Coolant alarms

[Urban Panzer]

Ok, been looking thru the archives, and read lots of stuff, but would like to see the "general" opinons on whos got what and why...??

Im trying to determine whether or not to do a float switch in the header tank, or just screw in the engine saver and be done with it, but little concerned on which one is best as far as detecting low coolant first ?

over to you guys

[Ean Austral]

Gday Urban Panzer,I have the type that screws into the top radiator hose, beep sounds on start-up to let you know its activated and siren screams when level drops...has saved my bacon a couple times..Best $$$ ever spent on the Disco. Not sure of the brand, but easy when you change hoses just unscrew the fitting and the complete sender comes out and screw into new hose.
Easy, peasy,lemon squeezy
Cheers Ean

[jmkoffice]

U.P, I run the "Engine Saver" low coolant alarm in my D2, my 350SL and daughters Frontera. I am a firm believer in early warning systems.

With regard to the float in the header tank, it should work, the only concern would be, if it were mounted too high, it would be vunerable to the coolant moving around. With the units I use, the sensor is located in a place filled with coolant.

Cheers

[Grumbles]

Mine is mounted vertically in the highest point of the radiator header tank. I believe a sensor in the expansion tank may react too slow and engine damage will occur before it is aware that coolant is dropping out of the engine and radiator.

And it wasn't a shop bought system in a package. Designed and installed by an auto electrician using bought components.

[ozscott]

I have "engine saver" that Dave runs...it is a very slick system. The bleed screw on the top radiator hose junction on the V8 just gets replaced with one (of very very good quality plastic) that has the electrode in. He has a kit for TD5 to suit yours.

Cheers

[Urban Panzer]

Yeah seen that kit and can get it over here to, I like the simplicity of the screw in sensor, its just after reading the detailed post on here ref coolant alarms, it seems the top hose will still be full of coolant even when its loosing it "other" places, so im wondering how much you have to loose before it senses it.

[Ean Austral]

The times mine has gone off the water level was right at the bottom of the header tank, about 1/2 inch in the bottom.The trick is to stop as quick as you can once it goes off. I blew the small hose behind the turbo and it went off I stopped almost straight away and the level was just disappearing out of the tank,finding and replacing that poor excuse for a hose was another story,L/R designers ya gotta love em
Cheers Ean

[ozscott]

UP - mine started to go off once when I had a leak in a heater line to the LPG converter and and it was about a litre and a half down at that stage and the temp had not got above 100 on the Scangauge.

Cheers

[feral]

Yeah seen that kit and can get it over here to, I like the simplicity of the screw in sensor, its just after reading the detailed post on here ref coolant alarms, it seems the top hose will still be full of coolant even when its loosing it "other" places, so I'm wondering how much you have to loose before it senses it.

My thoughts exactly.

My take on the coolant level is that the system will drain/vacuumed the header tank dry first as the water pump will try and keep circulating the remaining water. This certainly happened when I had my pressurized head gasket failure.

I think the confusion is created by the fact that the hose sensor is higher than the tank, particularly on the Td5.

I have the Madman with the sensor in the tank and it worked a treat for about 1300 k's to get the car home.

What would drain first? The tank that has to have the coolant drained/vacuumed out or the higher hose?

Interesting question.

[Redback]

I have the Madmans EMS1, it does low coolent with the small probes in the header tank and coolent temp with the sensor located next to the factory sensor at the end of the top radiator hose at the head.

Battery voltage with high and low alarm
Engine running hours with service timer
Inclinometer and artificial horizon
Pitch and roll
Oil pressure loss warning (from OEM oil pressure switch)
Transfer case temp

So far i'm impressed with it, it's already warned me of excessive EGTs and low coolent, so it works.

Baz.

[jmkoffice]

Yeah seen that kit and can get it over here to, I like the simplicity of the screw in sensor, its just after reading the detailed post on here ref coolant alarms, it seems the top hose will still be full of coolant even when its loosing it "other" places, so im wondering how much you have to loose before it senses it.


U.P, interesting question.

