Low Coolant Level - Mod for reservoir bottle or even the rad itself?

[MisterCruiser]

Has anyone done a mod for adding a low coolant level on their Landcruiser, either a 90 or 120 series.

I had to top the rad up by 1.5L today. My reservoir bottle is always empty, so not much point putting the level in their I suppose although it would be good to have it there if Landcruiser's ran a pressurised expansion bottle like modern cars. Whilst, my over flow is nearly always empty, my rad is always full to the brim, in 10yrs of ownership. Until today, when the rad needed 1.5L. I had a quick look and don't think there is a leak, this cruiser doesn't get used much anymore but the coolant still shouldn't just disappear I suppose, so I'll keep an eye on it.

So I guess the next obvious place to put a sensor would be in the rad itself.

Has anyone done such a mod? Or is there some other location to put a sensor?

My German car with a pressurised coolant reservoir has a low level warning and it saved me one time a hose sprung a leak on the way home from work. It's mad to think there is no warning on the landcruiser. You could have a hole in your rad from a stone or such and be losing coolant on a long trip and not even realise until your engine is over heated.

 

[Towpack]

If the expansion tank is always empty and now the rad needs topping up you must have a leak somewhere, either that or it's losing it through the head gasket and being burnt off in the combustion chamber when the engine is running but that would be pretty obvious. Fitting a coolant level sensor somewhere in the system may well alert you to coolant loss but it's not fixing the cause. If there are no obvious leaks I'd get the system pressure tested.

 

[MisterCruiser]

I'm not worried about the overflow bottle always being empty, I fill it up and over time it always empties. It has always done this and never over heated, etc,, I have read of other Toyota folks having this strange situation with no issues, seems normal for some of these vehicles. It came up in a thread possibly on here, yrs ago, some lad with a Dyna had same situation and seemed normal for his yoke.

This has been normal for my 10yrs of ownership. What hasn't happened before is topping up the rad. Heater still works fine, temp gauge sits normal, no sign of leaks, no coolant in the oil, mine is a SWB manual, so no auto pipes or rear heater, etc... No leakage on the ground underneath where it could be parked for a month at a time. Rad and rad cap is fairly new, water pump replaced in recent yrs too, hoses that I can see easily seem ok.

There actually aren't that many hoses to leak from, top + bottom rad ones can be easily seen and are short, heater hoses are easily seen too, not many other hoses, metal hoses that the heater ones attach to at the back of the engine, unless they're rusted or something. Compared to other cars that have coolant pipes and hoses everywhere around the engine the crusier seems to have few.

Don't think it's burning it, no smokier than normal, etc...

I'll keep an eye on it but I's like to have a low level warning in the rad or somewhere, is it possible to fit one in somewhere?

 

[Shayne]

Its a different angle on the common suggestion to add a temperature gauge because the factory gauge has only 3 positions off , normal and cracked head .

 

[Shayne]

If bottle is always empty I'd get a new radiator cap first and foremost . Took me a long long time to work out my leak was a pipe dripping directly onto the turbo so instantly vaporized leaving no evidence to find .

 

[Towpack]

Every coolant level sensor I've come across has been fitted in the expansion tank, either the float type or contact type. Such a sensor in the rad wouldn't work well in the rad IMO due to the flow.

 

[MisterCruiser]

Every coolant level sensor I've come across has been fitted in the expansion tank, either the float type or contact type. Such a sensor in the rad wouldn't work well in the rad IMO due to the flow.

That's the only place I have seen them too, but that's ok on a modern car using a pressurised reservoir and not an over flow bottle like ours. With the bottle constantly rising and dropping under normal operation the level sensor is no good in there.

@Shayne - I don't agree the sensor hs only 3 positions, mine makes it's way up to normal gradually on the gauge, it doesn't go from o degrees to 90 in one movement.

I suppose the only other place to put a level sensor would be in a top hose or something, but how would that go practically i wonder

 

[Shayne]

OK to say it a different way if you were to lose all your coolant your engine would be cooked before you noticed the factory temperature gauge had moved .

