Coolant Level Sensor Manufacturer's Instructions

[vindaloo]

I now have permission from the manufacturer of the K Series Coolant Level Sensor kit to publish a slightly cut-down version of the instructions on the forum. This may help people who are a little unsure about the complexity of the installation to make up there mind if they would like to order a kit or not.

Any questions please feel free to ask.
Jim

COOLANT SENSOR KIT INSTRUCTIONS.


Principle of Operation

The sensor monitors the coolant level by sending out an infrared beam. While its tip remains below the coolant surface, the beam simply travels away through the coolant. If the level drops enough to expose the tip, which is positioned at the ‘Min’ mark, the beam is internally reflected and activates the warning. The warning will remain on until topping up the coolant covers the sensor again.

These instructions are based on a RHD vehicle. Fitting the system to a LHD vehicle is basically a ‘mirror image’ of this.

Contents of the Kit

Expansion Tank with pre-fitted Sensor Module
This is a pre-used expansion tank, specially modified to take the sensor. Your original tank will not be needed but the pressure cap may be retained if suitable. More details on the pressure cap are given below. The sensor is correctly lubricated and torqued in the mounting and should not be dismantled. The sensor cable has three spade connectors.

Wiring Harness
This has two main sections, encased in flexible conduit. Both parts are pre-connected to the Electronic Control Unit (ECU). The complete assembly should be installed as one unit. Also included is a 15 Amp fuse with a spur. The spur provides power to the ECU through a 100 milliAmp in-line fuse.

Electronic Control Unit
This custom made unit is encapsulated in resin to make it completely weatherproof. When the ignition is turned on, the ECU provides a system check, indicated by the interior LED flashing green for five seconds. The same LED unit gives a pulsing red warning in the event of low coolant level. This warning will continue while the coolant level is low and the ignition is on. It will continue to flash for five minutes after ignition is turned off. The ECU will be mounted on the outside of the engine fuse box. The same visual signals are emitted by the ECU itself, so that an activated state can be seen when the bonnet is open. Keep the ECU protected in the bubble wrapping while you’re installing the harness.

Driver Warning System
The dual-colour warning light (LED) may be installed almost anywhere on the dash. There are various options you can consider for placing it and there’s a good degree of freedom with the generous cabling. The chrome lamp holder requires an 8mm hole for panel mounting and is provided with a spring washer and locknut. Since there are too many possible locations to describe here, this bit is up to you. The warning lamp has four spade connectors to join it to the main harness.

Miscellaneous Bits
Silicone/Fibreglass heat insulation sleeve
Small, medium and large grommets
Zip ties (10)
Flexible wire probe with pull-through string
A spare 100 milliamp Fuse

Pressure Caps
The tank supplied requires the later ‘140’ rated pressure cap. If your cap is the old ‘100’ type, it should be replaced with the self-venting ‘140’. The number is on the outside (* see photo below) and on the end of the inner valve. The ‘100’ type cap was used with the earlier black expansion tank which has a separate overflow pipe. The ‘100’ cap vents through the filler neck and into this overflow pipe. In the later (yellow) tank, the ‘100’ cap will not vent properly.




The branches and the connections to the ECU are ready made, so you don’t have to do anything. All you have to do is install the harness and make the earth connection. Then you connect up the sensor head and the LED warning light to the harness and connect the harness to the power supply.

Apart from the kit, you'll also need a few tools, screwdrivers, spanners/sockets, etc. An electric screwdriver/drill or a hand drill should be used to cut a 7mm and an 8mm hole through the plastic components. A 3mm pilot bit is recommended for both. A roll of PVC tape will be handy, but not essential, for securing the harness connections. A suitable is needed to raise and remove the left front road wheel to allow access to the wheel arch liner. Use axle stands for safety.

We suggest that a copy of Haynes Manual No4292 is available if you are unfamiliar with certain tasks.

Replace the Expansion Tank
Up to a litre of coolant will be drained off to remove the old tank. A length of plastic tubing can be used to syphon some out via the filler neck, especially if it will be reused. Do not suck coolant up by mouth! There’s no need to drain off all the coolant unless you intend to renew it. Release the hose clip (*) with pliers and pull off the small hose attached near the pressure cap. It’s the hose that goes to the engine. Older (black) tanks have a second overflow pipe, which can be ignored. Note ‘140’ on the cap (*).


