The mark is labeled "Kalt", or when the engine is cold. The top of the float s/b level with the top of the filler hole.

Make sure that the float is not damaged - lift it up to see if it's still attached to the lower part of the float. If you can remove it completely, it's deteriorated, and the expansion tank is in danger of splitting open.

 

Thanks for that, looking all over the web for an answer to this one!

Just to confirm, when I remove the filler cap, the orange s/b level should be flush up against the rim of the filler hole (where I removed the cap)?

Right now mine is about half an inch higher than this:

 

No, it s/b level with the top of the hole. If you put a straightedge across the hole, the ball on the top of the float s/b just kissing the straightedge.

 

ahh thanks for that!

While asking silly questions, what does s/b stand for?

 

s/b = "should be"
(but when you get angry then it is "son of a b-tch"! hehe...).

 

lol

I'll go top up the coolant level now - its clearly low with the top of the "float stick" 2 inches below the hole.

Thanks for your help!!

 

But, there is only about a half a cup or less difference between slightly below the bottom of the neck and the top. I've never really known how much difference that makes. My float level seems to vary slightly from day to day or week to week and I just attribute it to outside temperature or atmospheric pressure.

 

I am driving to Vegas from LA today and its going to be hot outside so will top it off just to be safe.

If the coolant level was a "little" overfull would this be harmful?

 

if you are going to take the time to reply to a thread here, take the time to type out what it is that you are trying to convey please. Saves us all some headaches.

 

??? Everyone seems clear in their responses...

My $.02 - There is a min and max line, as long as it is between you are OK.

dave

 

Hi,

OK, car was parked for about 1.5 hours when I "topped off", only took a little bit of coolant.

I took some photos of how how it looks now, does this look correct?

I hope this helps someone else.

 

Your level looks a little high.

Here's a pic from my owner's manual and one I took of the radiator "instructions."

Hope this helps...

 

I have an interesting side note on this issue.
When I bought my V ate 535 earlier this year I did the usual obligatory checks and realised that my coolant was way overfull. The indicator stem was actually sticking out of the chamber to the max, close to 2".
I thought this can't be good as their's supposed to be some room for air to expand (I believe).

I was then left with the quandary of removing said excess coolant.
So I'm off to the local chemist and bought the largest syringe that was available. Girl (with a frown) asked me if I wanted a needle, I said nah, scool. The thing loked like a horse needle syringe. So I get home and start removing coolant up untill I can't get anymore out, about 80mls at most. At that stage the indicator stem hadn't moved. So then I cut about 6" of some garden irrigation piping and attach that to the syringe. I was then able to remove enough coolant to get the orange blob at the correct level, some 400ml + - later. car hasn't missed a beat since and the level has stayed as is.

To the OP, get yourself a large syringe. Easy as man.

 

I have an interesting side note on this issue.
When I bought my V ate 535 earlier this year I did the usual obligatory checks and realised that my coolant was way overfull. The indicator stem was actually sticking out of the chamber to the max, close to 2".
I thought this can't be good as their's supposed to be some room for air to expand (I believe).

I was then left with the quandary of removing said excess coolant.
So I'm off to the local chemist and bought the largest syringe that was available. Girl (with a frown) asked me if I wanted a needle, I said nah, scool. The thing loked like a horse needle syringe. So I get home and start removing coolant up untill I can't get anymore out, about 80mls at most. At that stage the indicator stem hadn't moved. So then I cut about 6" of some garden irrigation piping and attach that to the syringe. I was then able to remove enough coolant to get the orange blob at the correct level, some 400ml + - later. car hasn't missed a beat since and the level has stayed as is.

To the OP, get yourself a large syringe. Easy as man.

Eh, props for your hard work but way easier and cheaper to just use a turkey baster to remove 1 cup at a time, more or less.

 

1+,

Josh is right Turkey Baster $2 at hardware store.

