Adding "LOW COOLANT" Gauge when not equipped!!

[Bonswa]

I think the title speaks for itself. I have done searches, but no one seems to have any interest in this.

My 01 530i does not have a coolant level sensor. At least i dont think it does. Correct me if i'm wrong, but it would be attached to the expansion tank, right? I've run out of coolant and overheated many times in the past and this light never came on.

Being that i just went through more headaches than the president of GM to replace my entire cooling system, i would like to add this feature to my car.

It seems like the expansion tank that comes with the level sensor is exactly the same as the one without the sensor. That should be a direct swap. However.... the wiring is where i'm lost.

I'm not 100% sure, but i would imagine that my dash is a one-type-fits-all dash that is generic for all models similar to mine. That being said, i would have to guess that the "Low Coolant" light is on there somewhere. Even if it isn't... worst case scenario, it could be wired to the low windshield fluid light (EASY), or to just a yellow LED added to the dash or something.

It should be as simple as running wire from the new expansion tank with the sensor to the dummy light in the back of the dash.

Does anyone have any experience with this or have any tips before digging into this.

I'll make sure to take plenty of pictures and do a writeup on it. I think it will be EXTREMELY beneficial for the guys who dont have this feature. It takes all the guesswork out of it. Instead of checking your coolant every week or so, you can have a light tell you when it's low.

Thanks.

[curt2128]

really good question? I would like to see where this thread go.

[fifthand]

What year is your car? I thought they went to a chime and safety shutdown in '01? If this is true, I'm sure you would need an ECM, harness, etc. However, I really like your "low washer fluid" idea. That seems like the easiest. You will always have washer fluid.........

[Bonswa]

its a 2001. if theres some type of safety shutdown or chime, it definately was overlooked when building my car.

I'm not going to fool with the ECM. If its something as simple as purchasing a harness to plug into one of the open sockets in the ECM container, then that's one thing.

I'm glad you like the Washer fluid idea. Mine is ALWAYS full. Actually. My washer fluid never worked since i purchased the car. I just made some adjustments to my front bumper two days ago and replaced the washer motor while i was down there and the wheel was off. Thats why the idea was fresh in my head.

The way i look at is like this.... If the low washer fluid light comes on... i have two options:
1) Washer fluid low (RARE)
2) Coolant low

If you're worried about pulling over for the wrong reason, like the washer fluid being low instead of coolant, then disconnect it from the washer fluid all together. When it's empty, you'll know, cuz it wont spray! That way, when that light comes on, you'll know for sure that your coolant is low.

Like i said though, i can probably run directly from the sensor to something else like just a yellow LED dummy light like the one below. I can add a label to it that says "LOW COOLANT" or something.

[Cyrix2k]

Your car doesn't have it? My '97 540i does...

[Bonswa]

Nope. Positive. I replaced the expansion tank twice already. No sensor.

[PJB]

I was always under the impression that the 530i had the sensor, as it's one of the "upmarket" versions of the 2001-2003 e39. If you wanted a sensor from 1996-2000 you had to get the V8; if you wanted a sensor from 2001-2003 I though you had to get the V8 or the more expensive I6. Weird. It almost insulted me when I changed the expansion tank on my 528 and I noted the depression for the sensor, it was like a slap in the face. I mean, at least make a different tank for us instead of teasing us!

Anyway, I'm still searching for a thread of a guy who swapped his cluster because it has something to do with this retrofit. Along the way I found this thread:

http://forums.bimmerforums.com/forum....php?t=1018219

It has some interesting points: the guy did the cluster retrofit and mentions the coolant switch.

Also, he has a 2001 530, like you Bonswa. Do you have the HI-OBC or LOW-OBC? I thought all 530s had the HI-OBC, in fact I thought all e39s after 2001 had the HI-OBC. Apparently not.

[HiFIVE]

I was always under the impression that the 530i had the sensor, as it's one of the "upmarket" versions of the 2001-2003 e39. If you wanted a sensor from 1996-2000 you had to get the V8; if you wanted a sensor from 2001-2003 I though you had to get the V8 or the more expensive I6. Weird. It almost insulted me when I changed the expansion tank on my 528 and I noted the depression for the sensor, it was like a slap in the face. I mean, at least make a different tank for us instead of teasing us!

