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

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > Tuning & Tech > DIY: Do It Yourself

DIY: Do It Yourself
Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 01-12-2015, 02:20 AM   #1
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
Leaking Coolant Question

I'm new here, because I've just purchased a 330Ci - love the way the car handles! I'm having some coolant leakage - I've already read the threads about the usual suspects like the pump, tank, etc. and I've ordered all those parts so that I can do that project. My question is - are there other hoses that are not on the front of the engine that can leak coolant? My car leakage seems hard for me to understand. Wherever it leaks from, I can't see it. It doesn't always leak, but once in a while, after the car has sat and cooled I will look and there is a puddle. The car doesn't overheat and it never seems to leak more than a pint of fluid. This just seems strange to me - could this still be the pump, or are there hoses or other ways the car could be leaking that are not on the front (tank, radiator, hoses, etc.)???
Green6 is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 01-12-2015, 08:34 AM   #2
markusmarkus
Registered User
 
Join Date: Jul 2008
Location: USA
Posts: 1,993
My Ride: 2001 330Ci
There are 2 plastic coolant pipes that run UNDER the intake manifold. You could be leaking there. Cross your fingers as these pipes are a total PITA to properly install without leaks!!!

Also, see if a local gas station/mechanic will allow you to put the car on a lift with the engine idling. You'll have a better view of the "usual suspects." Just remove the under engine plastic cover!
markusmarkus is offline   Reply With Quote
Old 01-12-2015, 11:27 AM   #3
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
Just for the record, I did already have someone put the car on a lift and we removed the pan underneath so we could view the underside. No leaks appeared at the time. That's why I'm so baffled - it only leaks when you aren't watching!
Green6 is offline   Reply With Quote
Old 01-13-2015, 08:36 AM   #4
markusmarkus
Registered User
 
Join Date: Jul 2008
Location: USA
Posts: 1,993
My Ride: 2001 330Ci
Did you shut the engine off and then re-raise the car???
markusmarkus is offline   Reply With Quote
Old 01-13-2015, 10:10 AM   #5
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
No we didn't try that - probably should have!
Green6 is offline   Reply With Quote
Old 01-14-2015, 08:44 PM   #6
jjrichar
Modded ///Member
 
Join Date: Sep 2009
Location: Australia
Posts: 297
My Ride: 330 Ci convertible
I suspect there is nothing wrong with the car and the coolant is just leaking out of the coolant cap as per normal. Below is some information about the cooling system that might help.

As the coolant expands and contracts (engine running or not running) the system needs to take this into account. The cap on the expansion tap is two way pressure release valve. When you turn the engine off and allow it to cool, everything contracts. The valve on the cap allows air to enter the system and is a very soft spring that requires very little pressure differential to open. The more the system cools, the more air gets sucked into the system.

The two way valve that allows air to escape from the system requires about 2 bar of pressure to activate. It does this for a few reasons that aren't important to discuss here. So as the engine coolant warms it expands. Once the pressure increases to about 2 bar, the pressure release valve opens to keep the pressure inside at 2 bar. So as the car coolant continues to heat, it releases air out of the system until the temperature stabilizes at operating temperature. If you have too much coolant in the expansion tank, the coolant will expand and then come out of the cap. It will continue to come out until it gets to operating temp, and then it will stop.

Here's the problem (in my opinion). The indicator on the expansion tank for fluid level puts too much coolant in the system and causes it to come out of the cap when operating. People see a leak or see that the level looks low once it has cooled, and think it needs to be topped up. This causes the same thing to happen all over again. The problem is they can't find the leak.

