
Dennis325Ci
Registered User
 
Join Date: Sep 2018
Location: Europe
Posts: 108
My Ride: 2001 325Ci
Transmission: 5AT
Quote:
Originally Posted by darkfires102 View Post
Apparently its due to some coolant being trapped in the upper hose, when you loosen the bleeder screw all of the coolant backflows to the ET. Im just afraid of overfilling and causing the ET to explode. Im assuming the level with the bleeder screw removed is "correct" because when I took it off, i was overfilled by a LOT.
Yeah, I think mine was also overfilled after all. The 1.4 bar cap definitely let some pressure out as I had to wipe it clean. I have since removed coolant and set the level halfway between MIN and MAX on the float, so it has space to expand. Did not touch the bleeder screw.
Dennis325Ci is offline   Reply With Quote
Old 02-15-2020, 02:39 PM   #11
darkfires102
Registered User
 
Join Date: Mar 2019
Location: Colorado, USA
Posts: 527
My Ride: 325xi, '07 E60 M5
Year: 2003
Transmission: 5spd Manual
Just an update: coolant light on, i took out too much coolant, was at minimum level. Let out quite a bit of air taking the cap off, no severe air bubbles that are causing overheating though, used the OBC function and its at a firm 95-100c
Gonna monitor it for the next few days before I head out in the mornings and top off / release air as needed. Not touching the bleeder screw anymore

Last edited by darkfires102; 02-15-2020 at 02:47 PM.
darkfires102 is offline   Reply With Quote
Old 02-15-2020, 04:49 PM   #12
bonestockE36
Registered User
 
Join Date: Nov 2019
Location: 2close2Chicago
Posts: 106
My Ride: 2002 330i auto
Quote:
Originally Posted by LeverThis View Post
This confirms that the OP's cooling system is airtight, right?
No, the air that rushed in displaced coolant which migrated to "fill" the expansion tank. Per the post above after he removed coolant and the system self bleed, it's low on coolant.

If the vacuum relief valve in the cap was bad, you would see sucked in hoses when cold. This is an unlikely failure.
bonestockE36 is offline   Reply With Quote
Old 02-15-2020, 04:51 PM   #13
darkfires102
Registered User
 
Join Date: Mar 2019
Location: Colorado, USA
Posts: 527
My Ride: 325xi, '07 E60 M5
Year: 2003
Transmission: 5spd Manual
Sort of screwed...Coolant light wont go out after I filled to the MAX this morning. Assuming the level dropped a tad after starting the engine? Not sure on what to do now. The temperature is fine, the light just wont go out.
darkfires102 is offline   Reply With Quote
Old 02-15-2020, 04:59 PM   #14
bonestockE36
Registered User
 
Join Date: Nov 2019
Location: 2close2Chicago
Posts: 106
My Ride: 2002 330i auto
If the level was fine before you opened the bleeder screw and you took out a quart, that quart needs to go back in.

Don't worry about "letting air out" the cap takes care of this. It's your job to make sure coolant level is correct. It' not rocket science, but these forums make it out to be.

If coolant is disappearing, you have a different issue.
bonestockE36 is offline   Reply With Quote
Old 02-15-2020, 05:52 PM   #15
LeverThis
Registered User
 
Join Date: Jul 2016
Location: SF Bay Area, CA
Posts: 1,480
My Ride: 2004 325i automagic
Quote:
Originally Posted by darkfires102 View Post
Sort of screwed...Coolant light wont go out after I filled to the MAX this morning. Assuming the level dropped a tad after starting the engine? Not sure on what to do now. The temperature is fine, the light just wont go out.
Redo the bleed procedure in order to get the level correct and be sure to get rid of air all pockets. Make sure the front is raised or parked facing uphill. Not sure that you can get rid of all that air introduced thruough bleed screw by simply adding coolant to the ET itself.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
:

20mm OD x 12mm ID x 4mm W : Viton O-Ring
3/4" OD x 1/2"ID x 1/16" Thick : Thrust Bearing/Washer

