Thread: Engine Saver

Originally Posted by waynep

If the alarm is constantly on, either the probe is not immersed in coolant, OR there is a break in the wire between the probe and the alarm unit. Are you sure the in line connector at the alarm unit end is fully pushed in ? Yes , checked this morning.

I topped up this way when fitting the engine saver in my D1 300Tdi. Worked fine for me.

1. fill reservoir to FILL mark.
2. engine off but on ignition setting - alarm should be on. ( no coolant in top hose )
3. remove fill plug on radiator - fill with coolant.
4. refit fill plug on radiator.
5. remove fill plug on thermostat housing - fill with coolant - alarm should go off as you fill. This is one step I missed , thanks Waynep
6. refit fill plug.
7. run engine for a couple of minutes.
8. if alarm goes off repeat above procedure.

If you re pretty sure the probe is covered by coolant there could be a problem with the probe or wire. I'd ring EngineSaver he's very helpful.

The above mentioned step "5 " is one I missed.

Remember that the above exercise is not an end in itself. Reckon I have a simpler, cheaper and more reliable setup on my 300Tdi to prevent engine overheating. Wire from ignition switch to fuel solenoid on the injector goes via temperature sensitive switch on the head. It opens, and the motor stops if the temperature reaches 105 degrees - well before it suffers any heat damage. Doesn't matter if the cause is sudden major water loss or the water just getting hot for some reason or combination of them without losing any.

Also most things that can go wrong with this system, eg if a wire falls off will also stop the motor. This makes it preferable to having things such as buzzers and warning lights that have to work properly to give protection.

The above temperature sensitive switch arrangement is particularly good for applications where diesels are left running unattended, eg driving pumps.

Hi Mox
The idea sounds good,but is quite dangerous.
I wouldnt like the motor just shutting down of its own accord,sure it may save the engine.Can imagine passing a roadtrain and having a shutdown.
If it looses the water suddenly it wont work until the engine is destroyed anyway.The temp sensor will now be reading heat soak that would have to be real high to hit 105deg at the temp sensor thats not imersed in coolant.
Andrew

hey mox this temp sensitive switch is it inserted into the cooling system or bolted onto the head.....

Ida thought that if it was connected directly to the metal of the block its heat up pretty damn quick in the event of coolant loss. Especially if it was on a bolt on the exhaust side of the head.

Pounds to peanuts an airlock. Make sure you quit all air from the system out of the fill plug on radiator. Squeeze top radiator hose to make sure. Also make sure Phillips screw head of sensor is on top of hose and you have not installed it upside down.

alright;

what Ever I tried didn't make the buzzer stop so there must have still been Air inside top radiator hose , so anyhow off I went for test drive , Geez that Damn Buzzer , I think I have partial loss of hearing should have disabled it ,but that's too smart for me, anyhow once the engine got nice and hot , Buzzer stopped sounding ,suspect Thermostat fully open and water flowing around inside keeping everything nice and cool , just one thing thou going around the corners the buzzer comes on okay no sweat , take corners with a nice Gentle Turn , oh it's followed by nice Gentle sound of Buzzer , not quite fullblast , driving around a few more K'm , Buzzer stops again , it was fine till I got home to my Driveway , the buzzer comes on again , I suspect the position where the sensor is vertically on top and 80mm away from radiator as per instructions is not the most Ideal place for it ??um being on the bend of the Top Radiator Hose , anyhow bleed the system , pour OAT coolant back in and get all bubbles out and replaced top radiator plug and go for another drive . the engine was already hot enough so didn't take long for Temp Gauge to register normal operating temp reading , Pushing vehicle Nice and hard to get Engine Temps up for testing ,the Buzzer stops ,TEMP Gauge normal Red LED went out , okay turn around and went back home , again as soon as I get to the drive way the buzzer is back on... anyhow I know the Cooling system works will continue investigating tomorrow...

