TEMP Alarm Sensor Position

[mikeonb4c]

I think some sort of audible/visual "abnormal temp" alarm would have to be built in for the average user.

Definitely. No sensible person is going to be more interested in watching their gauge than the road. The beep will remind you though to glance at the gauge and note the figure. Over time you'll get to know normal and abnormal values (well sort of). I presume the TM2 has a knob that is readily accessible (while driving?) and allows the alarm threshold to be moved.

If I do anything, I think I may still head down the oil temp route though, as it interests me and it ought still to be a viable alternative. Just need to identify how I can easily tap in to take the oil temp

[Roberus]

Going back to the original post I've now moved the sensor and readings appear to be approx 10 degrees lower. Simple job too. Cheers for the post Haydn.

[haydn callow]

Thats great....thats the response I was looking for at the start of this topic. If we all switch to there we should get some more meaningful readings. It's only a 30 min job and should prove benificial.

[Roberus]

As a matter of interest what sort of temp reading should we be getting? In the previous position it sat at about 93 all day but increased to +105 if going up a steep incline (anyone know Telegraph Hill?). It's only day 1 of the new position (ooer missus!) but as I said looks to be approx 83 but will post more readings once I've had the chance to run her for a few more miles.

Cheers!

Rob

[haydn callow]

drive around for a couple of weeks and note the highest temp reached....set your alarm a couple of degrees higher..
I will report on what mines reading...if you do the same and there is at least one othet.....we should get some meaningful readings between us.....anyone else with a TM-2.....if you move your sensor to this position then that would be good

[francophile1947]

If I do anything, I think I may still head down the oil temp route though, as it interests me and it ought still to be a viable alternative. Just need to identify how I can easily tap in to take the oil temp

I really think you'd be wasting your time and money Mike. Remember when we were young (and the old bangers we drove had just a fuel gauge and the odd warning light) we used to fit gauges for water temp, oil temp, oil pressure, ammeter and vacuum. The oil temp gauge hardly ever moved, even though the water temp was up and down like a yoyo. I can see it may be of benefit in an air cooled engine, but the coolant would have boiled long before the oil temp rose by much.

[mikeonb4c]

If I do anything, I think I may still head down the oil temp route though, as it interests me and it ought still to be a viable alternative. Just need to identify how I can easily tap in to take the oil temp

I really think you'd be wasting your time and money Mike. Remember when we were young (and the old bangers we drove had just a fuel gauge and the odd warning light) we used to fit gauges for water temp, oil temp, oil pressure, ammeter and vacuum. The oil temp gauge hardly ever moved, even though the water temp was up and down like a yoyo. I can see it may be of benefit in an air cooled engine, but the coolant would have boiled long before the oil temp rose by much.

I probably would be as (fingers crossed) I appear to have a healthy Bongo. But I suspect un unhealthy one might run a higher oil temp than a healthy one. Overall, I will probably save my money for summat else. Its good that TM2 owners look like standardising the position of their sensors, as that should improve the comparability of results. I'm still interested in oil temps though - sorry!

[The Great Pretender]

Good luck Mike, I fitted the digital gauge that I posted in your oil thread. The response time for ordinary gauges is dismal compaired to the thermistor in the coolant that I have been using.
Haydn, the reason your reading lower temp from the rear of the head is because it is the coolest part of the head. Inlet side and reading from coolant rising from the block.The coolant rises from the block to the head, the block transfers only a small amout of total heat into the system. As the coolant moves towards the front of the head it gets hotter as it needs to remove the heat of the 'bang'.The piston uses as much energy as it can, the rest is dumped into the exhaust, so where is the hottest part of the engine? It has to be exhaust side of the cylinder head and now it gets intresting, where normally is the hottest part of the head, where does it crack?

[Aethelric]

TGP, would you expect the coolant to get hotter and register a problem if the the overheating problem was caused by air trapped in the head (due to poor bleeding)?
Is a cracked head the result of overall overheating or the differential between the sections on the head cooled by flowing coolant and trapped air? If the latter, then the best position for a sensor would be on the part of block that is closest to where air pockets form. Just a thought!

Dave

[The Great Pretender]

TGP, would you expect the coolant to get hotter and register a problem if the the overheating problem was caused by air trapped in the head (due to poor bleeding)?

Yes because the coolant is there to react to the heat produced by the engine, if the head is half full of air there is only 50% coolant that needs to try and remove all the heat so the temp will rise most at the outlet of the head.

Is a cracked head the result of overall overheating or the differential between the sections on the head cooled by flowing coolant and trapped air? If the latter, then the best position for a sensor would be on the part of block that is closest to where air pockets form. Just a thought!

Dave

Heads crack, some do some don't, normally at high milage.
Air pockets can't form in a well engineered cooling system as they will end up in the header/expansion/degassing tank.
If you think about what is the cooling system hardest problem it is removing the heat from the hottest part of the system, that is the area around the exhaust valve. What can and does occur there is gas pockets caused be the coolant boiling, then localised overheating and thermal stresses leading to cracks forming, and where do they crack? Normally close to the exhaust valve.
As you know I covered this before and the thread was shut down so i'm not going to cause another riot. All I will say is the Bongo has two design faults with the cooling system and both of them are covered above.
Any air that gets into the head struggles to vent to the rad due to the engine position and very difficult to resolve. The thermostat is in the wrong position and leaves the head prone to localised overheating and easier to resolve.

[cheffy34]

At last i understood that straight to the point



Dar

[The Great Pretender]

At last i understood that straight to the point



Dar

GREATTTTTT, can you explain it to me....................................

[cheffy34]

What and teach you to suck eggs not that brave sir


Dar

[The Great Pretender]

I don't remember posting it..................

[cheffy34]

I don't remember reading it