* E46 Cooling Guide (Information w/parts list/bleeding) *

Originally Posted by Jimlong1

Hey guys I'm new to this so if I do anything I should not than please tell me!! Anyway I have an e46 318ci coupe (year 2000) and the coolant was leaking out of the hose connector on the side of the block. I replaced this with a new part from my BMW dealer and the leak stopped on the block, but I'm still loosing the coolant, I can't see any leaks visually but it's going somewhere , the car is not overheating and is blowing hot air so I don't think it's the head, I'd love some help, it's a 1.9 petrol in case anyone asks, thanks

What is "hose connector on the side of the block" Pics?

Checked oil for any milky contamination?

Originally Posted by sgoetz628

Reading your posts for the first time, Mango. Great stuff, great information. Thanks! I've had my '02 330 CiC for a little over ten years now and have decided it's time to do a little maintenance, meanwhile things are getting old and breaking and I don't want (also can't afford) a new one. Picked mine up in Munich and still have the German plate in the front.

Anyway, I just have a few questions for you. Sorry if they sound kind of amateurish but hey, I'm an amateur! Plan on doing as much of the maintenance myself, as possible, and want to get it right. The first time.

*Do you always recommend changing the radiator? Mine shows no signs of staining or weeping. In fact, with just a little effort over the years, my engine compartment looks almost brand new. Amazing.

*What part did you get from Amazon and why?

*Assuming bleeding the system comes at the end, after installing all these parts, do you then refill the radiator, then put the car up on ramps, then bleed? If so, is it okay to run the engine long enough to get it up on ramps? And then should it be cold again before bleeding?

Thanks for all the information you provide on this site,

Steve

My car had 157k miles on the clock and gave no "signs" of needed a new radiator. The temp gauge always stayed in the middle. I found the hidden OBC menu that shows the actual temp (in F) and discovered I was running higher than should be, but not enough to overheat. So I replaced as a PM as Mango and suggest. I could not believe what a difference it made running back at "normal" temp made. You can tell the engine is working better, more power than before especially at freeway speeds. You didn't say how many miles but I would replace along with the other parts recommended in this guide.
p.s. my radiator was not leaking but was caked in dirt. I can only image the internals.

Hey mate ya it's milky on the cap and traces on the dipstick, I lit the oil to check for water in it an it was fine, mate of mine is a mechanic and he said that that's common enough in the oil, don't have a pic but its a 90 degree pipe coming out of the block behind the oil filter has 3 hoses connected to it,

Mango, you've done the world well with this guide.


We thank you.

You are very welcome. Here to help where I can!

Originally Posted by E46@46

My car had 157k miles on the clock and gave no "signs" of needed a new radiator. The temp gauge always stayed in the middle. I found the hidden OBC menu that shows the actual temp (in F) and discovered I was running higher than should be, but not enough to overheat. So I replaced as a PM as Mango and suggest. I could not believe what a difference it made running back at "normal" temp made. You can tell the engine is working better, more power than before especially at freeway speeds. You didn't say how many miles but I would replace along with the other parts recommended in this guide.
p.s. my radiator was not leaking but was caked in dirt. I can only image the internals.

Yes, sir! My friend's 95 M3 has a date-stamped 2008 radiatior and because the coolant wasn't replaced properly, it had developed massive amounts of deposits that clogged the radiator. We flushed it out as best we could, but still not as good as replacing it. It seems to be working fine.

Gentleman I'm having issues trying to remove what appears to be the expansion tank cooling hose.
Any suggestions of how to safely remove these without damaging anything would greatly be appreciated. Also new member here

First issue is the the clips must be depressed completely which can be a difficult thing to accomplish while pulling on the hose in tight quarters.
Then pulling the hose off can be tough because they can be stuck on badly after years and years. Just gotta pull real hard.
And sometimes you'll break off the plastic hose because they turn brittle.

Awesome! Thank you so much I didn't see any clips, clearly it's very dirty lol.

Actually I think it's clips. Not sure exactly which location this is from the pic.
Can you clarify?

Thats the top view and a general replacement picture

Originally Posted by Stinger9

Actually I think it's clips. Not sure exactly which location this is from the pic.
Can you clarify?