I'm sure i bought a gauge that changed colour at a set temperature which was to be coupled with a sensor in the top radiator pipe but felt i didn't need it after fitting a 3" turbo back exhaust .

Alternatively you could put one of those loop to a bolt sensor gauges in the bottom third of your radiator which should typically show much cooler than the factory gauge , if coolant was low that would show hotter than usual .

 

[MisterCruiser]

TM2 Engine Watchdog - Digital Temp Gauge with Alarm - Full Wave Marine - [Leaving Land Cruiser Club]

I came upon this electronic temp sensor, anyone got experiencer thoughts of 1 of these?


Or this screw in type suitable for Landcrusier rads with their coolant bleed screws. Does a landcruiser rad have a bleed screw fited, I can't remember when replacing mine.

Low Water Alarm Sensor - [Leaving Land Cruiser Club]


And this other inline hose sensor
Coolant Level Sensors | CARTEK Motorsport Electronics - [Leaving Land Cruiser Club]

 

[Aeroelastic]

Has anyone done a mod for adding a low coolant level on their Landcruiser, either a 90 or 120 series.

I had to top the rad up by 1.5L today. My reservoir bottle is always empty, so not much point putting the level in their I suppose although it would be good to have it there if Landcruiser's ran a pressurised expansion bottle like modern cars. Whilst, my over flow is nearly always empty, my rad is always full to the brim, in 10yrs of ownership. Until today, when the rad needed 1.5L. I had a quick look and don't think there is a leak, this cruiser doesn't get used much anymore but the coolant still shouldn't just disappear I suppose, so I'll keep an eye on it.

So I guess the next obvious place to put a sensor would be in the rad itself.

Has anyone done such a mod? Or is there some other location to put a sensor?

My German car with a pressurised coolant reservoir has a low level warning and it saved me one time a hose sprung a leak on the way home from work. It's mad to think there is no warning on the landcruiser. You could have a hole in your rad from a stone or such and be losing coolant on a long trip and not even realise until your engine is over heated.

@MisterCruiser if it needs top up 1.5litre, it is leaking somewhere. It probably make sense to find the source of the problem than fitting a sensor to tell you when coolant is low.

When the engine warm up, is there any coolant in the expansion tank? If not then the rad cap is likely the culprit, but not a 100% foolproof check.

The 1KZ TE can run with head issue for a while before things really became obvious. From my own experience, I have run mine for more than 6 months while it has head issue (porous head above inlet port – not cracked head), and it never show any sign of expansion tank overflow, overheat etc. The only sign was I have to top up coolant every few weeks, by about 0.5litre. and also first start in the morning, there is a puff of whitish smoke, but then not an issue for the remaining of the day.

If there is no visible leak, then likely coolant is escaping from burning, or have you checked leak (heater Matrix) in the cabin near passenger footwell? Or around the turbo pipe area (water cool turbo)? But this is likely to evaporate quickly as Shayne said.

There is 1 test that will almost confirm if there is head/gasket issue if there is no external visible leak, the compression test (the one with a pump and a cap that connect to the top of your radiator) easy 5 mins job if you have the tools.

 

[Shayne]

The second link is the same kit as the first i think , i looked for similar a good while ago and i think they were circa £150 .

The Cartek one I'd expect to be stupid money , bloody frustrating because all i wanted , all anyone needs is a light that comes on when your engine hits 90 degrees .

Not sure but I think a standard thermostat opens about 84 degrees .

And yes the turbo is water and oil cooled .

 

[Shayne]

Should you lose all coolant while driving do not put cold water into a hot engine , it will crack . And if your overheating don't shut your engine off , pull over and let it tickover so it can circulate coolant , if your on a motorway and can't stop then 5th gear tickover in the slow lane .

Memory is vague but Beau lost his 1kz coolant while driving and I can't remember how or why , might be worth searching the forum for his thread .

