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

The coolant level sensor needs to be in the correct position, otherwise it will measure coolant incorrectly. Maybe it won't cause much trouble to hang it loosely, but as the BMW owner, it is a legally binding requirement to do things correctly

The sensor has a notch on it, and it should be a slot connected to the hole at the bottom of the coolent tank. If you can take a picture it would easier to explain. You need to match the notch with the slot and push all the way in. It is not tight, just gently push in then twist to lock it into place.

Originally Posted by Raymond42262

...I have seen other posts that said it could hang loose. But I don't believe everything I read, especially when it comes to short cuts.

There's no problem with this as long as you don't want it to work correctly. If you want it to work correctly, then it has to be correctly locked in.

Originally Posted by TonyJ

The coolant level sensor needs to be in the correct position, otherwise it will measure coolant incorrectly. Maybe it won't cause much trouble to hang it loosely, but as the BMW owner, it is a legally binding requirement to do things correctly

The sensor has a notch on it, and it should be a slot connected to the hole at the bottom of the coolent tank. If you can take a picture it would easier to explain. You need to match the notch with the slot and push all the way in. It is not tight, just gently push in then twist to lock it into place.

Originally Posted by joegr

There's no problem with this as long as you don't want it to work correctly. If you want it to work correctly, then it has to be correctly locked in.

I tried again.......another failure.

I tried rotating it in every direction but only one way works. I can get it in there, but it does not want to rotate. doggone it...
It sits in the bottom but it has not fallen out. I'll throw some duct tape on it until I figure it out. At least it will remain in position.

It might be going to an indy shop anyhow..............

New problem............I noticed that when I cut on the car that it whistles from the fan......it did not do that before. Please tell me it is just from sitting for 2 weeks and not because I have a bigger problem. ......please reassure me that the damage is limited to the expansion tank and nothing else. I have not driven it more than a few miles since I replaced the tank. The coolant level is where it should be, and it is not leaking.

Originally Posted by Raymond42262

It might be going to an indy shop anyhow..............

Dude, if you do this, you will have one less item on that list of proud accomplishments engraved on your tombstone...

I wouldn't. If it was me, I would drain the coolant, remove the tank again (since you've done it before and not too difficult), then try to figure out how to properly seat the sensor, under a magnifying glass...

Originally Posted by TonyJ

Dude, if you do this, you will have one less item on that list of proud accomplishments engraved on your tombstone...

I wouldn't. If it was me, I would drain the coolant, remove the tank again (since you've done it before and not too difficult), then try to figure out how to properly seat the sensor, under a magnifying glass...

good idea
i looked at the old one but i need to try this.
it does feel good when you got it all figured out.

I always attempt to dry fit parts before I start a job to check to see if the production might have changed.

Or really crappy manufacturing tolerances.

Originally Posted by Raymond42262

good idea
i looked at the old one but i need to try this.
it does feel good when you got it all figured out.

Maybe the new tank has a little flake of plastic in the way that should have been trimmed out?

Originally Posted by Stinger9

I always attempt to dry fit parts before I start a job to check to see if the production might have changed.

Or really crappy manufacturing tolerances.

I checked the hoses but not the sensor....

Originally Posted by joegr

Maybe the new tank has a little flake of plastic in the way that should have been trimmed out?

Originally Posted by Raymond42262

I checked the hoses but not the sensor....

We all gotta learn somewhere!

Firstly to GSherbs - we are not supposed to do any routine maintenance in our underground/under-apartment car parking bays (which we have to pay extra for...), here in Hong Kong - so naturally, one doesn't. On the other hand, Emergency repairs Are allowed - and it's astounding how many "emergency repairs' one can find to do on an old Triumph Tiger, Harley Sportster, BMW R1200C, Ducati Monster and Kawasaki Vulcan, before one bites the bullet and buys an old Beemer banger to play with...!

