Low coolant alarm. Which one?

So I had the rear gasket on the lower part of the thermostat housing go on me last week. Coolant was absolutely gushing out. Lucky for me, I have a nose that requires me to use a yard glass to drink from, so I smelt it pretty quick. So thats all fixed, surprisingly easy job to do, and its got me a little concerned now. If I were to ever lose water again, and I have a cold and my schnozz is blocked, I may be up one of those creeks in a barbed wire canoe with no paddle. I really don't want to be cooking my engine....

I have looked at a few different alarm setups.

Redarc https://www.redarc.com.au/low-coolant-alarm
Davies Craig http://daviescraig.com.au/product/lo...it-12-24v-1035
Engine saver http://www.enginesaver.com.au/Toyota_Nissan.htm
Engine Guard http://www.ebay.com.au/itm/ENGINE-GUARD-EG01-1-New-Model-Temperature-Sensor-Gauge-low-coolant-alarm-/152447318916?hash=item237e917b84:g:PggAAOxyuR5TbBq Q
EG2 http://www.ebay.com.au/itm/SIMPLE-WIRING-TEMPERATURE-GAUGE-ALARM-Detects-Low-Water-Coolant-EG2-/111976228387?hash=item1a124da623:g:H1YAAOSwstxVQgF K
Engine Watch Dog http://www.ebay.com.au/itm/ENGINE-WATCHDOG-TM1-NEW-MODEL-TEMPERATURE-SENSOR-GAUGE-LOW-COOLANT-ALARM-/142263205052?hash=item211f8c3cbc:g:BrQAAOSwECZUrEF k
eBay cheapie http://www.ebay.com.au/itm/Low-Coolant-Level-Alarm-12V-Buzzer-LED-/121532123147?hash=item1c4be1080b:g:89IAAOxyGxxSLdw A

What I don't really want is another display unit on the dash. Just a hidden unit that will scream its titties off when low coolant is detected.
So this knocks out Engine Guard, EG2 and Watchdog. Maybe the Davies Craig one too. Also with the Engine Guard, EG2 and Watchdog, I am not sure how the low coolant part of these kits work, I see no sensor in their kits.

This leaves the Redarc, Engine Saver and the Ebay Cheapie. One on my concerns is will the eBay cheapie and the Engine Saver produce any current through the coolant? Stray currents I really don't want. Then I look at the Redarc unit, Nice and compact, I can hide it away, I can put the sensor in at the bleed hole on top of the thermostat housing, which I don't use anyway, but. The unit self tests every time you turn on the car. I already have two Redarc gauges that do this and to have a third device do it, I reckon will do my head in.

So. Who's running what? What are your thoughts? Are there any other units I have missed?

Thanks in advance...

What about a Murphy low coolant siren
you could hook up a sender to a reverse style horn
they are small and would tuck under the dash easily

Random thought..... what about a flow switch/meter in upper radiator hose?

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I fitted a datatron, made by "flexible drive agencies". Sensor in top of radiator, module under dash, screams with anguish when activated. www.flexibledrive.com.au.

I have the Davies Craig one on my Pajero. I won't be using the same one on the Patrol. It has no self test mode so you never know if its working or not, and if I wash down the engine bay it seems to trigger the sensor, so I am guessing the connection isn't waterproof.

Quote:

Originally Posted by threedogs

What about a Murphy low coolant siren
you could hook up a sender to a reverse style horn
they are small and would tuck under the dash easily

This also uses a gauge, something I dont want.

Quote:

Originally Posted by Turtle_au

Random thought..... what about a flow switch/meter in upper radiator hose?

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Yeah I dont want to be adding adaptors into the hoses. Just means another place for a leak to happen.
I have a spot either in the top of the radiator and also in the top of the thermostat housing, both are there and ready for the job.

I'm leaning toward the engine Saver unit at this stage. I have emailed them and asked about current flow issues causing electolysis, if there is any, with there unit....

Watchful eye on this.

