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Electronicsy guys??
owelly - 27/11/09 at 09:26 PM

Maybe because I'm a tight-arsed Yorkshireman or maybe because I like the idea of making my own......

Bongo Buses like the one I'm running and like the new one I've just imported from Japan, have an inherant problem. Dozens are written off due to coolant loss or engine overheating. The two are clearly linked and usually, the engine overheats because the coolant runs off or the engine overheats, pressurises the crumbling rubbish quality rubber hoses and they fail, causing the coolant loss. The first you know about it is when your Bongo goes pop. If your keen-eyed, then you will notice the temperature gauge drop as the coolant gets out and then rise slightly as the head starts to overheat but with no water in the system to make the temp sender hot. Whatever.........
You can buy one of these:
http://www.bongoforum.co.uk/factsheets/TM2_FINAL.pdf

But they cost money. Cheaper than a new head or engine but still not cheap. Remember, I'm a Yorkshireman!
And there's this to go with the above:
http://www.bongoforum.co.uk/factsheets/enginesaver_coolant_alarm.pdf



What I'd like to make, is a little unit that has a temp sensor bolted to the head, feeding several LEDs to depict the head temperature and another sensor to fit to the header tank to illuminate two LEDs to depict the alarm is working with enough water in and a flashing one to warn of impending doom.

Can you guys come up with anything??

Cheers in advance.


carpmart - 27/11/09 at 10:16 PM

Forgive me for being simple but why not fix the problem and put new silicone hoses on the vehicle?

Your solution is just diagnostics of the problem when it inevitably happens, new hoses is a fix!


MakeEverything - 27/11/09 at 10:25 PM

quote:
Originally posted by carpmart
Forgive me for being simple but why not fix the problem and put new silicone hoses on the vehicle?

Your solution is just diagnostics of the problem when it inevitably happens, new hoses is a fix!



Ditto.

Solve the problem, not the symptom....


turbodisplay - 27/11/09 at 10:37 PM

as above best bet is fix the problem. If you still want to have a warning i think a pressure sensor, as well as a temp sensor in the coolant would work.
A leak will result in a loss of coolant pressure.
Darren


owelly - 27/11/09 at 10:40 PM

If only it was that simple....
I fitted new hoses to my current Bongo but the rear heater matrix sprang a leak. And whilst I was under the car fixing it, I noticed the steel pipes to the rear of the vehicle were also corroded. I replaced them with copper but there are loads more rigid and flexible pipes around the engine bay, up inside the side panels and under the van that look to be ok but so did the matrix............


gazza285 - 27/11/09 at 11:04 PM

Why not just fit a coolant level senser? I can't remember which motor, but either my Berlingo or Volvo has one, probably the Volvo though.


MikeRJ - 27/11/09 at 11:12 PM

Cheap panel mount digital thermometer? You could at least measure head temp with that.

Or use a temperature switch as BT suggested a while back?


MakeEverything - 27/11/09 at 11:30 PM

Or get rid of the rusty old thing and replace with something a little more reliable!


RK - 28/11/09 at 03:56 AM

Ha! I ordered 10 of those NO switches as BT suggested, set for 100c. Can't wait to install it and get rid of my water temp gauge.


rusty nuts - 28/11/09 at 07:16 AM

Have a look at British Tridents overheating warning system , he posted it a few weeks ago . Note to myself, must learn how to put in link.!


r1_pete - 28/11/09 at 08:32 AM

The ford zetec has a casting temperature sensor screwed into the head, I dont think anyone uses them, I binned my 2 or you could have had them, but someone on here should have one you can have cheap as a start....


02GF74 - 28/11/09 at 11:45 AM

simples - what you are asking about is a comparator circuit.

the temp sender is effectively a resistor whose resistance varies with temperature.

you would wire up comparator circuit so one input is the sender and other is fixed value resistor, the resistance being equivalent to a specific tepperatorye.

once the sender resistance is above/or below (depends on how you wire the circuit) the comparator will flip output so can light up a lamp, otherwise lamp is off.

you need to calibrate the sender to know what resistance corresponds to what temperature.

pretty sure you can get 4 comparors in a 14 pin DIL psackage so can with just 4 resistors, monitor 4 different temps.

if you need help with the circuit, and then making it, let me know.

maplins make
this but it is rather pricey and may not work without modification with your sender.


here you are:

This circuit can sequentially indicate 4 separate voltage levels. The voltages are determined by the values of resistors R1 through R5 arranged in a simple voltage divider circuit.


[Edited on 28/11/09 by 02GF74]


BenB - 28/11/09 at 12:15 PM

Easy peezy. Couple of thermistors, each as the top half of a potential divider to give a voltage proportional to temperature and some comparators and job's a good 'un. Simplest option for the flashing red is led is just to buy a flashing led....
Total cost = £10.


greglogan - 28/11/09 at 04:31 PM

Owelly

you have one of the most questionable tastes in vehicles that I have ever come across. Just don't make me read about the Bongo ic PPC - please!!!

Anyway, have a lookat the link below. I've use these before and with a bit of work, you can have it trigger a lamp/buzzer via a relay when certain temperature limits are exceeded. Hope this helps

Greg.

Tempy linky thingy


owelly - 28/11/09 at 10:53 PM

Cheers guys.
I'll ahve a crack at building the comparator thingy. I have my slobering iron out anyway.........


And what's wrong with my taste in vehicles???