As we know, the screw-in hose sensor, is fitted to hose (5). This is the top hose where coolant flows from the engine to the top of the radiator. There are two smaller hoses which flow coolant out of the top hose to the heater inlet pipe (4) and thermostat housing (13) respectively. The expansion tank (17) has coolant flowing from it through the heater/expansion tank return hose (16) to the coolant pump feed pipe (9). Coolant from the fuel cooler (22) also flows through the heater/expansion tank return hose (16) to the coolant pump feed pipe (9).

Ignoring the other smaller pipes, would I be correct in saying, the expansion tank and top hose would both be ideal locations for a sensor detecting a drop in water level?

If you think about it, the top hose may be a more suitable location as there is less water stored in the pipe itself and it has two pipes which can drain coolant out, thus creating an air lock around the sensor, which is fitted at the highest point of the top hose. Whereas the expansion tank may in fact drain slower as there is more stored coolant.

Any other interpretations or tests people have done?

[Ean Austral]

I have been told by 2 independant L/R mechanics that the correct way to fill and bleed the cooling system is to loosen/remove the bleed screw in the top hose, then lift the header tank up from its cradle and fill until there is no bubbles coming out the bleed screw.
If the senser is located where the bleed screw is then it would have to be very close to level with the header tank, hence the reason for raising the tank when filling/bleeding.
If this is correct then the level in the top hose is same as the tank so the senser should be able to be used safely in either.
Cheers Ean

[ozscott]

I thought my post above turned the question of putting the sensor in the top hose from academic to anecdotal....ie in real life, irrespective of the theory it works and saved my engine whilst there was plenty of coolant left in her and the temp on the scanguage didnt rise...

[adonuff]

Hi all have been considering one for my discovery, Gave some thought to using a Toyota fuel filter alarm, the one that tells you when there is water in the spin on filter, Think with a few mods it could work??

But will watch this forum and see whats reccommended

Andrew

[Slunnie]

Ok, been looking thru the archives, and read lots of stuff, but would like to see the "general" opinons on whos got what and why...??

Im trying to determine whether or not to do a float switch in the header tank, or just screw in the engine saver and be done with it, but little concerned on which one is best as far as detecting low coolant first ?

over to you guys
I have a unit which was made by Redarc. Seems to be good so far although gives the occasional wake up beep. It senses from the resorvour, apparently this is the first place for the coolant to drop if there is a leak.

[Traco]

A TM2 is a good option and comparatively cheap. It attaches to the dash with a digital display showing your engine temp, with data coming from a sensor on mounted the block or heads (I put it under one of the thermostat bolts). You can set the temp at which it sounds an alarm, usually just above the max your engine runs at when hot.

The problem with float types is that they don't let you know if say the fan fails, or a head gasket lets go.

[ozscott]

Engine saver is not a float type but rather an electrode through which a very small current passes.

Cheers

[Grumbles]

The sensor probe continually reads the electrical conductivity [EC] of what surrounds it and sends this info back to its ECU. If the probe sends a different EC reading to coolant then the ECU upon reading this instantly activates the warning alarm. Foolproof system.

[jmkoffice]

A TM2 is a good option and comparatively cheap. It attaches to the dash with a digital display showing your engine temp, with data coming from a sensor on mounted the block or heads (I put it under one of the thermostat bolts). You can set the temp at which it sounds an alarm, usually just above the max your engine runs at when hot.

The problem with float types is that they don't let you know if say the fan fails, or a head gasket lets go.
This heat sensor still relies on conductivity. The coolant level sensor (which is not a float) detects the drop in water level. This will detect a problem far earlier than the external temp sensor. Lack of adequate coolant in the system is the primary reason for the manufacturers temp sensor not working correctly - as there is no coolant surrounding the temperature sensor itself.

[Davy]

Hi All

Just a bit of perspective from a manufacturers viewpoint.

The land Rover header tanks (expansion) have a horrible reputation for
cracking so it never made sense to me to start drilling holes in them for
low coolant sensors.

That leaves the thermostat housing, the top hose and the radiator top tank.

