Cold Bottom Hose

[HeskinBongo]

Have recently refilled with antifreeze but think i have a problem, Yes seen the 3 youtube videos, but still have cold rad lower hose even after 6 mile drive in 5 degree outside temp, internal heaters working great and temperature gauge showing normal.

Am i paranoid when the bottom hose remains cold ?

[Northern Bongolow]

hi in my opinion-----no your not. but if the bottom hose doesnt get hot how do you know that everything is fine.im not saying either that anything is wrong,but just asking what other method peeps use to tell if all is well,other than the its to late method. if using the video method,the bottom hose must get hot,(stat open)not just warm,for the bleed to be completed.
your problem, in my opinoin(again) shows the reason for highlighting this key point.
if you bleed via the other methods,how do you know when it is fully bled. you dont,has to be the answer.you must rely on the bongo doing it for you.this it may do,in time,but when, after 10 miles? 30 miles? tomorrow, or indeed after the head or gasket has been weakened,? and all this normal bleeding relys on all the system being in A1 condition,which it may or may not be,again how do you know?
if you bleed via the video method,you will clearly see the key moments, that in my opinion(again)should be observed,and at which points,and when.
there are several other methods of bleeding that are approved, and used by others with success,what you must find is a method that you can make work for you,

the point i would make is that i make a daily trip of 10 miles each way to work,it involves motorway,and slower driving,and very rarely does my stat open,this is measured with several temp monitoring devices fitted at key points on my motor.the very action of the bongo moving through the air on an efficient cooling system is often enough to delay this from happening for quite some time.
is your temp gauge modified,or is it standard. does it normally sit at 11 oclock. if its standard it wont tell you there is anything wrong until its happened,because it is damped.

[HeskinBongo]

Thanks for your reply ADY

Its enlightening to read that on your 10 mile commute that your stat dose'nt open, this is most likely my situation, also verified by excellent heating inside the bongo.
As for the temp gauge i assume it is as std as yes it does sit at 11.00 o'clock posn normally

I feel more comfortable about the bottom hose remaining cold now, Thankyou

Shall be keeping a close eye on levels etc

[mikeonb4c]

Haven't read through NB's post but my temp gauge starts to move of from the Cold stop after about 5 mins driving. I take this as a clear indication that the stat has opened and circulating/warming coolant is starting to flow past the temp sensor. Before I put a new thermostat in, it used to take twice as long for this to happen (which is why I feel confident in linking this event to the stat opening).

The temp gauge then moves steadily to the 11.00 oclock position and stays there.

Don't know if any of this helps but if yours is behaving the same, then it would seem odd to me that the bottom hose is still not warming.

Good luck - keep the old girl under close observation I reckon.

[helen&tony]

Hi
Mike
The sensor for the water gauge measures the water jacket, and the stat has no bearing on it whatsoever...On the Standard gauge it will tell you that the water is up to temperature, and should it rise, then you stop, and check...It does a perfectly adequate job....Ignoring the gauge is what causes the problem!
For a constant picture of rise and fall in temperature, a TM2 is the jobbie!...or one of Haydn's gauges!
Cheers
Helen

[westonwarrior]

10 min is just not long enough to get it hot even though the temp guage says so

With a tm2 alarm I used to see that the guage showed normal running temp when the tm2 showed about 55 degrees but the temp kept raising to the normal running temp of about 90 on the tm2 and that took ages sometimes 30 min or more.
and if stationary can take longer as using less revs.

the stat may not open at all in the currant weather unless the engin is realy pushed as the wind factor is doing the job its supposed to and cooling the engin.

[mikeonb4c]

Hi Helen

I wrote a long reply but failed to noticed someone posted in between (I'm full of cold/flu) so lost it

I'm familiar with the cooling system explanations on here but, to sum it up, glider pilots say:

Study the weather forecast. But don't ignore the sky above you and, if there are good contra-indicators, set your task based on what you observe and not on what the forecaster says.

Something makes the gauge move off the C stop. Whatever that something is, the time for it to happen halved the moment I fitted a new stat. That's too much of a coincidence and I shall use this indicator to decide when my stat needs replacing.