BTW, Piston-broke is from Australia, the Aussies have a unique way to solve problems down under (j/k)...

 

And most of them involve beer . . .:rofl:

 

Today, someone asked what the proper position was for the coolant level bobber, and I was surprised that it wasn't listed in the bestlinks, so, I ran an e39-only title-only search for 'coolant level', which got me three pages of related questions.

Arbitrarily, I chose this thread as the "canonical" thread, for us to post future updates to, and to help others with the same question in the future:
> E39 (1997 - 2003) > Silly Question - How to check the coolant level?

- What is the proper coolant level bobber stick height (1) & what to do when your expansion tank coolant level sensor float bobber stick is MIA missing in action (1) & where to find leaks when the CHECK COOLANT LEVEL is lit on the instrument cluster (1) & where does the coolant level sensor cable go (1) & what is the o-ring size for the coolant level sensor (1) & what is the temperature of the coolant when the thermostat opens under normal conditions (1) & how to modify the cooling system expansion tank 2 bar cap to 1.2 bar to vent at a lower pressure (1) & how to retrofit a coolant level sensor to an E39 that doesn't have it (1) & what is the most often recommended coolant (1) & tricks for efficient flushing (1) bleeding (1) and a coolant refilling DIY (1) & some behr/hella cooling system autopsy photos (1)

*******> ********>*******>********>

	BMW_TIS_17-00-005_Draining_and_topping_coolant.pdf (215.4 KB, 352 views)
	BMW_TIS_17-00-039_Bleeding_cooling_system_and_checking_for_leaks.pdf (118.7 KB, 359 views)
	BMW_TIS_17-00_Instructions_for_working_on_cooling_system.pdf (168.8 KB, 253 views)
	Bleeding_the_bmw_cooling_system.pdf (2.78 MB, 363 views)

*******> ********>

 

For the record, here are some pictures of coolant levels which are too high ...

See also:
- What is the proper coolant level bobber stick height (1) & what to do when your expansion tank coolant level sensor float bobber stick is MIA missing in action (1) & where to find leaks when the CHECK COOLANT LEVEL is lit on the instrument cluster (1) & where does the coolant level sensor cable go (1) & what is the o-ring size for the coolant level sensor (1) & what is the temperature of the coolant when the thermostat opens under normal conditions (1) & how to modify the cooling system expansion tank 2 bar cap to 1.2 bar to vent at a lower pressure (1) & how to retrofit a coolant level sensor to an E39 that doesn't have it (1) & what is the most often recommended coolant (1) & tricks for efficient flushing (1) draining (1) bleeding (1) and coolant refilling (1) & users' behr/hella cooling system autopsy photos (1)

 

Saw a tilted bobber in the E46 forums today:
> E46 (1999 - 2006) > Antifreeze symbol keep coming on.

 

This is a nice post, from today...
> E39 (1997 - 2003) > My coolant fill - no issue at all. Old time trick I from my 635 days.

I posted this info in another thread but here you go. With engine COLD and OFF:

On the reservoir side, just lean down and look sideways, compare the reservoir markings with the tstat housing, and you will see that:

- The "Neck" of reservoir is at tstat housing's bleeder screw level (RED Arrows).

- The KALT mark is at the same level as the very bottom of the tstat housing (GREEN Arrows).

a. So if one fills above KALT, it will do the trick ---> coolant will flow out of the bleeder hole.
The idea is: the tstat housing needs to be completely filled with coolant. However, you will end up with coolant level above KALT. In my experience, this extra coolant will go to some air pocket some place in the vehicle and eventually settle down.

b. Option "b" is to fill to KALT, then stop. Get a tiny funnel and fill through the tstat bleeder hole, go slow as you don't want to spill/waste coolant. Then gently tighten the bleed screw.

Personally, I like option "b" better.