Remove the tank securing bolt (8mm) shown above (*). Release the mounting tongue under the bolt and then lift the tank to your left to free the two push-in lugs on the right hand end. Shuffle the tank clockwise and disconnect the bottom hose. Getting at the lower hose clip may require some extra dismantling (refer to Haynes if necessary). This will release more coolant to the level of the connection. It’s easiest to just let it run away. Now remove the tank. Watch the radiator fins aren’t damaged as you do this.

Place the E-Zee kit tank with sensor into position and connect up the bottom hose, taking care not to trap the sensor wiring. Leave the tank loose.

Positioning and Routing the Harness
Power to the ECU is provided by a spurred 15 Amp blade fuse which will replace Fuse 4 in the engine fuse box. The spur is connected a 100 milliAmp in-line fuse, which protects the ECU. The in-line fuse will reside in the fuse box. It has a spade connector to join it to the harness. The harness will enter the side of the fuse box. This provides security for the wiring and gives a nice fitted look.

Disconnect the Battery (Advisory)
To prevent the possibility of causing a short while working on the fuse box, you are advised to disconnect the battery. If you decide to do so, ensure you have any access codes for your radio, etc.

Cut Entry Hole into Fuse Box
On the nearside of the case, there’s an access blanking disc molded into the side (*). This will provide the route for the power supply.


Open the fuse box lid. Release the box from its mounting by removing the two large self-tappers at the rear and the 10mm bolt at the front. This allows the box to be lifted slightly and wedged up so you can drill through the blanking disc. If necessary, mark the centre of the disc (lid closed) and using a 3mm bit, carefully drill a pilot hole through.



Now using a 7mm drill, carefully enlarge the pilot to make a 7mm hole. The plastic is soft, so care is needed if using power tools. You can do it by hand.


Refit the fuse box.

Access to Interior
The wiring harness starts at the fuse box, onto which the ECU will be attached. The front harness to the expansion tank is very simple to fit. The rear harness into the dashboard area is slightly more involved and runs first into the upper plenum. From there, it enters the space above the wheel arch liner. Located high in this space is a grommet in a hole giving access to the inside, just above the glove box fuse board. From there, it’s a simple matter of taking the harness above the passenger foot well, then behind the dash to the warning lamp. The required earth connection will use the standard earth point on the inner wing/suspension strut panel.

Harness Installation
1.Remove the nearside windscreen cowl panel (*) as described in Haynes (Page 11.7). Beneath this is the splash panel, which covers the plenum chamber (this is where the pollen filter is housed).



2. Remove the splash panel.

3. Just below the bonnet stay, you’ll see the top of the rainwater drain tube. Forward of this is a pair of holes in the bodywork. One or both may be taped over. You‘ll go into the wing space through the front one, near the plastic screw that fastens the splash panel. Peel off any sticky tape covering the hole.

4. If you now look at the plenum wall, just forward of the first hole, you’ll see another hole through the wall into the engine section. The harness will pass through these holes and into the inner wing space.

5. Both holes will be fitted with grommets to support the harness. There are three grommets supplied with the kit and it’s pretty obvious which holes they fit. Here are the two plenum holes (small and medium grommets (*)).



These grommets are already fitted on the harness.

6. Remove/partly remove the nearside front wheel arch liner.
Details for doing this are given in the Haynes manual.
Note: We removed the liner completely to enable photos to be taken. It’s possible to route the harness through to the inside by releasing only the rear part of the liner.

You might want to have ready some new plastic screw-rivets or multi-use push rivets, for replacing the liner. Removal of the fasteners often damages them and they may be reluctant to re-tighten. You can get 8mm push rivets from eBay as well as stainless steel self-tapping screws to replace any damaged during removal. The self-tappers are No4 x 1/2” pan head Posidrive type. You may also need M5 x 15mm stainless steel washers to make a tidy job.

7. With a clear view into the wing space, you should easily see the routing for the harness.
At the top you’ll see the end of the rainwater drain tube (*) mentioned earlier. This passes through a large hole in the upper wing. The wiring harness will enter the wing through this hole and exit through the rear hole (seen with a blanking grommet (*)), which leads to the interior.

