How "HOT" does it have to get ???

[mikeonb4c]

Hi Guys,
Mazda and other Japanese car manufacturers doctored temperature gauges by fitting a Zener diode.
By removing the Zener and a resistor,and fitting 2No resistors the gauge will work as it should.

Cost of resistors about £1.00.

Malc..

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Hi Guys,
Mazda and other Japanese car manufacturers doctored temperature gauges by fitting a Zener diode.
By removing the Zener and a resistor,and fitting 2No resistors the gauge will work as it should.

Cost of resistors about £1.00.

Malc..

Factsheet Factsheet We Want a Factsheet

Si desidera in italiano?

[Simon Jones]

£1 per resistor? I remember when they were 3p each from Maplins .

I'm led to understand that the exhaust manifold & pipe are a key part in the cooling system by acting as a heatsink to take the hot gases away effectively. So, the fact that side of the engine is hot is probably a good thing. A friend of mine has Vespa scooter to which he fitted a swanky stainless steel exhaust. It would run great until he went for a long run at which point it would loose power & eventually cut out. After some investigation he found that the new exhaust was less effective at taking away the heat from the engine & the piston was seized in the block.

[dandywarhol]

123 deg. C is dangerously close is to blowing off the 1.1 bar pressure valve in the cap - you don't wanna be doing that - especially if your radiator cap is also a pressure one

[teenmal]

£1 per resistor? I remember when they were 3p each from Maplins .

I'm led to understand that the exhaust manifold & pipe are a key part in the cooling system by acting as a heatsink to take the hot gases away effectively. So, the fact that side of the engine is hot is probably a good thing. A friend of mine has Vespa scooter to which he fitted a swanky stainless steel exhaust. It would run great until he went for a long run at which point it would loose power & eventually cut out. After some investigation he found that the new exhaust was less effective at taking away the heat from the engine & the piston was seized in the block.

Hi Simon the cost of the resistors will be less than £1.00 for 2.

[haydn callow]

But aren't these observations all a bit unscientific. How do we know what temperature at various points in the engine/exhaust system equates to the engine core 'going critical'? Taking it to the extreme, if you attached the temp. sensor to the exhaust manifold, you'd wonder from the temp. readout why the oil was'nt boiling, never mind the coolant.

Or have I missed something (probably, knowing me ). But I must admit, trying to work out exactly what the Bongo temp. gauge (and other cars too no doubt) is there to do does remain bit of a mystery.

I think you are spot on Mike....when I had the sensor on the inlet side under a rocker cover bolt the gauge never went above 96C towing on a hot day. The big differance in the Metal Temp at various spots on the cylinder head must cause stresses and strains which over time could lead to weaknesses. I just pointed this out co's I was suprised at such a high temp at point subject to watercooling.

[not so old]

HiHaydn
That's very hot I had mine in that same place, and, like you never got more than upper 90's 110....other members have had the same readings there, but 128 is abnormal. I have had the Bongo towing a very over-laden van, plus the whole rear of the car behind the middle seats ( which were pretty well forward) laden almost to the top of the windows. I drove from the midlands, all the way to and from the Chunnel, through most of Europe and eventually into Greece via Italy, and into Bulgaria....The temp . gauge sat still, but I know the radiator must have been hot, as the Bongo was down to second gear and struggling through the hills and mountains, to the extent that I often had to stop for a couple of hours to cool the transmission, which cools through the bottom of the rad. The Bongo does not like long periods of towing (in excess of 4-5 hours)...most days, this extended my driving time to 12- 14 hours daily. Having given it this much of a test, I would concur......the standard gauge is just a decoration, and serves no function whatsoever, except as a talking point for us coolant-mad Bongoists, one of which I count myself , having TM2....low coolant , high coolant alarm, plus one of your heat sensors. I am also fitting a water temp. gauge in one of the coolant hoses soon.....just for interest!
Cheers
Helen

Hi Helen,
As you have probably observed, I am worried about the overheating issue and I tow a small caravan. We will be going Touring Scotland soon and I am getting worried about the long winding hills. Last week I had a problem at 110 deg after taking a short, but steep hill. At the bottom of this short hill the Temp was 88 and in the couple of minutes it took to climb ,it was 110 and still going up while we sat at the traffic lights which were at the top of the hill. If you have found the Bongo is not happy towing more than 4-5 hrs, we should have to let the caravan or Bongo go, but many people tow with their bongos, I am somewhat concerned ,even though people tell me it's OK
When the alarm went off at 105 , the car was on a flat road, but the sun was quite hot in the cab and shining on the bonnet. I wondered if the combined heat of the sun on the top of the sensor added to the recorded heat of the engine where the sensor is in situ. What do you think. It's all double dutch to me, what the guys are talking about, however through reading this I have learnt that normal driving without towing temp should be between 70- 105 normal. Just wondered what you thought. If you can understand what I'm rambling on about that is

[haydn callow]

Not so old....if your sensor is on the exaust side in one of the threaded holes I would not worry....If it rightens you put the sensor under a inlet side rocker cover bolt....The temp on there will be 20 degrees lower but it will be just the same as it has ALWAYS been on the exaust.....Don't worry.

[not so old]

Thanks Haydn The mechanic put the sensor as instructed on the instruction sheet, so it must be on the proper side. We tow an Eriba too and it was the towing for a long distance that was concerning me. Thank you for your reassurance.

Anna

[dandywarhol]

I suppose this thread goes to show why Mazda damped their guage................

[g8dhe]

I guess the mod teenmal is referring to is based on these from the Miata ? The original site only partly exists now but the WayBackMachine helps

[The Great Pretender]

I think my viewpoint on trying to read coolant temp are well known so I won't repeat myself.
I have a thermistor in the in the coolant inside the outlet hose from the head feeding a digital gauge that reads down to a tenth of a deg c.
My readings may help you guys understand your readings better.
The standard gauge dosn't start moving untill near 70c, if 45c on yours the head is playing catch up. The needle reaches 11 o clock around 75c and thats it as my coolant has never gone over 92c.
The high readings you get could be picking up heat soak from exhaust gas.

Resistors in maplins 15p each

[teenmal]

I think my viewpoint on trying to read coolant temp are well known so I won't repeat myself.
I have a thermistor in the in the coolant inside the outlet hose from the head feeding a digital gauge that reads down to a tenth of a deg c.
My readings may help you guys understand your readings better.
The standard gauge dosn't start moving untill near 70c, if 45c on yours the head is playing catch up. The needle reaches 11 o clock around 75c and thats it as my coolant has never gone over 92c.
The high readings you get could be picking up heat soak from exhaust gas.

Resistors in maplins 15p each

Hi I will been looking for resistors in maplins,can you give me the part No.

[The Great Pretender]

Resistors in maplins 15p each [/quote]

Hi I will been looking for resistors in maplins,can you give me the part No.[/quote]

Yep, if you give me the value of the resistors you want.

[teenmal]

Resistors in maplins 15p each

Hi I will been looking for resistors in maplins,can you give me the part No.[/quote]

Yep, if you give me the value of the resistors you want. [/quote]

ha ha