Low Coolant Level Alarm

Defender200Tdi · 7th October 2004, 09:40 PM

Seems like a good idea, especially for Tdi's.

I read elsewhere that some Rangies had this feature, which is essentially built in to the cap on the plastic expansion tank. I set out on a bit of a search at the wreckers and found this to be the case. The cap is a direct replacement for the standard one on the black plastic expansion tank, but incorporates a small captured, floating magnet and (I presume) some kind of reed switch.

Interestingly, the switch operates on the 'normally closed' basis, and low coolant level will open the contacts. this means that it cannot be simply wired in to a buzzer or light, but will need to incorparate one of the less common 'normally closed' relays.

I haven't actually installed it yet, but confirmed that it works as above with the aid of a multi meter, and that it fits the tank without problem. Once installed I'll do an update, but it seems a reasonably easy way of keeping an eye (or ear) on the coolant level.

Paul [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]

**matbor** · 7th October 2004, 10:48 PM

Sounds interesting, i wanted to do a low level alarm for my disco using the cap, do u know if it will fit a v8 expansion tank ?

Can u post a pic of what it looks like !!!

Thanks.

**incisor** · 8th October 2004, 04:49 AM

excellent little snippet!

a pic or two would be good...

**bigbugga** · 8th October 2004, 05:09 AM

Sometimes the simple answers are over looked.

Nice one, I look forward to the updates and road test report [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]

**one_iota** · 8th October 2004, 05:45 AM

The only problem is that you can loose all the coolant in the system and still have coolant in the expansion tank.

This has happened to me [img]style_emoticons/<#EMO_DIR#>/sad.gif[/img] .

Normally the low level alarm is fitted to the top radiator hose for this reason.

**incisor** · 8th October 2004, 05:54 AM

Originally posted by one_iota
The only problem is that you can loose all the coolant in the system and still have coolant in the expansion tank.

This has happened to me [img]style_emoticons/<#EMO_DIR#>/sad.gif[/img] .

Normally the low level alarm is fitted to the top radiator hose for this reason.

party pooper.......

suppose we could get one of those filter things with the screw lid that was mentioned on the site a few weeks ago and put a sensor in the lid of it?

**matbor** · 8th October 2004, 08:18 AM

Is the coolant system high pressure :?: what with the heat, stream etc.... would there be more chance for coolant leak if you put the sensor at the top of the radiator or in the coolant bottle :!:

**Leo109** · 8th October 2004, 08:25 AM

Matbor,

AFAIK, on all Rangies, Discos and Defenders the coolant reservoir bottle runs at system pressure (15psi?), unlike the atmospheric overflow bottle on most cars. So, from a pressure point of view, there's no advantage one place or the other.

I'm currently working on a coolant loss detector that is fitted to the top of the thermostat housing on my 300Tdi, the highest point of the system. If it works OK, I'll add it to the Thermoguard 'range' of products (then it 'll be 'both of them...')

**matbor** · 8th October 2004, 08:29 AM

Sounds interesting, keep us all up to date.

Matt.

**one_iota** · 8th October 2004, 08:33 AM

There was some discussion about this here earlier on.

http://www.aulro.com/modules.php?name=Foru...ant+alarm#15238

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