8. Keep the ECU protected in bubble wrap, unwind the harness and place it on the nearside corner of the slam panel and wing, near the fuse box. The shorter (front) section should be laid towards the expansion tank. Lay the longer (rear) section along the wing area towards the plenum. The next step is to attach the ECU to the side of the fuse box.

9. Close the fuse box lid and engage the latch. Do not proceed to Step 10 without fully closing the lid.
Give the fuse box outer wall (below the lid) a wipe over with a clean rag to ensure it’s free from grease and dust.


10. Unwrap the ECU and peel off the backing from the adhesive foam. Without it touching the box, position it centrally below the lid. Now press the ECU (*) onto the fuse box wall. It will stick instantly, so be sure to position it right before it touches the box.




11. Locate the electrical earth point on the inner wing. It’s on the front face of the suspension strut housing. Using a suitable spanner or socket, remove the bolt (*). The rear harness earth branch has a ring connector which should be fitted on the bolt. Refit and tighten the bolt.




12. Take the longer (rear) section of the harness and note the two grommets retained with a piece of tape. Take the end with four connectors and pass them through the first hole into the upper plenum area. Carefully pull the harness through to take up the slack. Remove the tape so you can slide the small grommet along and push it through the hole. Now move the second, larger grommet to the hole and fit it into position.

13. The harness must now be routed through the smaller hole and into the wing space via the drain tube hole. The only way to do this is to use a wire probe. There’s one in the kit.

14. Tie the string around the harness casing near the end. The connectors must be free and separated from each other.



15. Make the wire slightly curved and then push it into the plenum hole, holding it so it heads towards the rubber drain tube. By looking under the wing, you’ll see the wire when you’ve got it right. Use a small screwdriver or long nosed pliers to pull it through the large hole as shown in the next photo.



16. Pull the wire/string into the wing so the connectors are seen through the large hole. Using some wire or long nosed pliers, maneuver them one at a time through the hole. When all four connectors are through the hole, pull the rest of the harness through.



17. Untie the string. Pull out the blanking grommet from the hole leading inside the car (* above photo). Replace this grommet with the one supplied in the kit or, cut a 7mm hole in the original using a cork borer or maybe a Stanley knife, etc.

18. Go into the passenger foot well and release the glove box fuse panel cover. Refer to Haynes if necessary. It is held in place by two screw fasters at the front and two at the back

19. From under the wing, push the harness through the grommet to the inside. Go inside and pull the harness though.

20. Take up the slack under the wing. Keep a check on the top end so the small grommet isn’t pulled through its hole in the plenum. Now fit that small grommet in place so the plenum link is made tidy. Do the same under the wing, ensuring the harness is well clear of the drain tube.



21. You should decide where to install the warning light. This needs an 8mm hole to mount the bezel using the backing nut and washer. It can be just about anywhere and you should have enough cabling to connect to it. Lay out the harness over the passenger foot well and across to judge the locations. The LEDs have a 20cm lead.

22. Feed the main harness across to the intended location. To mount the light, an 8mm hole is needed. When you’ve decided the position, use a 3mm drill to make a pilot hole. Enlarge this to 8mm. This will allow you to feed the individual connectors, then the conduit through from the front. Before doing so, unscrew the mounting nut and spring washer from the LED holder and retain safely. If necessary, pull the end of each cable from the split conduit so the connectors can be handled individually. When all four are through the hole, push them back into the conduit. Now winkle the spring washer and mounting nut back onto the conduit. Push them to the rear of the mounting panel and tighten the nut to make everything firm.

The four LED connections MUST be colour matched to the main harness or the system will not operate correctly and may burn out the LEDs. Carefully check each wire in the main harness and connect it to the same colour wire from the LED unit:
black to black
white to white
purple to purple
green to green

The connectors are 2.8mm spades and are totally enclosed. Insert them firmly, so the join is completely insulated. As added security, tape up the joins with electrical tape so there is no possibility of being pulled apart. The next photo shows the warning light (*) mounted on the panel near the cigar lighter.



23. Tidy up the new wiring behind the dash, using zip ties if necessary. The harness going over the foot well can also be tied up, but the fuse cover will hold it in place, so refit the cover.