I think the problem is that when cool, the correct level is lower than shown on the expansion tank indicator. The same thing happens on my 330Ci, my wife's Audi and my father in law's 545i. I have been chasing for ages a leak in my wife's Audi until I realised the leak was coming from the overflow of the expansion tank. I did a bunch of testing and found the equilibrium level of coolant so there was no leaking was actually lower than was recommended on the expansion tank. Once I stopped re-filling the tank, the leak stopped. In the Audi, the expansion tank is transparent, so you can see the level of fluid, and confirm that after a few drives the coolant level is no longer reducing. Obviously in the BMW you can't see this. Also, the expansion tank has multiple chambers. You may look down and see nothing, but it actually still has loads in it. The only thing that is actually telling you the coolant is low is the indicator in the instrument cluster. To test this (to have you rest easy it is going to work for you), drain about a litre of coolant from the outlet cock below the expansion tank to check the light comes on for you. Then just put it back in again.

Hope this helps

Last edited by jjrichar; 01-14-2015 at 08:48 PM.
jjrichar is offline   Reply With Quote
Old 01-14-2015, 10:13 PM   #7
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
Thanks both of you for commenting! jj - you might have a point, but if so, then why doesn't some evidence of coolant escaping around the cap show - wouldn't some fluid be visible around the cap at some point?

Also, a little off topic, when I jacked the car up to start draining the coolant, there is no evidence of either one of the drain plugs that are supposed to be there. I can see where the one for the radiator is supposed to be, but it's broken off way up inside (and very cleanly, too) - it barely looks like there is supposed to be a plug there at all. And the second one that all the tutorials mention (the one for the expansion tank) doesn't even seem to exist! I've looked everywhere so that it drives me crazy, but I don't see a second place for a drain plug. Any suggestions? (for either problem - how could I, if it's even possible, remove what remains of the radiator plug?).
Green6 is offline   Reply With Quote
Old 01-15-2015, 03:43 PM   #8
jjrichar
Modded ///Member
 
Join Date: Sep 2009
Location: Australia
Posts: 297
My Ride: 330 Ci convertible
Green 6, sorry I misread your post. I thought the leak was coming from around the top of the expansion tank. If is leaking from the cap, you will see coolant sitting on top of the expansion tank or the powder after it has evaporated.

The two coolant drain holes are at the bottom of the radiator and plug on the side of the engine block towards the front below the exhaust manifold. The one you have broken off is actually a long, funny shaped plug. It being broken is common when people installing don't know how it works. It's made of plastic with a couple of O rings around it that do the sealing. As you screw it up, the O rings push up inside and seal. It doesn't need to be tight. In fact it is sealed when it is about 5mm before it gets all the way up. The problem is that people think it needs to be tight to seal. It doesn't. It's fragile and is easily broken as you can see. Getting it out and replacing is going to be a PITA.

A leak should be easy to find as it leaves a powder residue once evaporated. If it's leaking after cooling down, you may want to remove the splash cover under the engine after you've stopped to see exactly where it's coming from. Your leak may be coming from this broken drain plug.

Last edited by jjrichar; 01-15-2015 at 03:47 PM.
jjrichar is offline   Reply With Quote
Old 01-16-2015, 02:50 AM   #9
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
Does anyone have any technique for removing the broken off drain plug? Or is there any alternative method to drain for the time? Can I drain the coolant from the engine block so that the coolant level will go down enough to replace the expansion tank? The radiator really doesn't need replaced yet.

NOTE: I just read in another thread that the new style Behr radiator has a new style plug. Is this why I'm having a hard time finding a BLUE plug? Maybe the new style looks different? Anyone have photos of a "new style" plug? I don't want to put a wrench to any of those plastic parts unless I know what they are.

I still can't find the leak - I did remove the splash cover under the engine, but it didn't really reveal where the leak was. It almost sounds like the pump might be getting ready to go because there is a squeaking sound in that area (maybe the pump bearings are bad?). But it seems to me that if the pump were bad, and leaking, then the coolant would be dripping down the front of the engine, and I can't see that happening.

Last edited by Green6; 01-16-2015 at 03:13 AM. Reason: New information
Green6 is offline   Reply With Quote
Old 02-07-2015, 06:10 PM   #10
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
Well, thanks to beberle I found the problem - the new style Behr radiators have a different drain plug, and my car doesn't have a drain plug for the ET. I'm sure others have this same set-up. I replaced the whole front and top cooling system, thanks to help from these forums. All the squeaks that you could hear from that part of the engine are gone!

