Anyone here successfully retrofit a Coolant LEVEL sensor?

Hi guys,

I forgot which year they introduced the Coolant LEVEL sensor (maybe 1999 or so) but my car does not have one. So I want to install it but reading some old posts, it seemed like people have problem installing it for a variety of reasons.

http://forums.bimmerforums.com/forum....php?t=1514945

http://forums.bimmerforums.com/forum....php?t=1101736

Just wondering anyone here successfully retrofit a Coolant LEVEL sensor?

I have the Low OBC, so this is my plan: I want to connect the Coolant Level Sensor into the "Low Windshield Washer Fluid" circuit as a practical solution.

It is kind of a "redneck engineering" but this allows me to see some warning such as "Low Windshield Washer Fluid", this warns me to open the hood and check for BOTH coolant and washer fluid levels anyway.

Anyone has tried it this way (tapping into the Windshield Washer Fluid sensor circuit)?

I tried to find a solution to this problem, i.e. the low cluster does not have a coolant level warning. I wanted to connnect a retrofit level sensor in the expansion tank, connect it to the LCM which was then supposed to control the (inactive) "low radiator" mask in my low cluster. I got lots of help in the bimmerforums/diagnostic forum, but failed. My last post follows.

*********************
I've hunted high & low for coding to implement the low coolant light in the low cluster. I've not even been able to confirm that it is feasible, i.e. that VDO/BMW implemented the feature. I'm conceding defeat on this approach.

I have though, worked out a solution to put a light and buzzer into the cluster cutout for the tire pressure monitor switch. It's fairly simple: the stock tank level switch, relays, small pilot light, 12V buzzer and a button switch to turn off the buzzer, heaven forbid it would be needed :-) . The concept works but I'm waiting for warmer weather to install. I'm leary of taking apart all the plastic bits needed to run a circuit from the radiator through the firewall up to the cluster in these freezing temperatures. Not to mention frost bitten fingers - unheated garage.

I'd post schematics, but don't see how to insert a file. How does one do that?

I'll do a DIY when I Mother Nature co-operates.

Regards
RDL
***********************
I later figured out how to post images of the wiring diagrams. Here they are.

EDIT: note that the relays showing have snubber diodes indicated. I added those since I found really a great deal on non-protected relays. If you don't have this protections, the relay coils can generate voltage spikes up to 100 V - not good for the electronic modules. BMW uses resistors rather than diodes - a good solution too, except I could find the correct ohms. Nor could I find BMW NC relays that my design needs.
I also have a concern that the buzzer may create interference and interfer with the various control & information busses when it is activated by a low level condition. The electronics supply house assured me not, but I will need to check with an oscilloscope once installed.

Hope this helps

RDL

Some more thoughts.

I've attached a picture of my cluster with the icon/mask I hoped to activate. Yours may have the same mask available.

I based my original plan on the routing and pin-outs in high cluster retrofit instruction, copy attached. Without, the retrofit harness thought, just the connection from level sensor to the LCM.

I couldn't make the low rad icon light up inspite of repeated attempts in INPA and DIS with the "activate" and "cluster test" functions. But, I have a quirk in my LCM. It reports to INPA and NCS Expert as coding index 6. Yet, Revtor (NCS Dummy author) worked out that when reading the LCM it reported parameters for coding index 7 that are not in coding index 6. Revtor couldn't understand why. He'd never run into this condition.

Perhaps this quirk in car explains my lack of success. You might succeed.

Regards
RDL

Forgot to download the attachements in prior post.

Here they are.

RDL

EDIT: don't know what's wrong, I did press the download button this time for sure!

Here they are.

RDL

Thanks RDL,

I will do some research on the Windshield Washer Fluid Level circuit and prefer to tap to that circuit for simplicity reasons.
This way when that dash light is ON, I simply open to hood to check for either coolant and/or windshield fluid levels.
Some warning is better than no warning!

Originally Posted by cn90

Thanks RDL,

I will do some research on the Windshield Washer Fluid Level circuit and prefer to tap to that circuit for simplicity reasons.
This way when that dash light is ON, I simply open to hood to check for either coolant and/or windshield fluid levels.
Some warning is better than no warning!

I couldn't agree more that some warning is better than none. And your idea will certainly give you a warning.

FYI, the sensor, connector & terminal parts for my '03 530i, with the black expansion tank are:
Level sensor 61318360876 qty 1
Universal socket housing 61138365340 qty 1
Bushing contact 61130005199 qty 2

The bushing contacts are the metalic terminals you assemble into the socket housing that plugs into the sensor. They come with leads about 18" long already attached.

Luckily, both switches are closed when level is good, which grounds the circuit from the LCM. It should be relatively easy to wire them in series. My coolant level sensor returns 0.2 ohms when closed. If the washer level sensor is the same there should be no trouble with the LCM seeing a good enough ground to not light the cluster warning when levels are both good.