Anyway, I'm still searching for a thread of a guy who swapped his cluster because it has something to do with this retrofit. Along the way I found this thread:

http://forums.bimmerforums.com/forum....php?t=1018219

It has some interesting points: the guy did the cluster retrofit and mentions the coolant switch.

Also, he has a 2001 530, like you Bonswa. Do you have the HI-OBC or LOW-OBC? I thought all 530s had the HI-OBC, in fact I thought all e39s after 2001 had the HI-OBC. Apparently not.

I too thought that ALL 530i models had the High OBC. If you (OP) really wanted to receive low coolant messages you could perform the same retrofit.

Not sure if this will help, but I posted the following here after completing the High OBC retrofit in my 02/00 528i. Another good thread on the topic is here.

HIGH CLUSTER RETROFIT ACCOMPLISHED! Everything works!

Finally, success!

I was able to code the cluster using the Conversion path within Autologic. The Fasten Seatbelts, Door open and other messages didn't show up until the LCM was coded. As indicated by those who have done the retrofit, I did have to code the IKE to English from German following the installation.

Please learn from my mistakes! If you intend to retrofit High OBC first find an independent shop with a recently updated Autologic. Discuss exactly what you intend to do with a technician and be sure they are capable of using the equipment. With this in place, order parts, install the harness, coolant level sensor and setup a temporary bridge between the I and K bus junctions (I used an alligator clip). DO NOT instal the new cluster or break the I/K bridge until your car is in the shop, ready to be coded. To be safe, I tested the entire car with Autologic's "Quick Test" PRIOR to any conversions. With the vehicle fully identified and tested I selected "Conversions" and on page two "Low to High OBC". Carefully follow the on screen instructions for coding the IKE and then go to "Coding" and code the EWS and LCM. I coded the IHKA module as well for good measure. With everything functioning properly I chose "ASSIGN" from the IKE section of Coding. I ran another "Quick Test" following completion and found no stored errors.

[Bonswa]

Thanks for all the guidance. I'm going to do some more research and try to do this without the full retrofit stated above. I'll definately post some type of DIY when i get it done.

Thanks for all the help

[weasel like]

After replacing my entire cooling system, my car is also rendered "warningless" for coolant levels. I'm not sure why the replacement OEM parts didn't include sensors, my indy is confused too. Side note, my washer level warning just started popping on... could this be what you were talking about? Better check on it huh? Doh.

[Gumbi4u]

That sensor IS there! The connector itself might be cut and a resister might be put on by a previous owner. A long shot but could be possible. There is no way the sensor is not equipped in that car. Look around the RIGHT (driver) headlight. That is the general area it might be taped to since thats where the wire is originally snaked down to the tank.

[Skwisgaar]

For what it's worth, my 98 says "CHECK COOLANT LEVEL" as soon as the float in the expansion tank has reached minimum (high OBC).

[Bonswa]

That sensor IS there! The connector itself might be cut and a resister might be put on by a previous owner. A long shot but could be possible. There is no way the sensor is not equipped in that car. Look around the RIGHT (driver) headlight. That is the general area it might be taped to since thats where the wire is originally snaked down to the tank.

Can you do me a HUGE favor and snap like 2 or three pics of the wiring from the tank itself to wherever.

I felt the bottom of the tank, i did feel what could be a female connction. it was on the far passangers side of the bottom of the tank. Sound right? I looked all over and found NOTHING that could plug into it. If i knew where the wiring went, then i could possibly find my dead end.

i dont know what the purpose would be of removing this feature, but i would like to add it back if that was the case.

[PJB]

^^^ The expansion tank does not have any connection. The tank has a depression in it. You know those contraptions at the zoo where you can go into a tunnel and stick your head into a chamber and you're head is kind of inside of the animal pen but still separated? It's like that. The tank has a tunnel the protrudes into it, the sensor goes into that tunnel, and the connection goes into the sensor. Expansion tanks don't come with the sensor installed, they're two separate parts, and since you changed your expansion tank, that's why the sensor is not there. It may have been on one of your old ones though...

