Ranger Mods

After some consideration on where to install the RedArc sensor I have confirmed with RedArc that their 1/8 NPT sensor that is supplied with their low level coolant alarm kit can be replaced with a Stainless Steel rod. All the sensor does is make an electrical circuit connection through the coolant to earth, if the circuit is broken by the coolant level dropping then the alarm goes off.
My solution was therefore to buy a another coolant header tank cap from the local Ford dealer and drill a 3 mm hole in it in the center. Into this hole I inserted a 3 mm 304 grade S/S rod with an "E" clip retaining an "O" ring pressed tight on either side of the cap top - I cut the length of the rod so that it is 15 mm deeper than the normal coolant level although I suspect it could be cut so its only immersed by about 10 mm.
Once assembled I coated the "E" clips and "O" rings with body sealant urethane to ensure that once it sets I have a water and pressure tight penetration. Remember the Ranger system runs at 22 psi, a fair bit higher than most conventional coolant systems.
On the other (outside) end of the rod I crimped a short 100 mm length cable with a male 1/4" spade connector for connection to the RedArc loom connection to the control box.
I'm at a loss as to why Ford produce an off road vehicle that gives you an alarm for low water level in the windscreen washer tank but not a low level of coolant.
Just on a quick vertical measurement that I have since carried out if my coolant drops 15 mm and the Redarc low coolant alarm goes off the cylinder head, engine block and radiator will still be fully flooded with coolant.

I may have misunderstood your terminology, but did you install the sensor (stainless steel rod) into the top of the radiator or the overflow header tank?.

shallowal wrote: ↑Thu Sep 24, 2020 10:04 am I may have misunderstood your terminology, but did you install the sensor (stainless steel rod) into the top of the radiator or the overflow header tank?.

I installed it in the Header / Overflow Tank pressure relief Cap.

The cost of the cap from my Ford dealership was $12.90 inc. GST, the 304 grade 3 mm diameter stainless steel rod was the princely sum of $5.00 for a 300 mm length which I cut down to the correct length I wanted.

I already had the "E" clips and "O" rings in Aldi kits that I'd bought over the years ( just in case I might need them one day ) and I used some Urethane body sealant out of an existing tube.

I opted for doing the install of the sensor/probe into a second cap in case it didn't work.

I tested it by running the engine and then slowly unscrewed the cap until the probe / sensor was just out of the coolant and sure enough the alarm went off.
The engine and the coolant was obviously not up to temperature and pressure.

I thought it was supposed to be installed as near as possible to the top of the radiator in the main coolant flow. ie either the top of the top hose, or into the actual top of the radiator. If it's installed in the overflow tank then it's only measuring the excess coolant from expansion, not the actual coolant in use. ie if you burst a hose or develop some other leak that depressurises the system, then your sensor wont notice the loss because no coolant is being removed from the overflow tank.

shallowal wrote: ↑Thu Sep 24, 2020 12:50 pm I thought it was supposed to be installed as near as possible to the top of the radiator in the main coolant flow. ie either the top of the top hose, or into the actual top of the radiator. If it's installed in the overflow tank then it's only measuring the excess coolant from expansion, not the actual coolant in use. ie if you burst a hose or develop some other leak that depressurises the system, then your sensor wont notice the loss because no coolant is being removed from the overflow tank.

No, the header tank has three (3) hose connections.
Two are above the coolant level, a 6 mm is connected to the top of the radiator, the second is a 8 mm connected to the thermostat housing / water pump the third , at the bottom of the header tank, a 15 mm is connected to the bottom of the radiator.
Should there be a leak in the coolant system the pressure in the header tank will force/assist coolant from the tank into the bottom of the radiator and into the coolant circulation system.
While you may well be right as to the ideal position for the sensor there are a couple of issues. One the plastic header cover on the standard OE radiator isn't thick enough to be tapped, its at best 2 mm thick, also in drilling it how do you guarantee that none of the drilling swarf wont get into the coolant system ?
Secondly the top hose. Yes I guess you could install a plastic or aluminum spool piece that has a 1/8 NPT taping but to do so would entertain cutting at least 25-30 mm out of the hose immediately after the 90* bend and I was concerned that if I did that it would put a strain on the plastic thermostat / water pump housing due to the lack of flex.
While I don't have a standard radiator - mine is an all aluminium Koyorad, I could have had it removed, drained and a 1/8 NPT socket soldered into the top header tank, the estimated estimated cost of this was $50-80 - or I could have installed an aluminium spool (that I have - with a 1/8 NPT tapping) into the top hose, but for the reason I explained I was hesitant to do this.

The sensor is sensitive to coolant level, the second its exposed and out of the coolant it loses its electrical circuit and it sounds the alarm. I think my solution, which works and has a far lower cost and almost zero risk factor was the right was to go.

If I drilled Hole in the centre of my header tank cap it would go through the valve! So the cap would no longer hold pressure.

Putting a fitting in the straight section of the top radiator hose would be ok as you would still have the bends to flex.

Relying on sealant to hold pressure would not be an option I would consider.

Bala1 wrote: ↑Thu Sep 24, 2020 4:07 pm Relying on sealant to hold pressure would not be an option I would consider.

Neither would i

If my radiator was alloy I know where I would put it, the sensor is a good idea though, thinking it is now on the to do list.

I will take some photos of it later today, it's to one side it the relief valve so it in no way affects the operation of the cap and the sealing is accomplished in the main by the E clips and O rings, the Sikaflex urethane is there mainly to ensure the seal. The reason I used a replacement cap was to ensure it worked and sealed before I trusted it, it's now been on for well over two weeks and not a single drop of coolant has leaked.