See also:
> E39 (1997 - 2003) > DIY: The trick on how to fill the M52, M54 coolant

 

This very detailed owner is on his third expansion tank in a very short time, so, the information here is useful to this thread ...
> E39 (1997 - 2003) > Will the next person who replaces his expansion tank please cut it open & compare?

Also as part of my theory I wondered whether we'd got too much coolant in. When it was running previously the bobber was at the top and lightly kept on the stop by the coolant level, so maybe a tad over full?

 

I would like to ressurect this thread and add one more stupid question. I have a tansparent expansion tank. Am I also supposed to have a bobber level indicator stick? Because I don't. But while filling you can clearly see the KALT line. So maybe in 97 BMW thought it wasn't needed?? Or mine gave the ghost.

 

For you cold-weather fans, a thread was opened today specifically on checking the coolant level in the winter ...
> E39 (1997 - 2003) > how do you check coolant level when ambient temperature is 30F

 

I wonder if a lot of expansion tank leaks would be prevented if we didn't overfill them?

> E39 (1997 - 2003) > Leaking coolant from the expansion tank cap

Tnxs bluebee. The bobber is a really good point. I always top it off until the bobber sticks out a lot. I was confused or didn't realized that it should just be flushed on the next of the expansion tank.

I'll check again & I hope the Indy who replaced my expansion tank didn't get a defective one.

Or, would they leak anyway?

 

Someone with the Zionsville asked the question today, which may have a different answer, so I reference it here ...
> E39 (1997 - 2003) > Expansion tank level

 

I always have my red stick a little above reg level, never had an issue (only when my bleeder screw broke off, but since then i've replaced it), or over heat issue, and I never replaced the radiator since i bought the car this year... 210k miles

ill be buying a new temp coolant sensor since im getting P1112 and I know its the sensor because the two silver wires are broken... go figure...

 

There is a good thread on the coolant level height when the fluid fills the expansion tank, yet the bobber doesn't bob to where it belongs.
> E39 (1997 - 2003) > Coolant: proper level

All, see attached photos and you will understand my confusion. The expansion tank is nearly full: the coolant is near the filler neck, and yet the float is not up to the top of the neck. The float does not appear to be obstructed...I could push it down and it pops back up.

Clearly, I am at odds. I don't want to overfill the expansion tank and risk increased pressure, but nor do I want to underfill it either.

Ideas here? Is there something wrong with the float? To be on the safe side should I remove some coolant until I get this figured out?

Note: car has sat for 48 hours before this measurement.

 

Here's a good picture today for the proper bobber level
> E39 (1997 - 2003) > Coolant: proper level

This is the correct coolant level when the engine is cold e.g. after it has sat overnight on a level surface and you check the coolant level in the morning. This is a pic from my X5 E53- same coolant level check procedure as for the E39.

 

To help with the one-stop shopping, here's another good picture from that thread.
Notice that the specified max height is higher than what we're used to.

 

Every time someone reports their lousy expansion tank cracked, I ask them to snap a picture of the bobber level ...

Invariably, it looks something like this...

 

This thread was opened today...
> E39 (1997 - 2003) > Min/Maz Coolant Level

Interesting post. Just last week my "check coolant level" message came on. So I purchased a bottle of distilled water after I checked my expansion tank. I felt pretty good when I heard the loud "hiss" of air when I began unscrewing the cap indicating the expansion tank vacuum was sound.

My 530i has an image etched into the radiator shroud showing the expansion tank float (sensor) level (flush) with the top of the expansion tank. So I only filled it to that point. That left my expansion tank about halfway full.

 

This thread has just made a question pop into my head. I'm going to be doing a cooling system overhaul next week...my question is when I come to bleeding the system in order to get the air out of the bleeder on the expansion tank you need to fill right to the top....so when you finally have expelled all the air you are left with coolant right at the very top of the expansion tank.
Question is what to do.....just pop the cap on and be done with it or get a fluid extractor and remover enough to bring the float down to where it should be?

Ta
P