G’day Landy Andy,
Regarding your speculative claim that the setup I explained of having a temperature sensitive switch is dangerous: This is to explain why it is not. Conversely, the “Engine Saver”and other protection devices that don’t work if components fail or electrical circuits are broken are dangerous. It is better to have the motor stop when it is not overheated if the protection device itself fails. Years ago a parts salesman told me he felt guilty having sold a Murphy “switchgage” setup that failed to function for some reason, resulting in a cooked motor.

Also, to ladas who thought the warning was a useful post, you live less than 50 km from me. Could show you the setup on my 300 Tdi next time I am over your way or if you come here could also show you the slightly more elaborate arrangements on two tractors and a header (ie combine harvester, which often run in severe conditions and are very prone to overheating.)

As these have mechanical fuel shutoffs, have fuel solenoids between secondary fuel filters and injector pumps. Also, something I have not yet got around to installing on my Land Rover – oil pressure switches that work the other way to those for oil warning lights. ie They switch off when below 10 psi or whatever else adjusted to

For the motor to run, of course the fuel solenoid has to have power to keep it open. For engine protection, if this is provided via temperature sensitive and oil pressure switches, the latter at least has to be bypassed for starting until the oil pressure builds up. Have heard of time delay switches being used, but regard the simplest and best is a push button bypass switch that you hold down while starting until the oil pressure builds up enough .
This bypass switch (best pushbutton so not accidentally left on and installed where it can be easily held down ) also overcomes scenarios such as the one Landy Andy suggested eg motor cuts out while passing a road train due to overheating – instead of a buzzer or light giving a warning.

As the head could get a lot hotter than 105 degrees before damaging itself, would not hurt running the motor for a short period – probably in seconds to drive off the road . I have had them go off on a header motor, including while under heavy load in hot conditions and radiator getting blocked with dust. Then just driven to where the radiator can be cleaned with the separator out of gear holding down the override button. In this situation, with load on the motor greatly reduced, coolant temperature quickly drops back to normal but it takes the switch much longer to reset unless quickly cooled by carefully pouring water on it.

Regarding the claim that if the water suddenly went, the engine would be destroyed anyway: Have never heard of this occurring and local tractor mechanics here who have installed lots of these temperature sensitive switches over more than 20 years would have told me if they ever came across it. The first thing that gets hot quickly if water is lost is the head and you have the switch, which is about the diameter of a $2 coin, attached to somewhere that will heat up rapidly if malfunction occurs, eg low down on the side of the middle of the head and with two electrical spade terminals protruding.\

If damage occurs due to rapid water loss in a hot engine and there is some form of engine protection so it is shut down quickly, the damage is more likely from cracking and /or warping from uneven cooling than heating to a very high temperature. Water circulation helps distribute heat from hot spots around. It is recommended that hot engines be idled enough before shutting off so hot spots in them equalize enough with surrounding area temperatures.

If water is suddenly lost from a motor, the considerable amount of metal in it may heat up quickly but it is not instantaneous. The switch would turn off when temperature is less than 20 degrees above normal .Heat conducting characteristics are also important. Provided a spot that will get hot is close, heating of where the switch is situated should not be far behind.

According to reports I have seen, VM diesels which were used in some Range Rovers and have separate heads on each cylinder are very prone to destroy themselves by overheating. Looks like having a switch on each head at less than $60 each would be cheap insurance.

Maybe some reader could give us figures on temperatures cylinder heads on motors have to get to before damage occurs if heated and cooled fairly evenly.

Also in case someone asks who supplies these temperature switches, the only place I have come across is Shepparton Speedo and Instrument Service (in Northern Victoria.).

Seems to me some people on this forum have become obsessed with low coolant monitors as an end in themselves rather than a means of hopefully stopping damage to motors by overheating. Maybe a bit like how apparently when jet engines first appeared, the development priority of some air force brass was better propellers, pistons etc for piston engines instead of looking at a different concept.

I also think it's important when bleeding from the rad plug, to position the vehicle so the offside is higher than the nearside & to have the rad at a high point, using stands or a slope.
In other words, get the rad plug at a high position to allow as much air as possible to emerge.

You may need to do this operation a few times as well.

I fitted an Engine Saver some months ago.