[Bonswa]

I still have the old one. Neither have a sensor. Both have the "tunnel". So that brings me back to my original question. Where's the wires that went to it if I had one?

[Bonswa]

So, from what you're saying, i could purchase something similar to what i've linked below. I could install it into that "tunnel" in the expansion tank. Then i SHOULD be able to wire it to the factory wiring.

http://cgi.ebay.com/ebaymotors/BMW-Genuine-Coolant-Level-Sensor-E39-M5-Z8-Roadster_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2e l1247QQcategoryZ33602QQihZ022QQitemZ350112255948QQ rdZ1QQsspagenameZWD1V

If this sounds right, which i dont see why not, then help me out with some pics here.

being that i have NO unused wires in my engine bay, even around the driver side headlight, i have no clue where to start.

could someone do me a huge favor and snap a few pictures from the start of the wiring (sensor) to wherever it ends? dont waste too much time or take anything apart. just lift the hood. I just need some idea of where this wiring "COULD" be if it was there originally. I still dont believe it was ever there, but pictures would help tremendously!!!

I dont want to end up like this guys post did!!!
http://forums.bimmerforums.com/forum...coolant+sensor

Thanks

[Bonswa]

Bump for some pics!!!

[Bonswa]

C'mon, someone has to have nothing to do today. Dont you want to go outside in the great weather and take pictures of stuff? How about your coolant sensor wiring? that sounds like a great idea!!!

[fifthand]

I just went out to try and take some pictures for you. If I understand you correctly, there isn't much of a picture to give. the sensor wire disappears into the wiring harness "wrap". I don't know/see any clip or connector of any kind.

[Bonswa]

HMMM... alright it's a start. I'm gonna have to use CarQuest support or ShopKey5 or something to find out where the end of that wire is.

I'm thinking there should be some type of clip cuz GUMBI said something about the drivers side headlight.

[howejt]

Unless you have navigation, the 2001 I-6 E39s in the US market do not come with the high-OBC and thus no low coolant warning-- assuming I am understanding functionality of the low-OBC system correctly (only basic check system). High-OBC will have a two-line LCD message center for scrolling the warnings.

All 2002 and 2003 I-6s have the high-OBC as standard equipment.

I'm concerned about why your 530i has had so many overheating or coolant loss episodes. That is not normal!

[Bonswa]

I know. I thought the same thing. The more i read, the more i realize that it's not that abnormal for my cooling system to need replacing before 60k. Everything is new, so i wouldnt expect that anything will fail now, but it's still in the back of my mind now that its happened so much.

I dont have navigation. I know for SURE that my car never came with the "Low coolant" warning.

So.... I'm going to back up and punt like i originally planned. I'm going to figure out some type of retrofit using the factory level gauge and wiring it to a simple dummy light. I will probably get creative and label the light as well.

I'll post some pics when i get to it.

[PJB]

Unless you have navigation, the 2001 I-6 E39s in the US market do not come with the high-OBC and thus no low coolant warning-- assuming I am understanding functionality of the low-OBC system correctly (only basic check system). High-OBC will have a two-line LCD message center for scrolling the warnings.

All 2002 and 2003 I-6s have the high-OBC as standard equipment.

Finally an explanation as to why some 2001 I6 e39s have the LO-OBC and some have the HI-OBC. Thank you.

[chromius]

For some reason this doesn't make sense to me. Why would even a low-obc e39 not come with a low coolant level sensor. My old 1988 325e even had one.

Could it be possible someone removed it at some point? Maybe it was going off too often

[Bonswa]

Damn Americans!!!

We're going to have to leave this subject alone until i can get to those programs and see detailed wiring diagrams for my car. I'll be at the shop thursday or friday to install the new brake setup. While i'm there i'll get on Shopkey and check it out. It's gotta tell me something.

I'll keep in touch.