To the magnificent Mango - thanks for the comments on my first post, though I don't plan to dive straight into my cooling system just yet.
Then again, I have bought this Bavarian beast, knowing full well that "the heater doesn't work very well" (unquote), so I may well be taking your - very comprehensive - Cooling System Kit list of part numbers to the local BMW dealer in Kowloon - sooner than I would have hoped...! With only around 60,000 miles in your currency, I'm hoping to just do the more mundane stuff like oils & plugs, before delving deeper under that bonnet (sorry - that's the hood, for our colonial cousins...), though I'll now be having a very close look at the expansion tank for cracks/fluid level, then possibly starting her up from "cold" (that's a relative concept, over here...), and watching the temperature indication to see if we get the expected rise, then slight drop - as our thermostat opens.
If there is an actual heater problem, carrying out your "Refreshment" of the cooling system should establish a good baseline from which to start further fault diagnosis, and the mileage is about right for such a project. One reason for going from two to four wheels (apart from preferring air-conditioned, leather-covered luxury seating...), was to have another toy to play with whilst keeping these old fingers greasy - yet without disturbing anything that is running well. As an ancient English aircraft engineer for several decades used to say: "If it ain't f**ked, don't fix it...!" So I'll bear that in mind whilst happily getting to know some inner workings of this smooth old 6-pot.
Pictures may follow later, though it's a plain old silver 4-door saloon and nothing too special to look at. Until you take a peek under the skin, so to speak, and marvel at the clever toolkit (all intact...!), in the boot lid (sorry, trunk), and that magnificent motor in the front - with six little ignition coils, each sparking their own NGK Platinum plug (that's what I'll be installing, anyways...), plus even a dedicated power post for jump starting...!
Now I know why we buy BMW's.

Cheers guys - and apologies if I go on a little...!

Autolycus.

Originally Posted by Autolycus

Firstly to GSherbs - we are not supposed to do any routine maintenance in our underground/under-apartment car parking bays (which we have to pay extra for...), here in Hong Kong - so naturally, one doesn't. On the other hand, Emergency repairs Are allowed - and it's astounding how many "emergency repairs' one can find to do on an old Triumph Tiger, Harley Sportster, BMW R1200C, Ducati Monster and Kawasaki Vulcan, before one bites the bullet and buys an old Beemer banger to play with...!

To the magnificent Mango - thanks for the comments on my first post, though I don't plan to dive straight into my cooling system just yet.
Then again, I have bought this Bavarian beast, knowing full well that "the heater doesn't work very well" (unquote), so I may well be taking your - very comprehensive - Cooling System Kit list of part numbers to the local BMW dealer in Kowloon - sooner than I would have hoped...! With only around 60,000 miles in your currency, I'm hoping to just do the more mundane stuff like oils & plugs, before delving deeper under that bonnet (sorry - that's the hood, for our colonial cousins...), though I'll now be having a very close look at the expansion tank for cracks/fluid level, then possibly starting her up from "cold" (that's a relative concept, over here...), and watching the temperature indication to see if we get the expected rise, then slight drop - as our thermostat opens.
If there is an actual heater problem, carrying out your "Refreshment" of the cooling system should establish a good baseline from which to start further fault diagnosis, and the mileage is about right for such a project. One reason for going from two to four wheels (apart from preferring air-conditioned, leather-covered luxury seating...), was to have another toy to play with whilst keeping these old fingers greasy - yet without disturbing anything that is running well. As an ancient English aircraft engineer for several decades used to say: "If it ain't f**ked, don't fix it...!" So I'll bear that in mind whilst happily getting to know some inner workings of this smooth old 6-pot.
Pictures may follow later, though it's a plain old silver 4-door saloon and nothing too special to look at. Until you take a peek under the skin, so to speak, and marvel at the clever toolkit (all intact...!), in the boot lid (sorry, trunk), and that magnificent motor in the front - with six little ignition coils, each sparking their own NGK Platinum plug (that's what I'll be installing, anyways...), plus even a dedicated power post for jump starting...!
Now I know why we buy BMW's.