Regards
RDL

Originally Posted by cn90

Hi guys,

I forgot which year they introduced the Coolant LEVEL sensor (maybe 1999 or so) but my car does not have one. So I want to install it but reading some old posts, it seemed like people have problem installing it for a variety of reasons.

I think it is more a function of high vs low cluster not year.

I've got a 11/97 build date with a coolant sensor on a high cluster.

Originally Posted by dvsgene

I think it is more a function of high vs low cluster not year.

I've got a 11/97 build date with a coolant sensor on a high cluster.

Yes, your correct about high vs low cluster and sensor being installed.

The high cluster retrofit instruction from BMW states:
"The expansion tank must be replaced on cars with M51 engines built before 01/99."

Regards
RDL

Does anyone have the circuit diagram for the Windshield Washer warning light?

check your PM

Originally Posted by cn90

Does anyone have the circuit diagram for the Windshield Washer warning light?

Here you go. Assuming my image upload worked!

Regards
RDL

GSA1, rdl,
Thank you, thank you, thank you!!!
It saved my day!

Now I know exactly what to do. This circuit is complete opposite of the oil pressure sensor:
- Windshield Fluid Level sensor: Full ---> circuit closed ---> continuity of electrical circuit
- Oil Pressure sensor: Good P ---> circuit opened.

Anyway, I will wire the coolant level sensor in series (not parallel) with the Windshield Fluid Level sensor.
It is too cold now, so this project will have to wait a bit!

It'd certainly be nice for this to work...

Hi Cam,

Do you need spare parts?

I can mail you my opened-up expansion tank mechanical level sensor and old coolant electrical level sensor (which was working fine, AFAIK, when I did an entire cooling system overhaul last month).
- BMW E39 failed radiator & failed expansion tank pictorial autopsy

Thanks Bluebee,

I already have the sensor, the problem is time: between work, family, and Christmas coming and few glasses of wine here and there, this project is on hold LOL!

Originally Posted by cn90

I already have the sensor

OK. Luckily, this is something that can wait until you get a round tuit.
If you need a spare when you attack the problem, then let me know.

BTW, it seems the magnetic disk embedded in the float merely wraps around a bulb in the electrical level sensor, somehow causing a circuit to close (or is it open? Probably not.).

Are you mechanically going to try to reproduce that magnetic-switch mechanism?

No, I plan to simply wire the Coolant Sensor in series with the Windshield Fluid Sensor circuit and that is it.

Originally Posted by cn90

No, I plan to simply wire the Coolant Sensor in series with the Windshield Fluid Sensor circuit and that is it.

I approved this method

Originally Posted by cn90

No, I plan to simply wire the Coolant Sensor in series with the Windshield Fluid Sensor circuit and that is it.

Interesting idea but I need you to clarify your method
If you wire in series you need both the coolant and the wash low to trigger the light?
Would you not connect into 'pin' 2 on the output side of switch S136 (wire X10046?)

Could steam from under the hood be enough warning...?

Originally Posted by air_cooled

Interesting idea but I need you to clarify your method
If you wire in series you need both the coolant and the wash low to trigger the light?
Would you not connect into 'pin' 2 on the output side of switch S136 (wire X10046?)

No, any one of the two goes low will open the circuit and the light will show up.

16valex is absolutely correct,

Any of these 2 sensors (windshield fluid or my proposed coolant level sensor mod) is tripped, the dash light is on.

Consider myself lucky, my car has low OBC so no "Low Coolant Warning Light". I was pulling the car out of driveway and saw a small puddle of coolant.
I stopped the engine. Removed Fan Clutch etc.
Initially thought the leak was from Water Pump because I saw coolant under the WP. I was about to remove the WP but then saw coolant dropping from above onto the WP at a rate of 1 drop per 15 seconds!
A quick mirror check revealed that the leak is in fact from the Tstat housing.
Lucky I was patient and looked around first.

Accurate diagnosis = accurate fix.
Wrong diagnosis = wrong fix so to speak.
Went to dealer and got 2 new seals for Tstat (my Tstat housing is only 20K miles old).
Now it is bone-dry but I force myself now to open the hood at every gas fill-up to check all fluids!

This is my proposed plan. I don't have time to do this yet. It is too cold in my garage with Nebraska winter, but will report back in the Spring when I have time to tackle this:




Jason,

By the time one sees steam under the hood, I think it may be too late, we are now talking about $3-4K fix!!!

I just did some more research and this is what I have so far:

- I "borrowed" picture from the internet to show the cluster. So the pic below is not mine but anyway, I have the Coolant Level "Icon" already, but it seems there is no bulb under that Icon.

- In the engine compartment, there is an "Empty" connector near the Coolant Reservoir.

So this whole thing may be much easier than I thought. I am thinking connecting the Coolant Level Sensor into the "Empty" connector and install a bulb into the empty spot in the dash cluster. What do you think?