Random thought mk2....
Trying to remember correct terms, I think it is a voltage divider to drive a LED from 12volts. Basically a resistor one end connected to ignition circuit other to one side of LED. Other leg of LED to earth. Correct polarity of LED and correct resistor size and it will light up.
Now put an insulated probe into radiator and connect to middle of resistor/ LED circuit. When probe in contact with coolant it should hold middle of divider to earth, when coolant drops below probe no earth point and LED will light.

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1 Attachment(s)

Got the brain lubed up and decided to draw the circuit up complete with sizing and Jaycar part numbers. LED should be bright enough
Attachment 71099

Quote:

Originally Posted by Turtle_au

Got the brain lubed up and decided to draw the circuit up complete with sizing and Jaycar part numbers. LED should be bright enough
Attachment 71099

Yeah wow. Is there any current flow issues causing electrolysis with this setup?

I've had the Engine Saver in mine for several years. Nice & simple & self tests each time ignition is turned on. Easy to fit to the TD42, just screws into the thermostat housing. Probably much as Turtle's diagram, but with a self test function & a buzzer (loud) as well as the LED. Expensive for what it is, but cheap for what it does.

Mine came on for the first time not long back, just after I changed coolant which needed topping up.

Harder to miss an audible alarm than just a light. The self test is essential imho, otherwise you have no idea if it is working.

Quote:

Originally Posted by mudski

Yeah wow. Is there any current flow issues causing electrolysis with this setup?

Wow, now I have to drag out my metalurgy books. Maybe by choosing the right probe material could make it actually reduce corrosion.

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On electrolysis & low coolant alarm http://www.enginesaver.com.au/Engine...C_DC_Page.html

Quote:

Originally Posted by mudski

Yeah wow. Is there any current flow issues causing electrolysis with this setup?

I wondered the same thing. Pretty sure the commercial units with a probe use an AC current on the sensor to get around the corrosion issues.

https://www.redarc.com.au/low-coolant-alarm

Quote:

Features

AC sensing to avoid corrosion
Suitable for 12 volt and 24 volt systems
The buzzer operates if the sense wire in the system is broken
Built-in anti-slosh delay
Output for external alarm and/or indicator

At 14 volts with a 560 ohm resistor the max current would be 25 mA and only whilst the ignition is on. With positive voltage on the probe any electrolytic action would mean any corrosion would be on the probe.
The bigger problem in vehicles is the galvanic action between dissimilar metals. A mixture of aluminium and iron causes the aluminium to corrode, and this occurs 24/7. That is why coolants need to have corrosion inhabitants. If you used a zinc or zinc plated probe then it would act as a sacrificial anode to both iron and aluminium.

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We were talking about this yesterday, a workmate has the Redarc & has fitted the probe in the top hose using a Davis Craig adapter.
As I see it the top hose and the thermostat housing will have coolant in them right up to when the radiator is empty as the water pump will pick up coolant from the bottom of a half full radiator & pump it through the engine, thermostat & top hose.
My suggestion was to instal a probe in the ZD30's radiator cap which is just a blanking cap & has no pressure relief. It is at the very top of the radiator and would give earliest warning.
Graham

Quote:

Originally Posted by GeeYou8

We were talking about this yesterday, a workmate has the Redarc & has fitted the probe in the top hose using a Davis Craig adapter.
As I see it the top hose and the thermostat housing will have coolant in them right up to when the radiator is empty as the water pump will pick up coolant from the bottom of a half full radiator & pump it through the engine, thermostat & top hose.
My suggestion was to instal a probe in the ZD30's radiator cap which is just a blanking cap & has no pressure relief. It is at the very top of the radiator and would give earliest warning.
Graham

I know with my Davies Craig one in the top hose of the Pajero, that it will set the alarm off with about 1/2 a litre missing. They are pretty sensitive to dropping levels.

I have 2 of the eg-01/02 with 2 sensors, so 4 total. 1 sensor hooked up to monitor water temps in and out of radiator, second monitor is being used on oil, working on hooking this up tomorrow on oil filter and oil cooler. They are simple, robust and aussie made in cairns QLD. The designer is readily avail and spare parts easy to get - have pinched a sensor wire twice - but my error in installation caused that. Happy with the gear and small to mount in the car.

