A customer who bought two of these alarms for his Landrover Defender TD5's has written fitting instructions for this alarm:-

FITTING A LOW COOLANT LEVEL ALARM TO A DEFENDER TD5

I bought two of these devices and fitted them to my sons and my Landrover Defender TD5s as it is said that the aluminium head on the engine does not stand overheating well even once and repairs are epensive.

The hoses on TD5 defenders are now getting old and they are not fitted with a low coolant level sensor.

I have no affiliation with the seller, he just asked me to give a description of how I fitted them.

Overall, the process was easy and did not require specialist tools. The defender requires the 90mm screw option.

FITTING

1) Remove the radio

I fitted the alarm behind the radio in the centre console, there is plenty of room for the alarm buzzer and circuitry and connection to both intermittent live and negative can be found on the radio wiring harness

2) Routing the sensor wire to the coolant tank

This is the most tricky bit of the entire procedure,

See Image one

On both the vehicle I fitted the device to there was a spare sealed gromet through the bulkhead just to the drivers side of the coolant tank. Snip this off.

I then inserted a piece of cable drawing rod though the cut grommet starting from the engine compartment.

On the TD5 without electric windows it was possible to angle this towards the centre console and push it through and retrieve the end through the radio hole.

On the TD5 with electric windows this approach proved impossible probably to the larger wiring harness behind the instrument cluster. In this vehicle we undid the 4 screws

See Image two

that hold the instrument cluster in front of the steering wheel and lifted it slightly.

See Image three

The top and bottom screws on the left of the picture above

See Image four

The top and bottom screw on the right of the picture above

It was necessary to snip off the red ring connectors on the sensor wires and reattach new ones after threading it through the bulkhead.

On the non electric window td5 the sensor wire was attached to the pull rod through the radio hole and the sensor wire was carefully pulled through the bulkhead.

On the electric window td5 the cable drawing rod was passed from below the instrument cluster into the centre console and the sensor wire pulled to there, the cable drawing rod was then detached , passed through the bulkhead from the engine compartment to emerge under the instrument cluster, the sensor cable was reattached and pulled though into the engine compartment.

3) Completing the sensor fitment

See Image five

New red ring connectors were then attached, and the screws fitted in the positions shown on the coolant tank according to the instructions for doing so supplied with the alarm. It was possible to drill both holes using an electric drill without removing anything but it is easier to if the bonnet is removed as it is such an easy task. Both tanks sealed with no leakage first time and have given no trouble since.

4) Fitting the alarm LED and test switch

Th alarm is loud even when hidden within the centre console and the led flashes a bright alternate blue / red. The position of the led and test switch will be down to personal preference, but I fitted mine on the right side of the centre console as shown below.

See Image si

See Image seven

In order to do this I drill outwards from inside the centre console through the radio aperture making sure to go through the plastic of the side not the metal frame. To do this I used the right angled drill attachment shown below. I had to secure the led in place with a dab of superglue but gaffer tape would probably work too. Perhaps I drilled this hole too big.

See Image eight

If you don’t have one of these just fit it elsewhere.

5) Testing the unit

Switch on the ignition and press the test button , it should alarm .

After this I removed coolant from the coolant tank until the alarm sounded to check the system was functioning correctly.

6) Finishing off

Replace the radio , refi the instrument cluster if loosened.

7) Overall

The coolant alarm has given no trouble since fitment in either vehicle. It is easily tested with the test button. Overall fitment took me about an hour and a half. I think the device gives added piece of mind.


This alarm has been fitted to more than 3000 Mazda Bongo vehicles.

The alarm can be fitted to any vehicle that has a plastic header tank and is 12 Volt negative ground (24 Volt alarm is also available Click Here )

The circuit works by the coolant conducting electricity through it, and holding the alarm off.
The circuit is from one screw through the coolant to the other screw.
No coolant means no flow of electricity and the alarm switches on.

If you have a different vehicle you may need a different length top screw.

You will then need to measure your header tank to get the correct length.

We stock 60, 70, 80, 90, 100 and 110mm long screws.

We have other alarms listed on eBay with these screw lengths included.

If your header tank is metal It can also be used with a float switch (see bottom of tet)

The LED is a flashing type clear transparent when off.

Sensor wires are 2.2 Metres long.

Ring terminals crimped on sensor wires and stainless steel self-tapping screws.

Ring terminal on ground wire.

The new circuit is smaller and is covered with a self-adhesive pad that insulates from being shorted to any metal parts,

and can be used to attach it to any convenient flat clean surface.



General Fitting Instructions.

This alarm has two white sensor wires and it is important
that the plain white wire is fitted on the top of the
header tank and the wire with the black stripe fitted on the side.
The red and black wires are the power wires, the black wire should be
screwed to any nearby grounded metal, and the red wire fitted
to any fused circuit switched on by the ignition key using the lowest
current fuse that is available.
If there is no spare fuse the red wire can be spliced into an
eisting circuit as it uses very little current even when the alarm sounds.

When fitting the long top screw into a Mazda Bongo header tank.
Care should be taken to avoid the vertical baffle plates that crisscross the tank,
they show as squares when viewed from the top.
The long screw is fitted in the top of the tank as close to the tank centre as possible.
If the screw is not started completely vertical it may hit one of the plates
by the time it reaches the full depth.
If the screw tip hit a baffle plate this would stop the alarm from working.
The right side of the tank should also be avoided as it is not deep enough to take the long screw.
The bottom screw should be fitted in any convenient position well below the tip of the top screw.

We have supplied two square plastic spacers that should be fitted as shown in drawing 2.
They need to be drilled in the centre the same size as the header tank holes 2.5mm
Then screwed onto each screw after the ring terminals, because they are forming
threads you will need to hold the spacers with pliers or in a vice, make sure they are
about 20mm along the screw before screwing into the tank, so that they do not
contact the tank until well after the tank thread has been fully formed.
You will probably need to use an electric screw driver on the screws, this should be
done at the lowest speed possible.
If screws are driven quickly it will heat and even melt the plastic of the tank.
The spacers are used because the screw threads do not go completely to the
head of the screw and this would be where they are most needed as the screw is
tightened onto the tank. The spacers make sure that good threads are in the hole as
the screw goes tight. It also means that if you were to over tighten the screw it
would have to strip the spacer thread and the tank thread before failure.
Do not over tighten the screws, only one customer (out of about 3000) has ever reported a leak.
If there was any sign of a leak:-
just loosen the screw about 10mm and put silicone sealant around
threads and between the spacer and the tank then tighten again.
Do not put sealant on the ring terminal or the head of the screw.

I will be happy to answer any questions promptly either via eBay messages


Drill bits needed:-

2.5mm for header tank screws
5mm for LED
7mm for test switch




This alarm will also work with most float switches and without any changes.

Most float switches have the option of N/C or N/O contacts, The sensor wires are connected to the N/C pair.
Some are N/C only and can be used.
Some are N/O only and cannot be used.
N/C means:- Normally closed contacts.
N/O means:- Normally open contacts.