Disco 2 Losing Water. Has anyone fitted BMW expansion tank.

Richeee · Mar 19, 2021

Hi.
My Disco 2 is losing a bit of coolant. Not too much and realise that in future some in depth work could be needed as its now done 160,000 miles. Cant obviously see where from at this stage. Not desperate but dont want to get caught out.
In the mean time am fitting a temp gauge with an alarm. Like several others have done.

But also looking at coolant level alarm. Seen that you can get float switches that can be drilled in. Also sensors that can go up to the side of the tank. ( If any body has a current link to where i could get one of these it would be useful as a link i followed is not valid).

But main question is has anybody used BMW tank 17111712641. I was reading about these whilst having a google and just wondered if any body had any experience of fitting these to a td5 as it appears to have a built in level sensor. ?
Or maybe its a non goer and i have my wires crossed as normal.
Thanks guys and gals.

Pawl · Mar 19, 2021

There's lots been fitted on the D2boysclub forum.

swatts70 · Mar 19, 2021

My disco td5 was losing a small amount of water for ages but couldn't see any obvious leaks. My thoughts were expansion tank cap so taped the finger of a rubber glove over the end of the overflow tube to see if it would catch any any escaped coolant. Not a thing.!
Eventually found out it was a pin hole in the lower coolant rail pipes at the bottom of the engine, hidden away behind the plastic cover. Its lined with foam so was absorbing any fluid and stopping it dripping on the floor. The pipes are metal and apparently a common failure as they eventually rust through like mine did.
My pin holed pipe just blew one day and dumped the engine coolant on the drive after being driven one day.
Bit of a pain to replace as need to remove plastic sheild and undo 5 or 6 pipe hose clamps.
And expensive, £200 for a ****part replacement.
You could alway try some UV dye in the coolant first and a UV torch to highlight where your leak is.
If you need to replace lower coolant rail then get some pliers like shown, makes life much easier.

Screenshot_20210319_092852_com.amazon.mShop.android.shopping.jpg

Screenshot_20210319_092810_com.amazon.mShop.android.shopping.jpg

Richeee · Mar 19, 2021

Thanks guys.
Will look on d2boys club forum to find out more.
All these years and did not know about uv coolant dye. Old dogs new tricks. As for the hose clips have a similar tool for those. Mines a bit like pliars with special ends that lock on. Will need to find leak.

Was thinking longer term of permenant level indicator and if anybody has more info on the bmw tank or the external sensor. ?

Hellastony · Mar 19, 2021

I and many others on D2BC have done this, easy (reasonably) straight replacement. Got my BMW tank off the bay, came with the actual level sensor, some don't and they are expensive to buy separately, and recommended to buy genuine BMW only, and fitted in about 1 hour. The only difference is that the bottom outlet pipe on the D2 is kinked, abut it is not on the BMW version, but with careful manoeuvring and adjustment of the loom that is underneath the tank, it will fit ok.

All the information you need here:
http://www.thed2boysclub.co.uk/viewtopic.php?f=15&t=62045&hilit=coolant+level+sensor

Richeee · Mar 19, 2021

Thanks. Just been looking at my tank and taking photos and measurements.
Came to same sort of conclusion and glad to hear that it can be done.
Main problem is slow loss of coolant that i need to address, but trying to find it is proving difficult. Recently replaced thermostat as that was weeping from one of the old joints. Then had air lock in heater. Thought water loss might just be air lock clearing but now convinced that its still losing some where.
But have realised that lack of accurate temp gague and coolant level indicators dont leave much room for error.
Bits for temp gauge are arriving and will now look for expansion tank with level sensor complete.
Thanks for replying. Good to know it can be done.

JUKE179r · Mar 19, 2021

This BMW expansion tank info is on my Disco 2 cheat sheet:

- V8 coolant expansion tank #17111712641; BMW E30 (late '80's / early '90's 3 series / '88-'93 some 5's and M cars specifically *1990 BMW 325i) is identical to the D2 TD5 coolant expansion tank and it is a direct swap which clips straight in.
- ***Thor V8 owners cannot use this model of tank as a direct replacement.*** The BMW tank doesn't have an extra coolant line/port for the V8's Throttle Body Heater (TBH) return hose unless you entirely cap off the TBH's inlet coolant hose from the engine.
- The BMW tank has a low coolant sensor #61311378320 built into it. The BMW tank is thicker in construction. The max coolant level mark is on the front rather than at the side. Bottom coolant pipe is a little bigger diameter and sticks outward, but not so much a problem.

neilly · Mar 19, 2021

I have one, but never fitted it.

One day.

Cheers

DaveM-sport · Mar 19, 2021

I fitted a couple to our D2s just as had a few old spare E36 M3 tanks lying around and thought might as well make use of them

Richeee · Mar 22, 2021

Right. A bmw expansion tank today arrived today. Looks like it will do the job splendidly.
Came complete with a level sensor. But as i was testing the logic it fell apart in my hands. New one ordered. Looks like the reed switch inside was all manky any way.