Last edited by LeverThis; 02-15-2020 at 05:54 PM.
LeverThis is offline   Reply With Quote
Old 02-15-2020, 05:53 PM   #16
darkfires102
Registered User
 
Join Date: Mar 2019
Location: Colorado, USA
Posts: 527
My Ride: 325xi, '07 E60 M5
Year: 2003
Transmission: 5spd Manual
Quote:
Originally Posted by LeverThis View Post
Quote:
Originally Posted by darkfires102 View Post
Sort of screwed...Coolant light wont go out after I filled to the MAX this morning. Assuming the level dropped a tad after starting the engine? Not sure on what to do now. The temperature is fine, the light just wont go out.
Redo the bleed procedure in order to get the level correct and be sure to get rid of air all pockets. Make sure the front is raised or parked facing uphill.
On it now. Letting the car sit outside to cool off. Crossing my fingers I can get the light out
darkfires102 is offline   Reply With Quote
Old 02-15-2020, 07:54 PM   #17
darkfires102
Registered User
 
Join Date: Mar 2019
Location: Colorado, USA
Posts: 527
My Ride: 325xi, '07 E60 M5
Year: 2003
Transmission: 5spd Manual
I bled the coolant, have a steady stream of coolant coming out the bleed screw, level is max, the low coolant light WILL NOT go out now...
darkfires102 is offline   Reply With Quote
Old 02-16-2020, 04:06 AM   #18
LeverThis
Registered User
 
Join Date: Jul 2016
Location: SF Bay Area, CA
Posts: 1,480
My Ride: 2004 325i automagic
Quote:
Originally Posted by darkfires102 View Post
I bled the coolant, have a steady stream of coolant coming out the bleed screw, level is max, the low coolant light WILL NOT go out now...
If float shows max, then its not stuck in a low position ... try removing and unplugging the level sensor from the bottom of the ET and swapping it with the level sensor from the window washer fluid tank to see if that will work. They are the same sensor.

Maybe the level sensor just happened to go bad coincidentally? Coolant got in the electrical connector and caused issues or corrosion?
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
:

20mm OD x 12mm ID x 4mm W : Viton O-Ring
3/4" OD x 1/2"ID x 1/16" Thick : Thrust Bearing/Washer

Last edited by LeverThis; 02-16-2020 at 04:08 AM.
LeverThis is offline   Reply With Quote
Old 02-16-2020, 04:07 AM   #19
darkfires102
Registered User
 
Join Date: Mar 2019
Location: Colorado, USA
Posts: 527
My Ride: 325xi, '07 E60 M5
Year: 2003
Transmission: 5spd Manual
Quote:
Originally Posted by LeverThis View Post
Quote:
Originally Posted by darkfires102 View Post
I bled the coolant, have a steady stream of coolant coming out the bleed screw, level is max, the low coolant light WILL NOT go out now...
If float shows max, then its not stuck in a low position ... maybe try removing and unplugging the level sensor from the bottom of the ET and swapping it with the level sensor from the window washer fluid tank to see if that will work. They are the same sensor.

Maybe the level sensor just happened to go bad? Maybe coolant got in the electrical connector and caused issues or corrossion?
I got it now. I bled the coolant a little more and finally the light went out. Learnee my lesson for sure! Never open the bleeeer after its fully bled. Will monitor for the next few days.
darkfires102 is offline   Reply With Quote
Old 02-16-2020, 01:38 PM   #20
LeverThis
Registered User
 
Join Date: Jul 2016
Location: SF Bay Area, CA
Posts: 1,480
My Ride: 2004 325i automagic
Quote:
Originally Posted by darkfires102 View Post
I got it now. I bled the coolant a little more and finally the light went out. Learnee my lesson for sure! Never open the bleeeer after its fully bled. Will monitor for the next few days.
Nice ... tricky little things to bleed these engine are ... just tricky enough to be a hassle sometimes.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
:

20mm OD x 12mm ID x 4mm W : Viton O-Ring
3/4" OD x 1/2"ID x 1/16" Thick : Thrust Bearing/Washer
LeverThis is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON



All times are GMT -5. The time now is 08:45 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
(c) 1999 - VerticalScope Inc. All rights reserved.