My hunches have generally served me well in the past BUT I don't claim to be an expert so others will have to make their own decision.

PS - I thought TM2 WAS one of the gauges Haydn sells?

PPS - its at times like these that I wish that, instead of justing celebrating the Bongo in their company magazine, Mazda could actually do something useful and give us chapter and verse on all this.

[helen&tony]

Hi
There is no hard and fast distance or time for the standard gauge to get up to normal...It depends on the ambient temperature, but in good weather , 3 or 4 kilometers gets it to normal, with the TM2 (where i have mine bolted) reading mid to upper 40s, then rising to it's own normal running reading..If the time or distance in getting up to normal temperature seems longer, then, yes, the stat may be open a bit, showing a lazy or malfunctioning stat, but normal summer temperatures sees the gauge showing normal after 3-4 Km. Winter is another story...it takes a little longer.
Yes...Mike, Haydn does sell TM2s...I forgot ...I bought mine ages ago before he was selling them
Cheers
Helen

[haydn callow]

Haven't read through NB's post but my temp gauge starts to move of from the Cold stop after about 5 mins driving. I take this as a clear indication that the stat has opened and circulating/warming coolant is starting to flow past the temp sensor. Before I put a new thermostat in, it used to take twice as long for this to happen (which is why I feel confident in linking this event to the stat opening).

The temp gauge then moves steadily to the 11.00 oclock position and stays there.

Don't know if any of this helps but if yours is behaving the same, then it would seem odd to me that the bottom hose is still not warming.

Good luck - keep the old girl under close observation I reckon.

What happens is !!!! The standard Bongo temp gauge is activated by a sensor which is located in the cylinder head......When the coolant in the cylinder head reaches 25C the gauge starts to move....when the coolant in the cylinder reaches 45C the gauge will be at it's "normal" 11 o'clock position.......it will then sit at that position untill the coolant in the cylinder head reaches "approx" 110C.....and you are on the cusp of a overheating event.....

The Thermostat on the other hand only starts to open at 82C.......this is not often acheived under normal driving conditions and in cold conditions...the top hose/top rad tank/expansion tank/heating system is capable of providing enough cooling to prevent the Stat from opening...when you slow down or stop the temp will rise and the coolant that is circulating will reach 82C and cause the Stat to start to open....this allows the Rad to come into action.....
The best way to get the bottom hose hot (proving the Stat is working) is to go for a run then let the Bongo tick over for a few mins. This should force the Stat open

[haydn callow]

Hi
Mike
The sensor for the water gauge measures the water jacket, and the stat has no bearing on it whatsoever...On the Standard gauge it will tell you that the water is up to temperature, and should it rise, then you stop, and check...It does a perfectly adequate job....Ignoring the gauge is what causes the problem!
For a constant picture of rise and fall in temperature, a TM2 is the jobbie!...or one of Haydn's gauges!
Cheers
Helen

SPOT ON

[helen&tony]

HI Haydn
Actually, I should have mentioned, as I have all manner of gauges, that I have a couple of yours, and I reckon the CUBE series is good value for money...2 temperature sensors and a volt meter....The volt meter is essential if you are using auxiliary gauges, as fluctuating electrics can play havoc with your readings....As you may remember, I have an -alert AND a Cube from you...and the cube is best value!...
Regarding the voltage, I had a BMW classic 2002 some while ago, and I had the temperature readings going wild... checked everything out, and presumed the rad was a bit iffy...I had used a leak stopper, which worked well so I presumed it was the rad...I replaced that, and STILL had problems...so I went round to my Dad's and we pulled the head off....and BMWs don't like head removal...darned thing wouldn't budge....SO, re-connected everything and fired it up without the head nuts.....THAT did the trick ...my Dad's friend used his JCB to pull the head off his BMW ....Anyway...head was perfect!!!...The trouble eventually turned out to be a tiny voltage stabiliser on the back of the instrument cluster....SO...moral of the tale:....electrics can lead you up the garden path sometimes.....anyhow, the 2002 got a good checkout and a clean bill of health!
Cheers
Helen