Quick question. Is the circuit open or closed with the little float containing the magnet. If the float is up i presume the circuit is closed but then opens when it drops cutting off the circuit.
Thinking which relay i need to get to get, to power the wsrning light / buzzer.?

I might just have to wait till the new one turns up and not break that one. Then test it.

Andy Warren · Mar 22, 2021

Richeee said:
Right. A bmw expansion tank today arrived today. Looks like it will do the job splendidly.
Came complete with a level sensor. But as i was testing the logic it fell apart in my hands. New one ordered. Looks like the reed switch inside was all manky any way.

Quick question. Is the circuit open or closed with the little float containing the magnet. If the float is up i presume the circuit is closed but then opens when it drops cutting off the circuit.
Thinking which relay i need to get to get, to power the wsrning light / buzzer.?

I might just have to wait till the new one turns up and not break that one. Then test it.

Hi, it should work the other way round, low water level float drops down which closes or completes the circuit & bring warning light/buzzer ON. Water level normal float up opens or breaks the circuit & warning light goes out, just think of your toilet cistern

.

Stanleysteamer · Mar 22, 2021

Andy Warren said:
Hi, it should work the other way round, low water level float drops down which closes or completes the circuit & bring warning light/buzzer ON. Water level normal float up opens or breaks the circuit & warning light goes out, just think of your toilet cistern.

Or a brake fluid warning light, which used to, and may still, be part of the MOT although that seems not to be so obvious nowadays.
But throughout this thread I have been wondering if anyone ever modified a brake fluid reservoir float operated switch to do what you want.
Seems not.

sierrafery · Mar 23, 2021

Richeee said:
Quick question. Is the circuit open or closed with the little float containing the magnet. If the float is up i presume the circuit is closed but then opens when it drops cutting off the circuit.
Thinking which relay i need to get to get, to power the wsrning light / buzzer.?

The BMW tank's sensor is N/C when full and opens when the coolant level drops, you need a relay's N/C contact to trigger the warning as in the attachment. I dont have fuel filter water sensor, i spliced into that warning's circuit so when i see the water in filter warning i know the level is low in the tank, on manuals the transmission oil temp warning can be used too(in this case earth is needed to terminal 30)

Richeee · Mar 23, 2021

Thank you.

Will update as i install.

Richeee · Mar 23, 2021

Found the leak.

Its dripping onto the engine mount from the fuel cooler. Just see it in the photo.
Another job to do.

Richeee · Mar 24, 2021

Took the cooler off today. Not too difficult but the amount of sludge was depressing.
In one end appears to be a thermostat spring or pressure spring. This was completely bunged up. Looking better now after a soaking in diesel and a blow out with air. Waiting for seals and clips to arrive.
Also waiting for other bits to install temp sender on top hose and coolant level alarm.

Richeee · Mar 27, 2021

Seals and clips arrived so cleaned and reassembled the diesel cooler.

Started on fitting the bmw expansion tank.
Knew that the outlet was a different size but managed to fit. Also knew that it exits at 90degress to the tank , but when fitting found that the hose was bent double. There appeared to not be enough room under the fuse box.
Bit of investigation found a bracket located there and supported part of the fuse box and part of the loom.

Decided to temporarily remove fuse box and remove the bracket The fuse box seemed to be adequately supported either end and decided to lift the fuse box 10mm by putting spacers between it and the remaining supports..

Gave me a chance any way to check the old ecu for oil. All clear.

After removing the bracket and raising the the fuse box by 10mm still thought that a bit tight with the hose under the fuse box , decided to notch the locating bracket under the new expansion tank.

This moved the tank away from the fuse box a bit more. Now happy that it all fits nicely. It might just be that my hose and loom / fuse box just had an interference that others did not have. But i was not happy initially but am now.

Now just got to wire up the level sensor which I can confirm that when the float is up, no current flows , but when down it completes the circuit.
Also have to wire in the new temp sender and gauge.

sierrafery · Mar 27, 2021

Richeee said:
Now just got to wire up the level sensor which I can confirm that when the float is up, no current flows , but when down it completes the circuit.

Then that's not a BMW level sensor cos as i said that's certainly closed with full tank and opens when the coolant level in the tank drops, so if your's closes when the level drops you dont need any relay just wire it directly as to switch on the warning

Richeee · Mar 27, 2021

My thoughts were that I concurred with your self. But when it arrived and I tested it it was the opposite and no relay required.

Thanks for all the help.

sierrafery · Mar 27, 2021

Did you check it in water ? If not check again, i fitted two myself and both were closed with full tank

Disco 2 Losing Water. Has anyone fitted BMW expansion tank.

Well-Known Member

Well-Known Member

Active Member

Well-Known Member

Active Member

Well-Known Member

Well-Known Member

Well-Known Member

Active Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Attachments

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Similar threads