I just spoke to a bloke who has the redarc unit. I asked him about it, since I remembered your thread.
He said the unit takes DC volts, from the car so 12VDC. But the sensor is fed AC volts from the unit..... Hope it helps .

So I looked up the PDF file for it.

http://www.nissanpatrol.com.au/forum...id=71223&stc=1

I ordered the Redarc low coolant unit today. I bought a Redarc brake controller last week and was impressed with the quality of the construction.

Quote:

Originally Posted by jff45

I ordered the Redarc low coolant unit today. I bought a Redarc brake controller last week and was impressed with the quality of the construction.

All my redarc gauges and probes are really good bit of kit. So I will be going with their low coolant alarm.

Sent from Note 4

Getting back to this as I totally forgot about it and now I have a coolant leak. :( So I will be buying the Redarc unit. I knew I had a coolant leak somewhere on the motor when we were coming home from our long weekend trip when we wern't far from home and the Redarc coolant temp gauge was fluctuating a lot at about 5 degrees, and at maybe every one second intervals. Even we rolling down a hill. I thought to myself that the coolant is probably a little low and theres an air pocket in where the sensor is and the splashing coolant on the sensor would make the gauge go nuts.
So the Redarc unit is what I'll get, theres a mob not far form here who have them at a good price, so while my car is off the road for other issues, I'll do this too.

1 Attachment(s)

To fit my Redarc sensor for the coolant I cut off the bleed outlet from my alu rad and tigged a 1/8 npt bung in its place. The outlet had just been blocked off with a rubber cap.
This gives me the sensor as high up in the system as possible.
...
Attachment 72214

Quote:

Originally Posted by jff45

To fit my Redarc sensor for the coolant I cut off the bleed outlet from my alu rad and tigged a 1/8 npt bung in its place. The outlet had just been blocked off with a rubber cap.
This gives me the sensor as high up in the system as possible.
...
Attachment 72214

Where have you put the unit itself John? I'm just about to embark on wiring this in.

Quote:

Originally Posted by mudski

Where have you put the unit itself John? I'm just about to embark on wiring this in.

Just behind the driver's side kick panel. It just fits snugly above my cruise control module.
I drilled a couple of 10mm holes in the plastic so the audible alarm can be well heard.
I used the LED earthing wire for a bright red LED in my centre console just to the left of the rear demister button.
Both work well, they sound and blink each time you start as a self test.

Quote:

Originally Posted by jff45

Just behind the driver's side kick panel. It just fits snugly above my cruise control module.
I drilled a couple of 10mm holes in the plastic so the audible alarm can be well heard.
I used the LED earthing wire for a bright red LED in my centre console just to the left of the rear demister button.
Both work well, they sound and blink each time you start as a self test.

Thanks John. The extra led. Do you think its necessary? Or is it just any old led you used?

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Quote:

Originally Posted by mudski

Thanks John. The extra led. Do you think its necessary? Or is it just any old led you used?

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Mark, the extra LED (small red 12v from Jaycar) is required if you want a good visual indication in addition to the buzzer. The only other way to have a visual is to mount the Redarc box on the dash in front of you.
IMO, the LED is discreet and really catches your eye in case you play loud music, for example. I just prefer the belt & braces approach with something that important.
Of course, it's more work.. :)

Engine Saver is still offered with a discount for forum members. I got mine for $165 ($40 discount) just by asking David:

David Jones.
Enginesaver Low Water Alarms
07 47766334

I saw this thread it has reminded me that my Redarc unit has died. It keeps going off by itself so now its unplugged. Issue now is I cannot find the receipt to claim it under warranty. :(

Quote:

Originally Posted by mudski

I saw this thread it has reminded me that my Redarc unit has died. It keeps going off by itself so now its unplugged. Issue now is I cannot find the receipt to claim it under warranty. :(

Mark, check the spade connector on the sensor to make sure it has good clean contact.

I have added the Redarc to my monitoring instruments as well. I also monitor temps on and off the radiator, plus on and off the oil cooler.

Quote:

Originally Posted by jff45

Mark, check the spade connector on the sensor to make sure it has good clean contact.