As the fitting is in the cap it would not leak coolant, if it did not seal then the system would not hold pressure.

I would have thought that after all you have spent on this car the cost to get a weld job done on the radiator would have been the way you would go?

I have a temp line sika flexed under the radiator hose going into the top tank of my farm backhoe, but if it were a good car with an alloy radiator I would have machined up and welded a fitting into the tank. No thought of it ever failing then.

Ian back in 2018 you posted on the other site that you had fitted a coolant level sensor to this rig of yours, you did not mention the brand and nobody asked but did that unit fail or are you just going with a better mousetrap with the Redarc?

Hilly13 wrote: ↑Fri Sep 25, 2020 3:22 pm Ian back in 2018 you posted on the other site that you had fitted a coolant level sensor to this rig of yours, you did not mention the brand and nobody asked but did that unit fail or are you just going with a better mousetrap with the Redarc?

Yes, I was getting some intermittent false low level alarms and in my opinion by their reputation the Redarc is a better mousetrap. If anyone wants a alloy fitting to go in the top hose, let me know.

As I promised I attach photos of the sensor in the header cap, my apologies for the poor focus, I have only a Olympus Pen camera and the best lens I have for it is a 14-42 mm .
It does NOT leak, I've had it on the system now for well over two weeks but yes, if I can find someone able to weld a 6 mm thick plate onto the top of the Koyorad so that I can drill and tap it 1/8 NPT I'll probably end up going that way but for now this works.
I simply didn't like the reduced movement / flex in the top hose once the top hose fitting was installed and that weak looking plastic thermostat housing, if that were to snap when I was out in the bush it would be a calamity. I always carry a spare header cap so were this to fail I'd simply replace the cap and carry on my way.
The installation of the 3 mm stainless steel rod does NOT affect the operation of the pressure relief valve. Once you strip it down you will see there are two "valves". Pressure in the system lifts the first causing the excess pressure to pass under the second, lifting it allows the pressure to pass through the 8 openings above the first sealing "O" ring into the header tank chamber below the second "O"and then to atmosphere. I would have thought that there would have been some sort of thermostatic control as well, but there isn't.

To do this you need to really have a spare cap. It has to be dissembled - very carefully. and make a note of the direction of the different components.
I drilled the holes on my "toy" bench lathe to ensure that they were central - I guess you could do them by hand but .....!
I flattened the top end of the rod first so that the 1/4" spade connector on the Redarc loom would fit it, the alternative would I guess be soldering a terminal on first, soft solder doesn't always like stainless steel.
Once the holes have been drilled it can be installed and the pressure valve re-assembled. No special tools are required but strong fingers are an advantage, the main spring is a strong one.
The assembled valve then slides over the rod and is pressed back into the cap.
You aren't able to see the method I used to seal the rod where it passed through the cap - I simply couldn't get that close to it with my camera. its achieved by two neoprene "O" rings and two "E" clips one pair either side of the cap, the rod is 3.2 mm the holes drilled are 3.0 mm a tiny dob of Sikaflex was smeared over the inside "O" ring before the valve was pressed back into the cap.

For what it's worth Ian I think the idea in itself is rather ingenuous.

Hilly13 wrote: ↑Sat Sep 26, 2020 7:02 pm For what it's worth Ian I think the idea in itself is rather ingenuous.

It works, it doesn't leak and by carrying a spare header cap (as I always do along with top and bottom hoses, belts etc. ) it's failure presents little risk - as against the plastic connection snapping off the thermostat housing !

I'll keep my eye out for a gun welder who can weld aluminium and who can weld a 6 mm thick plate on top of the Koyorad radiator in situe, so I can tap it 1/8 NPT until then this is a low risk alternative that works -- and it was fun building it, it was something to do in the man shed during Covid-19 "isolation" and far more interesting than cutting lawns and pruning hedges.

Talking of which Julie and I went along to get tested - something we decided we would do on a monthly basis - we got tested with a swab shoved down our throats and up our noses and were then told we had to self isolate and NOT leave our until we received conformation that we were virus free !!

The installation, again sorry about the poor focus, put that down to the camera, the lens and my temporary astigmatism.

If I were doing the weld on fitting to the radiator i have enough gear in my shed to do so.

I would need the coolant drained and the electrics would be in my mind so i would just pull the radiator out. Someone may be able to confirm if a battery disconnect ill make a welding safe for all modules.

I would make the fitting to be welded and tap the thread first, then just drill a clearance hole in the tank, clamp the fitting in place out the back of the tank and weld away.

I don't think that the modules are an issue, when my Wildtrak was being "built" all they did was to disconnect the battery, they then left it for 1/2 an hour - presumably to allow any built in batteries to drain while they removed the tub, and then the welder plated the chassis rails using a MIG welder. They then painted the plates, fitted the Frontier long range fuel tank, the OME BP-51 suspension to the rear axle extended the rear axle breather to the engine bay ( while it was all easier access ) and then they re-fitted the tub which by then I believe had the Ascent canopy fitted to it. The following day they poured some diesel into the tank to prime up the pumps and filters and the engine started first turn. So, that being the case I think the the radiator could simply be partially drained and left in place but I'll get a few "second" opinions
I did a TAFE course some years ago on emergency "bush welding" using two 12 volt batteries, a welding stick, jumper leads and wearing two pairs of sun glasses, my welds held but they were very sad - they resembled pigeon shit and that was an apt description.