Thread: Drilling coolant reservoir for Engine Saver alarm

Originally Posted by roverrescue

At full noise down the road
A blown hose say at the radiator outlet (can be top or bottom depending on model) will empty the tank before the level in the inlet drops as the pump will fill the system FROM the tank.

Does the pump draw from the tank ?
The hoses to/from the tank are smaller diameter so if a radiator hose blows there would be a lag before the level in the tank dropped wouldn't there ? May be fractions of a second but there would be a lag.

I get the feeling that either location will give a warning within fractions of a second of one another. The bonus with the tank sensor is that you can be lazy and not physically bother to regularly check the level.

Back to an earlier question, does a tank sensor trigger when offroading ?


Colin

I put the float in the mid point on the side of the tank about 1cm below “full” level

Never had a false alarm

But it has given me warning of fluid leaks (minor as well as HG Leaks)

Never have had a catastrophic dump of coolant in a landy

S

Does the pump draw from the tank ?

YES.
The expansion tank is also a coolant reservoir and as such it is designed to add coolant to the system in the event of a loss of fluid in the system.

I get the feeling that either location will give a warning within fractions of a second of one another. The bonus with the tank sensor is that you can be lazy and not physically bother to regularly check the level.

In the event of a small leak the sensor in the tank will give you plenty of warning, This is Not the case with the sensor fitted to the bleed hole/engine block because the sensor in the tank will warn you BEFORE the actual cooling system gets low on coolant.
In the event of a fully burst hose or any other catastrophic coolant leak it is a moot point where the sensor is fitted.
Anyone who doesn't check their fluids and the engine bay on a fairly regular basis IMHO has no business driving off road in the first place

Back to an earlier question, does a tank sensor trigger when offroading ?

On road, off road, uphill, downhill it makes NO difference .
If the sensor is fitted correctly the truck will have to be on its side to set off the alarm in the tank and if this is the case you ain't going anywhere in a hurry.
I have had my D2a on some crazy angles off road and the alarm in the expansion tank has never triggered.

The D3/4 has a level float in the expansion tank.
It never came on no matter how much of an angle the vehicle was on.

But for some reason they liked to fail after a coolant flush.

The electronic temperature gauge in the dash of the D2 is pretty useless, as once it gets up near the red, the engine is already damaged.
This is why an 'engine saver' is essential.

Originally Posted by trout1105

YES.
The expansion tank is also a coolant reservoir and as such it is designed to add coolant to the system in the event of a loss of fluid in the system.



In the event of a small leak the sensor in the tank will give you plenty of warning, This is Not the case with the sensor fitted to the bleed hole/engine block because the sensor in the tank will warn you BEFORE the actual cooling system gets low on coolant.
In the event of a fully burst hose or any other catastrophic coolant leak it is a moot point where the sensor is fitted.
Anyone who doesn't check their fluids and the engine bay on a fairly regular basis IMHO has no business driving off road in the first place



On road, off road, uphill, downhill it makes NO difference .
If the sensor is fitted correctly the truck will have to be on its side to set off the alarm in the tank and if this is the case you ain't going anywhere in a hurry.
I have had my D2a on some crazy angles off road and the alarm in the expansion tank has never triggered.

I get the impression that the only advantage to a header tank sensor is the earlier warning if there is a slow leak.
If the level drops to the point where a radiator/block sensor triggers you're still going to get a warning in time to save the engine. Temperature may have risen slightly because less fluid in the system but with the block & radiator almost full still it shouldn't be an issue.

I've run for 20 years with no low coolant alarm and a black header tank (which I'm constantly told could split at any moment ?!). I'll fit a sensor at the top of the radiator and the Alisport tank then at a later date consider a header tank sensor.


Colin

I had the Jaycar float switch drilled into my expansion tank on the back of the tank. I had it for many years.

Problems :

• Under heavy braking or steep descent it would buzz due to the coolant shift. This was due to the position I had it in.
• The seals would perish after about 4 years (I always kept a spare in the cubby box).
• If you knock it while reaching into the engine bay, it's prone to break.

I've since replaced it with a RRC Expansion cap with a float switch.

The expansion cap closes the circuit when it's full and goes to open circuit when it's empty. The easiest way to wire this up is to use a double throw relay. When the relay switch circuit is powered (by the complete circuit through the cap sensor) the relays supply circuit is disconnected and when the relay is unpowered the supply circuit closes and provides power to the audible alarm.

Shortly after fitting it I had a radiator hose failure, and it worked well, I could pull up and there was still water coming out, no engine damage. It will also warn you of a drop in coolant level over time.