Cheers guys - and apologies if I go on a little...!

Autolycus.

Great 2nd post. Yes definitely get the stock NGK plugs. Still in for pics. The more stock the better again welcome to the forums.

Quick comment about the advice above to drain the ET to reseat the cooling level sensor...

Not necessary at all...the sensor sits in a dry part of the tank. No coolant will come out from sensor hole. It only rotates 90 degrees to get tight...iirc...maybe 180 degress...but it doesn't 'turn' a full rotation.

Originally Posted by dmax

Quick comment about the advice above to drain the ET to reseat the cooling level sensor...

Not necessary at all...the sensor sits in a dry part of the tank. No coolant will come out from sensor hole. It only rotates 90 degrees to get tight...iirc...maybe 180 degress...but it doesn't 'turn' a full rotation.

Good info. but someone already said that look a few posts above. the man with the magic coolant level sensor

Tell the guy who posted above me...and who I responded to. I'm sorry, but I can't keep up with every post in every thread...especially one as long as this one. Just trying to save the guy some time.

Yeap i switch mines from washer to ET and its 90 grades, its always dry and both are same!

Originally Posted by dmax

Quick comment about the advice above to drain the ET to reseat the cooling level sensor...

No one said you need to drain coolant the fit the sensor. I only said it because that poster seems to have no way to seat it properly. So I suggested to drain coolant, remove the tank, and try to figure out under a manifying glass. Did you read the context?

I have a new problem now...........

The engine temperature light stays in the middle zone now...it has not overheated since replacing the expansion tank. Good.

I have the temp sensor in the bottom of the expansion tank. I don't think it is seated properly but it has not fallen out... Good.

But the 'low coolant' light came on Saturday. I thought I had a slow leak from a hose that was improperly installed or I had done a poor job of seating the expansion tank. But the coolant level is full. I have not leaked any fluid since I topped it off, I bled the tank thru the screw. the floating level stick pops up when I remove the cap, there are no leaks on the ground.

The engine temp gauge does not go beyond the middle, I have not found any obstructions in the hoses and I don't think it has to do with the thermostat or the water pump because if it did, then there would either be smoke or condensation and the temp gauge would go up.

The engine seems to be idling fine, I don't have that whistling sound that I had before. I concluded that the whistle was a result of coolant dripping on the belts when I filled the expansion tank or from water that may have dripped on them when I wiped dirt off the engine block with a wet rag.

Is it a bad expansion tank.....is it possible that the floating stick thing is not doing its job properly ?

Is it possible that the ratio of water to coolant is too high ? I can't tell you with certainty what the ratio is. I have added coolant, water, coolant more water too many times. I lost count how many times I removed the hoses and lost water etc...

Any ideas ?

BTW, the car is parked again.........

did you replace the sensor and seat it correctly. maybe faulty sensor. as long as your car has the correct amount of coolant/water in it, you should be fine.

Originally Posted by E46Mango

did you replace the sensor and seat it correctly. maybe faulty sensor. as long as your car has the correct amount of coolant/water in it, you should be fine.

I did not replace the sensor.

It never occurred to me because it was outside the expansion tank.

Perhaps it was damaged when it was laying around the engine block while I was messing with the hoses ?

But why would a sensor that measures temperature that mounts outside the tank have anything to do with the fluid level inside the tank ? I could understand if there was a problem with the flotation stick.

But how does a temp sensor relate to water level inside the tank ?

Originally Posted by Raymond42262

I did not replace the sensor.

It never occurred to me because it was outside the expansion tank.

Perhaps it was damaged when it was laying around the engine block while I was messing with the hoses ?

But why would a sensor that measures temperature that mounts outside the tank have anything to do with the fluid level inside the tank ? I could understand if there was a problem with the flotation stick.

But how does a temp sensor relate to water level inside the tank ?

who said anything about a temp sensor