 

[MisterCruiser]

My cruiser isn't leaking, it's just it does be sitting up for most of the winter and only doing circa 1000 miles in the entire year for the past 5 yrs. The coolant just evaporated or such, I have topped up the overflow and the rad and it's fine since.

The cartek one or it's type seems the best option, easiest to fit too. Why does it detect air though and not coolant, is it because it's too difficult to get a coolant sensor to differentiate between fully emerged in coolant and only a few drops of coolant on the sensor when empty? Would a couple of drops or traces of coolant on the sensor after the hose with the sensor has emptied be enough to trick the sensor into thinking it was detecting coolant and not indicate a problem?

Is any member here running such a sensor as the Cartek type?

 

[MisterCruiser]

What's the little "spout" for on the overflow bottle cap as pictured, the blue drawing indicates the hole is connected to the spout, water can flow from the hole in the rubber to the spout, I assume this is an "overflow" if the bottle fills up to the brim, but how would that ever happen, it'd take litres for the fluid to reach the cap. Or is that for if you have a serious issue like exhaust gases leking into the coolant from a cracked block or such which would pressure the coolant back into the overflow bottle?

 

[Ben Stratford]

I thought the overflow bottle should fill via a tube from the underside of the cap??
In such a scheme the liquid can get drawn back into the radiator to maintain level.
Without the tube the expansion bottle can overflow and the whole system gets depleted? Here’s a pic of my arrangement if it helps

 

[Towpack]

The "little spout" in the cap and the short pipe in the photo on the last post are primarily to let air out as well as excess coolant in the unlikely event the tank overflows. The coolant level in the tank will rise and fall according to engine temperature, filled and drained by the long tube (the end of which must always be below the coolant level) on the cap but the tank itself isn't pressurised so air must be allowed to flow freely in and out, just like air must be allowed into the fuel tank as the fuel level goes down.
MisterCruiser, you must have a leak somewhere, you just haven't found it yet. The system is sealed so coolant cannot just evaporate.

 

[Shayne]

Hope it’s not an auto because the radiator also cools gearbox oil and it’s a know problem when the radiator corrodes internally it can mix oil and coolant . Sat idle for months on end I would suppose there is no oil in the radiator giving coolant somewhere to go

 

[MisterCruiser]

The "little spout" in the cap and the short pipe in the photo on the last post are primarily to let air out as well as excess coolant in the unlikely event the tank overflows. The coolant level in the tank will rise and fall according to engine temperature, filled and drained by the long tube (the end of which must always be below the coolant level) on the cap but the tank itself isn't pressurised so air must be allowed to flow freely in and out, just like air must be allowed into the fuel tank as the fuel level goes down.
MisterCruiser, you must have a leak somewhere, you just haven't found it yet. The system is sealed so coolant cannot just evaporate.

So the little port in the cap is for air mainly, Thanks for clarifying.

Mine is a manual short wheel base, so no auto leak contamination to worry about or rear heater pipes. I'll drive it more over the next week and keep an eye on it.

I'd still be interested to hear from any member here running such a sensor as the Cartek type?

 

[Shayne]

Get your heater blowing hot and then top up , you can't fill heater pipes without running the engine and thats easy 1.5l

 

[MikeJak]

on the 90 series is quite common for the rear heater hoses to perish and leak small amounts of coolant so if you're losing coolant but oil looks good and exhaust doesn't smell of coolant/ smokes white I'd have a look under there.
regarding a sudden total coolant loss warning the only meaningful system on our engines with a non pressurized expansion is an in line contact. I had bounced the idea with a friend, basically add in the top hose a fitting with a capacitance sensor, circuit wil be closed when coolant is in the hose, if no coolant the contact will be open and you can make it so it triggers whatever sort of alarm you want it to, a bright led or a buzzer. I did get some parts for it but not finished it.
there are also no contact level sensors but they are mostly for pressurized expansion tanks... so no good.
I think the engine watchdog type systems would just let you know once you have overheated the engine already...