Mazda temperature gauge

[jaylee]

Also bring into the Mason mod factor that the more electrical load (headlights/ heater fan on full) the gauge can go a little higher!!

Mazda temperature gauge - Mason modified


Mine has for four years... & still freaks Bellhill! I like this though Steve, calming to look at... Unlike my own gauge.

Hi Jaylee
So.....are you saying that the Mason modified gauge shows not only a temperature change in the head, but will vary according to the electrical load of headlights/ heater fan on full, etc?
Does this happen on all Mason modified gauges?

I believe so, yes. But, depending on other electrical mods... I ended up putting a fat load on when run up to temp & setting above the peep... Bongo been fine since!

See this thread from last October here... http://www.igmaynard.co.uk/bongo/forum/ ... +detective

[widdowson2008]

Hi Jaylee
Read through your link. Didn't realise that electrical loads could affect the gauge.
If this is the NORM, then the Mazda gauge is far worse than I thought, and it's bloody frightening .

I know I will get crucified for this (but I am now 100% convinced). If there is anyone out there considering modifying the standard Mazda gauge, IN ANY WAY, in order to get a true idea of what your cooling system is doing, FORGET IT and fit a digital readout.
The Mazda gauge is a fairy story. If you modify it IN ANY WAY, all you will finish up with is an embelished fairy story. It will tell you NOTHING!!!!!!!!!!!

Before you start firing bullets, please bear in mind that I am a bloke who deals in facts, backed up by numbers.

[jaylee]

Hi Jaylee
Read through your link. Didn't realise that electrical loads could affect the gauge.
If this is the NORM, then the Mazda gauge is far worse than I thought, and it's bloody frightening .

I know I will get crucified for this (but I am now 100% convinced). If there is anyone out there considering modifying the standard Mazda gauge, IN ANY WAY, in order to get a true idea of what your cooling system is doing, FORGET IT and fit a digital readout.
The Mazda gauge is a fairy story. If you modify it IN ANY WAY, all you will finish up with is an embelished fairy story. It will tell you NOTHING!!!!!!!!!!!

Before you start firing bullets, please bear in mind that I am a bloke who deals in facts, backed up by numbers.

Hi Steve,
Northern Bongalow (Ady) i understand has experienced similar...

I certainly have no "loaded gun" on the temp gauge mod possible issue & would agree with the digital readout idea...
But i will point out in fairness that the mason did stop & save me when my top hose went 3 years ago!

Your work regarding the cooling system seems to cover all basses.. I'm sorry if my initial comment (which was merely a joke observation on the Mason quirk.) has provoked another query on your part.

My occasional input to your threads are by no means a besmirchment on your relentless hard work on the subject!!

it would be interesting if any other Mason modded owners have had the same...?

I would just like to add i don't have any sub bass, or soup'd up amplification installed to cause such a drain... Just a standard 4x50 watt set up from the head unit!

[widdowson2008]

Hi Jaylee
I've had a couple of responses suggesting that your experience is not isolated. I agree with you, a few more +ve or -ve would be welcome.
Gotta stress - I'm not trying to rubish any of the gauge mods. Anything that helps alerting the driver to a possible overheat has GOT to be the way to go. All I'm trying to get over is that in my opinion, fudging an already fudged gauge is not the way to do it. All you will get is a fudged idea. That's only my opinion, being a numbers man. Can't beat numbers.

I will be seeing Ady soon, so I'll get his input/opinion.

[lazyb5]

Hi all,
I modded my gauge almost immediately with a mason. After i fitted it i noticed it went towards the 2 oclock when warmed up. When i was booting it i noticed the gauge begin to climb so backed off and the gauge went back to the 2oclock. Decided i didnt like it at the 2 oclock position so i flushed the system replaced the thermostat and bled the system according to the videos and kept at it until the thermostat opened and the bottom hose was hot. The temp gauge now stays at 12 oclock and only sometimes moves a little past when going hard. Never noticed any fluctuations even when electrical devices are on but i have a leisure battery and the radio blinds and sunroof come off this.

[mister munkey]

The first year of having mine was running with a standard gauge where it sat around the 12 o'clock position all the time. Except for when it overheated & cracked the head, which of course alerted me too late.

After fitting a Mason, it tended to settle around the one o'clock position with noticeable increases up past 2 o'clock when lugging up long hills. It was like this for two years until the radiator was replaced.