Problem is there is still leaking. It follows a weird pattern. When I'm driving, there is no noticeable leaking. When I park the car long enough that it cools, I sometimes find a small puddle of coolant. This must be from some effect that takes place as the car cools, because there is no leaking at any other time. I will put about 8-10 oz. coolant back in the car and everything is fine until it sits and cools. Anyone have any theories on this?
Green6 is offline   Reply With Quote
Old 02-08-2015, 05:56 PM   #11
-lynel-
Registered User
 
Join Date: Feb 2014
Location: Brisbane, Australia
Posts: 236
My Ride: 2000 BMW 323i
I don't want to worry you but from what ive read you seem to have covered everything. if you start the car with the radiator cap off do you get steam or gasses coming up through the bleed hole in the expansion tank? or bubbles up from the bottom of the ET? excessive pressure can be built up by a seeping head gasket that forces fluid out when the engine heatsoaks when stopped. its not very common without other symptons like hard starting or knock as the coolant cavitates/ water hammers around the cooling system at startup. also you get like a slurping sucing noise from the engine bay when you trn the engine off
-lynel- is offline   Reply With Quote
Old 02-09-2015, 02:51 PM   #12
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
lynel - thanks for your time to reply! I have no symptoms of any type for any head gasket troubles. My impression is that one of the heater hoses has a pinhole leak that is aggravated when the engine cools. I was also wondering if there are any other ways for the cooling system to leak other than the hoses, etc. - as in, can the heater valve leak, or are there any hard lines that could leak somehow? I'm pretty sure this is only a cooling system leak. Who knows though, I might find different before I'm done.
Green6 is offline   Reply With Quote
Old 02-10-2015, 12:42 AM   #13
Jas01
Registered User
 
Join Date: Feb 2015
Location: Philippines
Posts: 16
My Ride: Honda
did you checked the drain plug? Also try checking the drain plug and see if it lost thread. Same thing happened to me years ago. When I couldn't find any leaks, the last thing I checked was the drain plug and to my surprise, the leak actually came from it. It is not a huge leak but is enough for the radiator to lose some coolant especially during long drive. I hope this can help..
__________________
Sports writer, old school car lover and F1 odds tipster.

Last edited by Jas01; 02-10-2015 at 12:47 AM.
Jas01 is offline   Reply With Quote
Old 02-10-2015, 01:22 AM   #14
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
I'm sure it's not the plug. I put the car on ramps, removed the splash guard and put paper under it hoping that it drips down and I can at least get an idea of where it's coming from.
Green6 is offline   Reply With Quote
Old 02-10-2015, 01:30 AM   #15
Jas01
Registered User
 
Join Date: Feb 2015
Location: Philippines
Posts: 16
My Ride: Honda
I see. Coolant leaks can really be hard to find. Also consider the radiator cap as one of the culprit. Happened to me as well. I have had a lot of issues with my radiator before and most of the time, it's the simplest things that makes the coolant leak.
Jas01 is offline   Reply With Quote
Old 02-10-2015, 02:37 AM   #16
Green6
Registered User
 
Join Date: Jan 2015
Location: Arizona
Posts: 10
My Ride: 2002 330Cic
lynel - if it were my head gasket wouldn't I at least have coolant in my oil or vica versa? If there was a problem with the head gasket wouldn't it manifest itself in other ways also? I just drained the coolant and no oil residue. No smoke from the car, start up is smooth and the car runs smooth with no power loss. No sign of coolant in the oil either. I will check with the ET open when I start it and see if anything happens. I don't notice any of the noises that you describe when starting the car or shutting it off.
Green6 is offline   Reply With Quote
Old 02-10-2015, 08:26 AM   #17
markusmarkus
Registered User
 
Join Date: Jul 2008
Location: USA
Posts: 1,993
My Ride: 2001 330Ci
The plastic bracket on which the expansion tank sits can go bad, especially if the ET has been replaced several times.
markusmarkus 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 07:42 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use