[haydn callow]

HI Haydn
Actually, I should have mentioned, as I have all manner of gauges, that I have a couple of yours, and I reckon the CUBE series is good value for money...2 temperature sensors and a volt meter....The volt meter is essential if you are using auxiliary gauges, as fluctuating electrics can play havoc with your readings....As you may remember, I have an -alert AND a Cube from you...and the cube is best value!...
Regarding the voltage, I had a BMW classic 2002 some while ago, and I had the temperature readings going wild... checked everything out, and presumed the rad was a bit iffy...I had used a leak stopper, which worked well so I presumed it was the rad...I replaced that, and STILL had problems...so I went round to my Dad's and we pulled the head off....and BMWs don't like head removal...darned thing wouldn't budge....SO, re-connected everything and fired it up without the head nuts.....THAT did the trick ...my Dad's friend used his JCB to pull the head off his BMW ....Anyway...head was perfect!!!...The trouble eventually turned out to be a tiny voltage stabiliser on the back of the instrument cluster....SO...moral of the tale:....electrics can lead you up the garden path sometimes.....anyhow, the 2002 got a good checkout and a clean bill of health!
Cheers
Helen

These are now discontinued due to the high costs in getting them....I have a few left if any members want one.......

[mikeonb4c]

Hi
Mike
The sensor for the water gauge measures the water jacket, and the stat has no bearing on it whatsoever...On the Standard gauge it will tell you that the water is up to temperature, and should it rise, then you stop, and check...It does a perfectly adequate job....Ignoring the gauge is what causes the problem!
For a constant picture of rise and fall in temperature, a TM2 is the jobbie!...or one of Haydn's gauges!
Cheers
Helen

SPOT ON

What I need is a reason why I observed what I observed. Then I might be persuaded to consider that what I observed has no connection with the thermostat opening. Just reiterating what I already know (becuase its been discussed on here countless times), or saying 'SPOT ON' (ouch my ears are ringing) doesn't change things. So let's have a sensible debate please. Meanwhile, maybe stasis, or stagnant, have a bearing here?

Incidentally, Helen has asserted that the standard gauge is perfectly adequate for warning of dangerous coolant temperature rise. Is that really so, as I thought the experts regarded it as a 'chocolate fireguard'

[haydn callow]

Hi
Mike
The sensor for the water gauge measures the water jacket, and the stat has no bearing on it whatsoever...On the Standard gauge it will tell you that the water is up to temperature, and should it rise, then you stop, and check...It does a perfectly adequate job....Ignoring the gauge is what causes the problem!
For a constant picture of rise and fall in temperature, a TM2 is the jobbie!...or one of Haydn's gauges!
Cheers
Helen

SPOT ON

What I need is a reason why I observed what I observed. Then I might be persuaded to consider that what I observed has no connection with the thermostat opening. Just reiterating what I already know (becuase its been discussed on here countless times), or saying 'SPOT ON' (ouch my ears are ringing) doesn't change things. So let's have a sensible debate please. Meanwhile, maybe stasis, or stagnant, have a bearing here?

Incidentally, Helen has asserted that the standard gauge is perfectly adequate for warning of dangerous coolant temperature rise. Is that really so, as I thought the experts regarded it as a 'chocolate fireguard'

Mike, ......I have explained above why there is no relationship between the Temp gauge moving from cold to normal and the actions of the Stat.....to prove this....if you accept that for the stat to be open the bottom hose must be "HOT" next time you go for a run in the Bongo (or warm it up on your drive).....wait untill the gauge moves then feel the bottom hose.....it will be COLD. (Stat closed)
I'm afraid thats how it works
What you observed...Well !! beyond me....

[haydn callow]

Have recently refilled with antifreeze but think i have a problem, Yes seen the 3 youtube videos, but still have cold rad lower hose even after 6 mile drive in 5 degree outside temp, internal heaters working great and temperature gauge showing normal.

Am i paranoid when the bottom hose remains cold ?

No ! perfectly normal.......The Stat does not start to open untill the coolant reaches 82C......the gauge reaches normal position at about 40/45C.