Since then, its changed its profile considerably & now sits around 12 pretty much all the time, hardly moving up even when booting it up Windy Hill on the M62 fully loaded & pulling a trailer on a hot day (remember them?). I used to have it set to Chirp at 5, now its at about 3.5 and its not gone off once in the last 6 months.

Point being the improved coolant flow of a new Rad has made the same alarm on the same engine perform in a different way.

One mans Mason may behave the same as another mans Haydn, depending on the state of the plumbing.

[g8dhe]

All gauges will to some extent have a sensitivity to the supply rail, but I can't say that I have noticed that the temp. gauge is particularly sensitive in the Bongo. The way the circuit is arranged is known as bridge circuit and these are the least sensitive of all, carrying out the mods does not affect this basic type of circuit arrangement so I would be a little surprised to find that the gauge is badly affected by the battery voltage at least not until the battery is very badly discharged.

[widdowson2008]

lazyb5 and mister munkey appear to have had similar experiences. Is this perhaps the NORM, and Jaylee has a rogue in there somewhere?

Then, along comes Geoff with his electrical knowhow and throws a 'bridge circuit' into the mix (not a clue ), stating that this is the least sensitive.
Geoff - When you say '..........surprised to find that the gauge is badly affected by the battery voltage ', is this related to whatever electrical circuits are being used (as in Jaylees example)?

[g8dhe]

What does the Mason modification consist of ?
The Haydn / Factsheet modification uses the same balanced bridge circuit which only changes the sensitivity of the existing circuit to temperature changes, but won't affect its sensitivity to battery voltage changes. I've not noticed any change in my temp. gauge despite the battery voltage ranging between 11 to 14 volts. Outside this range and other things will be having a problem in the vehicle and it uses the Haydn / Factsheet method!
If anybody wants a more detailed explanation as to why it shouldn't change with the supply voltage then I'll happily provide it but will need a little warning in order to keep the words to one syllable and a few diagrams

Edit: OK found Mason factsheet, but not enough info. to be certain how it works, but as it doesn't replace the Zener diode then it must overcome the "dead range" more by brute force than anything else, so it MIGHT/MIGHT NOT be more sensitive to battery voltage changes.

[Northern Bongolow]

i think the mods on there own are all great,and all do a valuable job. i use several of these on my motors.
in my experience,the variable factor is the base motor.
ive had particular problems with my motor and geting it to read anything sensible, ive done bench tests with different senders,diff mods,and several gauges.
the conclusion i came to was that the inaccurate results always stemmed back to imput voltage.
where in the bongo is the voltage stabilizer for the clocks/gauges, does it have one, or is it as i suspect this bridge circuit that is supposed to do the (smoothing). can this go wonky??.
i know of 2 others that are having trouble with falsely high readings (showing a slight reading when cold)

[g8dhe]

where in the bongo is the voltage stabilizer for the clocks/gauges, does it have one, or is it as i suspect this bridge circuit that is supposed to do the (smoothing). can this go wonky??.

That's right it is the bridge circuit, that balances out supply voltage changes, and hence why a voltage stabiliser / regulator isn't needed.
Can it go wrong ? Not easily without causing the meter to change position significantly, the bridge circuit has two halves, one half is created by the two coils that cause the needle to move, if either of the coils changes in any way then the needle would move significantly, the only way the needle wouldn't move is if both coils changed together, which is VERY unlikely!

[Northern Bongolow]

thanks geoff ,understand now .
so what could affect the imput voltage to such an extent that it affects the observed reading.
as i said above ive seen 2 that are registering a small reading on the gauge when the ignition is switched on when cold.
not mine by the way ive sorted mine now.

[g8dhe]

ive seen 2 that are registering a small reading on the gauge when the ignition is switched on when cold..

OK switching ON, and seeing a small change is expected, that is going from 0 volts to probably 12volts and is outside the normal range (11-14v).
If you then start the engine, the voltage will rise from 11 - 12 volts up to about 14 volts, a very small change (less than a needle's width I would expect but not checked) could be expected, if its significantly more than that, then something unexpected is happening. However the needle doesn't normally move much until the temperature has risen to around 70°-75° when it should be passing on to the lower end of the scale.

Is that what your seeing ?

[Northern Bongolow]

its the significantly more we are talking geoff,and its stays there until the raising temps that are normally registered overtake this initial reading.

[g8dhe]

OK so its between Ignition On and when the alternator starts charging, how much movement do you see, is it actually on the Temp scale at that point or still below it ?

I take it that the gauges are standard Bongo ones and not an instrument panel from another similar vehicle (that's not to say that they are different but trying to think what else might have an effect!).