Towing a caravan

[helen&tony]

Hi
You're nor coming near me with that thermometer, nurse Mike
Cheers
Helen

[haydn callow]

There have been cases reported of Bongos overheating through lack of coolant when in fact the Bongo gauge reads lower than normal or Zero....this is because when coolant is lost it empties from the top down....the Bongo sensor is at the top of the system and need to be immersed in coolant to work. So if you fit a alarm that takes it's info from the Bongo gauge it could be that nothing would happen if overheating took place due to coolant loss.....Swings/roundabouts I'm afraid. The TM-2 mentioned above reads the "metal" temp of wherever you position it....If you wanted to read the actual coolant temp then the nearest you would get would be by bolting it to the thermostat housing. What must be remembered is that assuming your bongo is in good condition and running well...all you need to be looking for is what is not normal...so....wherever you take the temp is fine.....by observing what is the "highest" "normal" temp over a period of time and then setting the alarm to "alarm" a few degrees higher it will always give you plenty of warning when the "not normal" happens.
The low coolant alarm (totally differant system to the TM-2) warns you of any small loss of coolant from the header tank....LONG BEFORE any rise in temp takes place and often a quick fix can be worked out and carry on with your trip....If overheating happens due to coolant loss (no low coolant alarm fitted) most of your coolant will have gone and so much more hassle at the road side (repair/fill up/bleed).....Top Tip....Fit a low coolant alarm first and then if funds allow a high temp alarm or a combination of both.

[Doone]

The low coolant alarm (totally differant system to the TM-2) warns you of any small loss of coolant from the header tank....LONG BEFORE any rise in temp takes place

I heard a whistling noise from the centre of the dash (expansion bottle area!) The noise got louder and the temperature gauge immediately rose to 1 o’clock… It was dark and I was in heavy traffic so I had to drive a few hundred yards before I could safely stop. Within that short distance, I heard water boiling under the passenger seat area. This got louder, gurgling and banging as it errupted through the expansion bottle.

Haydn, I think I remember reading that you were modifying one of your alarms, so it would identify a problem in the above situation (where the temperature gauge rose BEFORE loss of coolant). Have you done this yet? If so, which of the alarms does the 2 jobs (shows the coolant loss before temp rise, and shows a temperature rise before coolant loss). Or are they 2 seperate alarms? Thanks (I have also pm'd you).

[mikeonb4c]

We already do have a recommended position and we provide a correct sized bolt.

However as I say earlier...when towing this position does read a high temp.

So that would be exhaust side that is given out as recommended then?

I wonder if there is any other position the device could easily be adapted to and that would allow it to give readings less influenced by thermal capacity and conductivity of the block, ambient air etc. I wonder whether something like a modified sump plug with probe might make a good (theoretical - practical issues are something else) sensor position as it could measure the temperature of the oil

[mikeonb4c]

There have been cases reported of Bongos overheating through lack of coolant when in fact the Bongo gauge reads lower than normal or Zero....this is because when coolant is lost it empties from the top down....the Bongo sensor is at the top of the system and need to be immersed in coolant to work. So if you fit a alarm that takes it's info from the Bongo gauge it could be that nothing would happen if overheating took place due to coolant loss.....Swings/roundabouts I'm afraid. The TM-2 mentioned above reads the "metal" temp of wherever you position it....If you wanted to read the actual coolant temp then the nearest you would get would be by bolting it to the thermostat housing. What must be remembered is that assuming your bongo is in good condition and running well...all you need to be looking for is what is not normal...so....wherever you take the temp is fine.....by observing what is the "highest" "normal" temp over a period of time and then setting the alarm to "alarm" a few degrees higher it will always give you plenty of warning when the "not normal" happens.
The low coolant alarm (totally differant system to the TM-2) warns you of any small loss of coolant from the header tank....LONG BEFORE any rise in temp takes place and often a quick fix can be worked out and carry on with your trip....If overheating happens due to coolant loss (no low coolant alarm fitted) most of your coolant will have gone and so much more hassle at the road side (repair/fill up/bleed).....Top Tip....Fit a low coolant alarm first and then if funds allow a high temp alarm or a combination of both.

I should have made it clearer - it is the principle of measuring somewhere least affected by unpredicatble effects that I was putting up for consideration, not the (well understood by many on here) risk of relying on the standard sensor probe to warn of overheating.

In practice, you would have your LCA to warn of coolant loss. As long as that hasn't gone off, then it is all but certain that your standard sensor remains immersed in coolant and gives a readout that can be trusted.

What we're trying to achieve is a situation not just where each owner is able to spot something abnormal happening to their Bongo (e.g. " it never used to get to this temp going up this hill") but where one Bongo owner is able to say to another (new) owner "you shouldn't be getting a reading of XXX degrees cruising on the flat at 25000rpm as the range for a healthy Bongo is YYY degrees". To do that with confidence you have to work hard on finding a way of taking the temperature that will not be affected by unpredictable variations.

[haydn callow]

Doone....we have a "Hi coolant " add on which involves putting a "screw sensor" in the top of the expansion tank. (just in the neck below the filler Cap)

this then simply "plugs" into the "already" fitted Low Coolant Alarm.

This will detect when the coolant in the tank "bubbles" up and starts to spit out. It just helps a little bit more in some possible cases.

[Doone]

Thanks Haydn. If you ever design one that stops it bubbling like a volcano under the passenger seat, let me know! Quite an experience!