Overheating engine protection

I have a RedArc coolant alarm in the OKA.
EDIT: The probe is fitted to the radiator header tank.
Cheers,
Peter
OKA196 motorhome

nickb, I have a block temp alarm as well as a low water level alarm, https://www.vpw.com.au/parts/DC-1035 and https://www.fullwavemarine.com/tempgauge.html

My gold standard is:

1. An Engine Watchdog (tm) with the thermocouple bolted to a thermostat housing bolt. I have the audible alarm set at 10deg above what a big hill climb causes.

2. A Low Coolant level alarm grafted into the top radiator hose.

Monitoring block temperature is not great, the block has such huge thermal mass that by time its heated up enough to generate an alarm the cylinder head is well and truly cooked.

gET YOURSELF A SCANGAUGE OR AN uLTRAGAUGE. bEST UNITS OF THEM ALL...SO MANY THINGS THEY CAN MONITOR AND ALRMS CAN BE SET TO SUIT.

There is a very cheap LED gauge you can buy that is listed as "temperature controller." on ebay. Costing under $30
I had one on my D2 with the sensor on one of the thermostat housing bolts and it saved my engine when I had a leak occur on one of my hoses. I had to insulate it from ambient with some Blu tack LOL.
https://www.ebay.com.au/itm/387200769376?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D272500%26meid%3D7c394e35778445808d427007a3a4f794%26pid%3D101875%26rk%3D1%26rkt%3D4%26sd%3D166290787997%26itm%3D387200769376%26pmt%3D1%26noa%3D0%26pg%3D2332490%26algv%3DSimVIDwebV3WithCPCExpansionWith2ColRanker%26brand%3DUnbranded&_trksid=p2332490.c101875.m1851&itmprp=cksum%3A3872007693767c394e35778445808d427007a3a4f794%7Cenc%3AAQAJAAABMAIY39866gaArUjrJ%252B%252F5tyl1XplgQtYouv7uMlkdVwXQZowxSQSLtPSuwVlG33jyEO37maQCqcYAtj9fp%252FVdq5GNLyNb9TmFDQjloy17tfvyoD%252BqYiZ4P2GEbYsEJljCGi%252FBJydiNJlJE9Cyfl9PkV47ykOgt2e%252FaGoTWClT5yEN1FKxE42sa39MFntveiiLwbhkBVLn47aEH4%252BkqlnwKs6iZYoe%252Fbvgeomt9spwxEt6hj3ZphDQM5wX4toonKK1H7qE2U52JsUD0vYB0L6Nn6tXKvhzTGdpDU3zjDgbNxlueK5xoQaekx8ANDR6Al2mLRMqFfYAwW3Kws%252FTInrc2RZfJmFsbbVscgw%252BM0A%252Fv4qi7YeE%252FtpA4YOmoOrLUmcQpSLWFVCv6y9KvA7lAKSneFI%253D%7Campid%3APL_CLK%7Cclp%3A2332490&itmmeta=01J95A4THFK000VBKE25RC9069

Two aspects to this, slow overheat caused by high engine loads and poor cooling and fast overheat caused by a sudden lose of coolant.

Devices such as the scan gauge can pick up slow overheats but will most likely miss a fast overheat as the sensor relies on water temperature to operate it and if you have a sudden lose of coolant there is no water to operate the sensor.

To protect against fast overheat you realy need a lose of coolant alarm.

Nick B
Down low, on or in, the engine block is the worst place to have a sensor. Too late Mate.

Don't use engine more

Temp gauge in the dash hasn't let me down yet in the dozen vehicle's I've owned since 1985.

Slightly off topic..
In regards to the ranger engine and maybe a warning to others .
I can't say I wasn't warned of this problem I had seen this and heard of it many times before .
My thoughts was I would see warning signs before I.e the water level dropping or maybe temperature Rising before any damage my occur .
But was shocked to see how quickly it happened within 20 minutes of leaving
my house in the morning it was cooked
Interesting that Ford told me that it's not only the EGR problem but the head as well and can go within weeks of each other . I haven't got the final bill yet but just to fit a second hand engine it will cost me a minimum of 12 K imagine that if you were out bush and that happened

Cheers nick

I dont even trust factory temperature gauges in vehicles.. Toyota were fitting a zener diode circuit to their gauges in the 90s to lock the gauge in at a set point and hide the normal fluctuations. By the time the temperature had risen enough to cause the gauge to start moving again the head was often cooked, quite a disgusting design.

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Nick, Temperature gauges, no matter where the sensor is located, will not warn you when a catastrophic coolant loss occurs, such as a failed radiator hose, or a heater hose for that matter. Believe me, I know!
Even with a slow coolant leak and some resultant engine overheat, the OEM temperature gauge may indicate this but will you notice it without an audible alarm?

The most likely event to cause sudden overheat is loss of coolant level which first reveals itself in the radiator head tank. A coolant level alarm with audible buzzer is the only reliable way to monitor this. You will receive the warning even before the engine temperature begins to rise.

Redarc make such a device and as is usual with Redarc, it is of good quality. However it has no internal audible alarm so you need to supply and fit one of your own. It is also does not come with the required sensor electrode and is overpriced.
Davies Craig offer an essentially identical model but with an internal buzzer, comprehensive sensor and fitting kits, and at a lower price. That would be my recommendation.
I designed and built my own system but it does need some skills to do so.

I observe that people seem to focus on radiator hoses as being the risk component but the small heater hoses are just as vulnerable but invariably overlooked in maintenance.
Also, carrying spare hoses seems to be the norm, but they are only of value after the event of hose failure occurs. My practice is to replace all hoses, radiator and heater, each season. Not much trouble or cost and it avoided the crisis arising in the first place. Even then, I did experience a leak in a new bottom hose that only occurred when the system was at pressure. My alarm warned me before any disaster.

After coolant loss/overheating, not picked up by the temperature gauge in our bus, when we bought our Patrol I fitted one of these at what was just about the highest point of the coolant system. It's brief self test beep & red light flash each time I turned on the ignition was very reassuring over the next 10 to 12 years.

https://www.enginesaver.com.au/

I've read all the replies so far and it seems to me that everyone seems stuck on the similar path of water loss monitoring, but I'd like to suggest an alternative that was successful back in the 1970's for me.

The car I had then had issues with the electrical gauges and their reliance on a troublesome power feed. I decided to rip it all out and replace with a full set of Smiths gauges with some critical ones being mechanical for temperature and oil pressure etc. In doing the dash panel I ended up with a final space to fill. In looking through the Smiths catalogue I spied a possible answer to this issue of hose failure. It occurred to me that temperature monitoring was not the best due to the sensor when exposed by water loss would just read the air temp in the system. A water level sensor would mean that I had already lost a significant amount of water.

But this gauge was a mechanical pressure one. It took me a bit of trial and error to find a proper access point to monitor as a couple were in the pump suction side. It was working well, and I finished it up in time for a long interstate trip from Darwin to the east coast, down to Sydney and headed across to Adelaide. Halfway between Hay and Balranald the gauge proved its worth. I was lucky to be glancing at the gauge just as it suddenly went from its normal steady reading to near zero. A quick stop, lift bonnet and see a heater hose streaming water. Took me about 10 minutes to patch or bypass hose (can't remember which), replace minimal water loss and be on my way again.

The downsides to this particular gauge though is that a few months later the very small copper tube feeding it got blocked', and that it needed to have an audible alarm as well as visual.

Surely though there may now be some other type of pressure sensor that could achieve a similar but more reliable outcome. If there is, I'd buy it.