Here is a wider view of the hoses.

Yeah, I get it now. Those rubber hoses are attached to the plastic pipes under the intake manifold. Nasty place to work on them. I believer the connectors here are the squeeze type that must be depressed all the way to remove. In BMW's infinite wisdom they have made them very easy to assemble but hard to remove without breaking things. The two squeeze tabs must be pushed in all the way before they release. And even then the hoses pull off hard after they age.
The big danger is you'll break the plastic pipe which will then necessitate removal of the intake manifold. That removal job has been described as one of the most hated tasks even by experienced e46 DIY'ers.


If indeed these are the squeeze tab types, best to try to get small needle nose pliers in there to break off the squeeze tab ring around the perimeter so they will not be holding the hose onto the plastic. You're not going to reuse the rubber hoses anyway. Then you'll be free to just wrestle off the hose. Your main goal is to preserve the plastic hose if at all possible.

Yea your absolutely right! I got the one off near the intake manifold and working on the bottom one by the expansion tank. Once I cleaned it up a bit, I observed the pins and unlocked them. Thank you so much for your assistance.

After having this car since 2005, I never really worked on it until now. Having a blast believe it or not with the DIY. Your info is greatly appreciated.

Thanks again

Originally Posted by Stinger9

Yeah, I get it now. Those rubber hoses are attached to the plastic pipes under the intake manifold. Nasty place to work on them. I believer the connectors here are the squeeze type that must be depressed all the way to remove. In BMW's infinite wisdom they have made them very easy to assemble but hard to remove without breaking things. The two squeeze tabs must be pushed in all the way before they release. And even then the hoses pull off hard after they age.
The big danger is you'll break the plastic pipe which will then necessitate removal of the intake manifold. That removal job has been described as one of the most hated tasks even by experienced e46 DIY'ers.


If indeed these are the squeeze tab types, best to try to get small needle nose pliers in there to break off the squeeze tab ring around the perimeter so they will not be holding the hose onto the plastic. You're not going to reuse the rubber hoses anyway. Then you'll be free to just wrestle off the hose. Your main goal is to preserve the plastic hose if at all possible.

Replaced the hose, went to the dealer to get it and I installed it just like you said. If you look at the photo, does it appear that the expansion tank is relatively close to the belt? Is my radiator out of place?

I don't have a photo memory of my car, but now that you mention it, the ET is pretty close to your PS pulley.
And it is possible that a rad can be installed incorrectly as it must slide into clips as it is lowered into place. If left out of these clips on this side, it could be possible to be mounted too far rearward.

Without reviewing your history, if you're close to doing a cooling system refresh, I'd sure be wanting to make sure that rad in mounted exactly as it should be.

Originally Posted by Stinger9

I don't have a photo memory of my car, but now that you mention it, the ET is pretty close to your PS pulley.
And it is possible that a rad can be installed incorrectly as it must slide into clips as it is lowered into place. If left out of these clips on this side, it could be possible to be mounted too far rearward.

Without reviewing your history, if you're close to doing a cooling system refresh, I'd sure be wanting to make sure that rad in mounted exactly as it should be.

It was! The radiator was not placed correctly and it seemed as if it was off track. I adjusted everything and now it sits correctly and the ET has approximately one inch place from the PS pulley.

I think im going to have to replace the upper hose as well since I was about to bleed the system and I have a minor leak there near the fan clucth. Its only upon pressure so Im assuming theres a gasket or o ring there and maybe it feel off. Going to wait for the vehicle to cool down and check it out or replace it but at least its not anything else.

Easy to get the hoses on wrong if you don't lube them. O-ring gets twisted and you're cooked. I love my silicone O-ring lube.
While you are at it, try to get a brass bleeder screw to make your life more foolproof.

All done!

My old hose was missing the o ring so I just decided to swap the entire upper radiator hose since the other hoses have been replaced as well. Now to bleed the system.

Looked around and it appears simple:

Top coolant off
Car on
91 degrees fan low
Adjust Bleed screw
White bumbles = steam
Radiator fluid = ready

Sounds about right gentleman ?