Temperature Guage

Bongobus · Post by **Bongobus** » Mon Dec 10, 2007 10:46 pm

Alooo bongoliers - Since fitting a mason alarm, changing a perished hose above starter motor, flushing old antifreeze out replacing the antifreeze and after successful bleeding (I think) - my temp guage needle is very low when first started and as normal raises. When i drove vehicle around town was around the first mark as per the image for good 30mins, i then decided to put pressure on the vehicle and went for a uphill motorway hammering - this raised to the total max and alarm kicked in.

So - I stopped vehicle and bleed more scalding steam (with air-I believe) from bleed pipe until i had fluid.

What I have now is when the vehicle is hot readings as per the image - fluctuating between the 2 markers i have drawn - When near the highest marker it then lowers after the vehicle is driven level ground etc which i assume is when the thermostat opens . I havent gone for the motorway uphill blast yet though!

Question is:- Is this normal now with this mason alarm e.g others getting this reading too or am I now just being paranoid.

haydn callow · Post by **haydn callow** » Mon Dec 10, 2007 11:07 pm

I would be suprised, if after your engine is throughly warmed up, the thermostat opens/closes. I would think it remains open .
Check your bottom hose is warm to the touch after a good run. It should not get to hot to grip.

madmile · Post by **madmile** » Mon Dec 10, 2007 11:16 pm

I must admit, I have never had a bongo go anywhere other than between the 11 - 12 O'clock position - except perhaps for a few minutes when you are bleeding. I am not familiar with the mason alarm, but surely it would not affect the standard needle position.

daveblueozzie · Post by **daveblueozzie** » Mon Dec 10, 2007 11:17 pm

The mason alarm does indeed give a greater reading on the temp guage, as you said it rises then lowers as you ease off the power.
Mine was usually about the eleven o'clock position on the gauge,
but it now rises to about one o'clock with the mason alarm fitted , and have seen it rise to nearly the red zone with heavy driving.
The mason alarm on mine is set about 5 ish and have had no probs .

dandywarhol · Post by **dandywarhol** » Mon Dec 10, 2007 11:51 pm

Ditto times 3 Bongo Mason alarms I've fitted................

madmile · Post by **madmile** » Tue Dec 11, 2007 12:00 am

I didnt realise that the mason alarm interacted with the temp guage

.

daveblueozzie · Post by **daveblueozzie** » Tue Dec 11, 2007 12:12 am

The mason alarm has three wires that you fit onto the back of the temp gauge (3 screws 2 minute job) so it then gives the gauge the greater reading than it had before.

bigdaddycain · Post by **bigdaddycain** » Tue Dec 11, 2007 2:03 am

Instead of it reading a constant 11 o clock, the temp gauge actually moves in tempo with the coolant temperature.

One adjusts the settings of the alarm to compensate for the high (red zone) readings.

i.e. if the alarm sounds at the end of a mile long ascent,the adjuster can be moved on the control box from say 4 to 4.5.

Dave Mason · Post by **Dave Mason** » Tue Dec 11, 2007 11:16 am

madmile wrote:I didnt realise that the mason alarm interacted with the temp guage .

Yes, the M-alarm (http://www.townace.plus.com/ie/ietemga2.htm) has two separate functions.

When the temp gauge rises to the point where it used to stop (say 90degC - I have no way of knowing real temperatures) the M-alarm switches in a shunt resistance to draw a little extra current through the gauge AS IF the engine had suddenly got a bit hotter (say 115degC). This extra current is designed to get the gauge instrument to continue moving smoothly upwards without you having to wait for the engine to overheat. Without the M-alarm the gauge instrument would not move while the temperature rose from 90-115degC, or whatever the real temperatures are.

The second function is to sound the audible alarm - to draw your attention to the gauge - when the instrument goes past the point that you choose to set the alarm. The scale around the adjuster for setting the alarm is no more than a guide - in the same car two M-alarms might differ in their alarm point setting by as much as one division on that scale.

If both these functions suggest that your M-alarmed Bongo is getting hotter than everyone else's does, or than yours used to - i.e. the gauge is rising higher AND the alarm has to be set significantly higher - then it probably is. If you can swap in another M-alarm (there's a quick-detatch connector inside the box, you don't have to do it behind the dash) you could eliminate that misbehaving but I'm very confident that it won't be.