The early V8, and 200/300 tdi have an existing bleed plug in the top of
the radiator tanks which is an ideal position for a sensor.
So I manufactured sensors for them.
We ran a laser level through the engine bay of a 300tdi Defender and established that the sensor is at the same height as the recommended coolant level in the header tank.

The 200/300 td1 also have the same plug in the thermostat housing
but there is always an air pocket underneath it which takes a while to fill on start up and needs an unacceptably long alarm delay or a very long sensor to reach the coolant, so the radiator makes more sense.

The later V8 & Td5 have no bleed plugs in the radiators, which have
plastic tanks which would require drilling and the self expanding type of sensor fitting.
These type of rubber bung sensors are unreliable and the size of hole
needed to be drilled in the tank could compromise its integrity.
In fact many radiator repairers are now refusing to drill holes or fit sensors through plastic radiator tanks.

So.. I manufactured sensors to simply replace the bleed screws in the top
radiator hoses.
These screws are effectivley at the highest point in the system so air can be bled out and are a good place to position sensors.

Just one point someone else made regarding the TM-2 ( Which I am an agent for & also convert to dual sensor low coolant / high temp units)

Never fit the sensor to the thermostat housing, as if coolant is suddenly lost, the alluminium will rapidly cool and not heat up again untill after heat soaks into it from the already overheated cylinder head.
This information came from a man who cooked his Land Rover engine with the heat sensor fitted in that position.
It gives a really close to coolant reading but is not reliable as far as engine protection is concerned.


Davy

[nice1guv]

Just one point someone else made regarding the TM-2 ( Which I am an agent for & also convert to dual sensor low coolant / high temp units)

Never fit the sensor to the thermostat housing, as if coolant is suddenly lost, the alluminium will rapidly cool and not heat up again untill after heat soaks into it from the already overheated cylinder head.
This information came from a man who cooked his Land Rover engine with the heat sensor fitted in that position.
It gives a really close to coolant reading but is not reliable as far as engine protection is concerned.


Davy

That's a take home message! :p Cheers Davy. :D

[disco_thrasher]

The times mine has gone off the water level was right at the bottom of the header tank, about 1/2 inch in the bottom.The trick is to stop as quick as you can once it goes off. I blew the small hose behind the turbo and it went off I stopped almost straight away and the level was just disappearing out of the tank,finding and replacing that poor excuse for a hose was another story,L/R designers ya gotta love em
Cheers Ean

yeah been there :mad:

[wilber]

In my experience..float sensors can be unreliable the older they get...A pressurized header tank is a difficult enviroment for them to operate in and if it's not a pressurized tank then coolant can be lost from the system and still leave the tank full.
My vote is with the "no moving parts" EngineSaver system which has proved it's worth so many times in all situations.

[adonuff]

Hi fitted the engine saver about a week ago, easy to fit got a discount for mentioning where I heard about it and it works really well.

Set it up so the alarm was off at normal operating temp around the suburbs, had it set fairly fine it is sensitive enough to go off when I start to drive in steep hilly areas, had to move the dial a mm to the right and that is where I will leave it.

The only thing I was dissapointed in was the adhesive that holds the crontrol onto your steering column or where ever was not all that sticky.??

Then again it might be due to not cleaning the area? Might have been armour all or simular from the previous owner?? Might be my fault?

I feel a lot happier knowing I do not have to trust the computer to tell me if things get too hot or the coolant leaks.

Think the reason that other Land Rover drivers never wave is possibly due to the fact their spare time is taken up looking to see if any warning lights have come on. Maybe this will help to overcome this ??

Andrew:D

[land864]

So with the TM2 type attached to the block etc what is a safe temperature to set it at.

I had mine done by a LR repair place.

The display is mounted inside the dash under the main cover!

Not sure why they put it there?

The passenger can see it :eek:

I would probaly only be distracted if it were out.

The audible alarm is set on 100 C.

On a recent trip in a 36 degree day towing 1.5 T of camper trailer up a long hill , it got to 98 !!

Pete