24. Under the bonnet, place the front harness around the fuse box and across the slam panel to the expansion tank and the sensor connectors. Before connecting up, slip the silicone-fibreglass heat insulating sleeve onto the main harness. Connect the three connectors to the sensor as follows:
Red to Red
Blue to Blue
Black to Black



Ensure each connector is pushed home.

25. Now slide/shimmy the insulating sleeve up the harness (keeping this reasonably straight makes it easy), over the connectors so it buts up against the sensor head under the tank. Use a zip tie on the other end to hold it in place on the harness



Now refit the tank, replace the set bolt and attach the upper engine hose. Position the harness under the edge of the slam panel. Zip tie the sensor leads so that the silicone sleeve doesn’t rub the radiator and tie the harness to suitable points under the slam panel to make it tidy.

26. Refill with coolant. We recommend filling to about 5mm above the 'Max' mark. This level may require adjustment later. The sensor tip is on the internal ‘Min’ mark and should be clearly visible through the coolant. Check the hose connections for leaks and fix if necessary. Ensure to bleed any air trapped in the system. Refit the pressure cap.

27. Open the fuse box to prepare the power connection. This involves first feeding the remaining branch on the front harness through the entry hole you drilled in the side. This branch contains a red wire with a spade connector. Push the connector and conduit through the hole until about 25-30mm is inside. The conduit will be a firm fit in the 7mm hole and needs no further attention.

28. Remove Fuse 4 (15 Amp - blue). Refer to the drawing below for identification.



This is replaced with the 15 Amp spur fuse included with the kit. The spur fuse is connected to an in-line fuse holder containing a 100 milliAmp system fuse. Fit the 15 Amp fuse so the right angled spur faces forwards.

29. Join the in-line fuse connector to the harness (red). If desired, add some electrical tape around the connection for extra security.



Before closing the fuse box lid, arrange the wires to make a tidy loop, clear of obstructions. Also ensure nothing will be snagged or trapped by the lid. Close the lid.

30. Refit the plenum panels, wheel arch liner, the road wheel and remove the jack/axle stands.

This completes the installation. The system should now be tested.


Testing and Using the Sensor

The expansion tank must contain coolant at or above ‘Max’ level and the pressure cap must be in place. The sensor receives power at ignition on and while the engine’s running. It remains active for five minutes after ignition off.

When the ignition is turned on, the system self-test should confirm it’s ready by the flashing Green LED in the interior warning light. The ECU will flash a similar signal which can be seen from under the bonnet. The test lasts five seconds. The engine may be started at any time during or after the self-test. If the coolant level is satisfactory, no further signal will be seen until the next engine startup.

If no green LED shows at ignition on, check the 100 milliAmp in-line fuse. Replace if necessary, but try to establish why it blew. If the fuse is OK, check all the connections and ensure all wiring joins are colour-matched. Do not proceed until the self test is correctly activated.

If the coolant level is below the ‘Min’ marker at ignition on, the Green test LED will be accompanied by a flashing Red warning. The ECU will show the same thing. The Red LED will persist after the Green self test period ends and for as long as the ignition is on and then for a further five minutes after ignition off. The only way to stop the Red warning is to top up the coolant and replace the pressure cap.

Under normal conditions, the initial Green test LED is the only signal you will see.

If while driving, a coolant leak causes the level to fall below ‘Min’, the Red LED will begin flashing. This will continue while you drive, so should be attended to as soon as possible. Driving the car with the red warning on could be inviting problems like a blown head gasket. The cause of coolant loss should be rectified. It requires the coolant top up to prevent it flashing at the next start up. Replace the pressure cap after adding coolant.

A more comprehensive testing regime, false positive detection and operating description is provided with the kit.

[Jules]

Thanks for posting that Jim.
I'm sure it will put a lot of 1.8 owner's (or KV6) minds at ease.

However, let it be said it won't prevent the 1.8K series engines suffering head gasket failure, or lower liner leakage, so let's not give owners a false sense of security!
The monitoring system will however give an early warning system to prevent the engine cooking and melting the liners into the soft cylinder head.

It will also let KV6 owners know when their thermostat housings have given way!

That said, EVERY water cooled engine in the world should have a coolant sensor...............it's just as important as the oil pressure switch/lamp.