Yeah checked all that John. When the sensor is going off I earthed it direct to the -ive on the batt with no joy. The only thing I haven't done it remove the entire sensor wire down to the unit itself to inspect it for any damage.

Quote:

Originally Posted by mudski

I saw this thread it has reminded me that my Redarc unit has died. It keeps going off by itself so now its unplugged. Issue now is I cannot find the receipt to claim it under warranty. :(

Serial number Marko?? I've found redarc to be very flexi and honorable with their warranty etc... Ring em up have a chat, you may be surprised.

Quote:

Originally Posted by Hodge

Serial number Marko?? I've found redarc to be very flexi and honorable with their warranty etc... Ring em up have a chat, you may be surprised.

Yeah I will do. Just copped the daughters flu she had for two weeks. So this weekend is written off to do anything.

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Quote:

Originally Posted by mudski

Yeah I will do. Just copped the daughters flu she had for two weeks. So this weekend is written off to do anything.

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Wouldn't have happened if ya didn't bail Saturday mate! I was in Thomastown at 830 the following morning too!

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Quote:

Originally Posted by rusty_nail

Wouldn't have happened if ya didn't bail Saturday mate! I was in Thomastown at 830 the following morning too!

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But my own bed sooo cozy! And I had something nice to snuggle up too.

Just returned this thread as I want an alarm to fit to the OKA.

I was happy with the 'Engine Saver' in the Patrol, mostly because I could just screw the sensor into the TD42i's bleed hole, so no drilling or hose cutting required.

Of course the Cummins motor in the OKA doesn't have a nice convenient air bleed hole I can utilise.

Soooo.... in the interests of avoiding cutting & drilling, potentially creating leak points, I'm looking at the 'Engine Guard' which is an Overheating alarm, not a low coolant alarm. (It does have a coolant temp sensor which requires cutting or drilling, but I see no point in having this in addition to their cylinder head mounted temp sensor, at least not for detecting 'catastrophic' engine wrecking overheating as a result of a burst hose whether that be coolant or oil.

I already have a low coolant sensor in the coolant expansion tank, but this is more a reminder sensor than an alarm sensor, mounted low in the tank & pumped in from the top of the motor. When it activates it lights up the 'check engine light on the dash.... a light which can be triggered by any number of issues. Determining the cause requires button pushing on the speedo to navigate to 'Faults' where an error code can be read, & then checked against a list of error codes in a manual. By which time if it's telling me the coolant is low there' a good chance the motor will be cooked if I haven't stopped.

An alarm with an audible as well as a visual function is needed. The 'Engine Guard' has both, AND importantly gives a constant readout of the temperature so you always know that it is working.

In addition the Engine Guard can have two temp inputs, so it will allow me to also monitor the temp of the Allison auto transmission- a bonus.

The only possible downside of the Engine Guard is the potential for up to a 20 second delay to the alarm going off if a coolant hose bursts, but I am assured that a motor wouldn't 'cook' in that time. A low coolant alarm might be triggered slightly quicker depending upon where in the system it were mounted.

Cuppa I have used a number of the engine guard devices for water, oil, gearbox, diff, transfer case and even air with the right sensor. I like them, locally made in Cairns, the owner is receptive and happy to discuss and even walk away from an applicationif it wont deliver.

i am using the redarc radiator level alarm and its very sensitive. On corrugations it can fire off though, especially with the cross flow tanks instead of top and bottom tanks. Right now I am using the engine guard to monitor fuel temp on the tank retrun circuit. Once I get the latest cooling mods resolved I intend plumbing the interchiller circuit into the fuel return line - have the heat exchanger ready to go, to ensure the fuel temp remains less than 25 deg C. the recent NT trip had fuel temps at 48-50 on return and this is wasted power - 45DegC is the limit according to all the literature.

Two different technologies , each with their advantages, but dont think you can go wrong with the engine guard product.

I have the Engine Guard 2 probe version. One probe on the front of the motor where coolant exits (next to factory temp sender) and another on cold side of radiator near thermostat housing.

I note there is a 10c difference between temp reported on the front of the motor and that reported by the ECU via my OBD2 scanner thingo. I set the alarms for 100c ... which would mean actual coolant temp would be 110c