Mazda thermostat - A few observations

[Northern Bongolow]

hi steve,i think you know my methods on this dont you,short answer is yes.

[widdowson2008]

hi steve,i think you know my methods on this dont you,short answer is yes.

Old school - can't beat 'em

[missfixit70]

And when bleeding after a coolant refill? 4 degrees sounds a lot, especially at the top end.
Perhaps if the stat is woken up before fitting, the bleeding process may be easier? Not a statement, more a question.
Has anyone pre heated their stat in this way before fitting?

How would you preheat it to this level Steve?
By ensuring the bottom hose gets HOT, IMO that means the stat has opened FULLY & has effectively proved this full operation of the stat & "primed" it (but what about 2 weeks later when it's been sat on the driveway doing nowt?)
If the bottom hose does not get hot while bleeding, as the cooling effect of the rad is minimal while stationary (15 degrees ish on mine) if the bottom hose is only getting warm, the outlet form the engine is only a bit warmer which IMO means the stat is not shutting in the top recirc port (Which when shut forces more flow out of the head rather than recircing & allows more flow in through the bottom of the stat).

[widdowson2008]

And when bleeding after a coolant refill? 4 degrees sounds a lot, especially at the top end.
Perhaps if the stat is woken up before fitting, the bleeding process may be easier? Not a statement, more a question.
Has anyone pre heated their stat in this way before fitting?

How would you preheat it to this level Steve?
By ensuring the bottom hose gets HOT, IMO that means the stat has opened FULLY & has effectively proved this full operation of the stat & "primed" it (but what about 2 weeks later when it's been sat on the driveway doing nowt?)
If the bottom hose does not get hot while bleeding, as the cooling effect of the rad is minimal while stationary (15 degrees ish on mine) if the bottom hose is only getting warm, the outlet form the engine is only a bit warmer which IMO means the stat is not shutting in the top recirc port (Which when shut forces more flow out of the head rather than recircing & allows more flow in through the bottom of the stat).

Sorry Kirsty - I think you may have misundertood (or perhaps I didn't put it very well)
I wasn't suggesting anything else but 'stick it in a pan'. Once it has opened, on subsequent tests the stat I tested opened earlier (by 4 degrees). All I was suggesting was that perhaps a brand new stat needs 'waking up'. Once aroused, it seems to perform differently (Quicker response). It was just an observation - not meant to cause mass discussion. And I say again, these results were from ONE Mazda stat. It may have been a fluke. ie, another Mazda stat may not behave the same.
And as for '2 weeks later', I can't say because I haven't tried it. And never will now because that particular stat, along with new hoses, gauges, temperature gauges(5), turbo pressure gauge, synchronisation of said gauges, and a host of other bells and whistles is winging its way to foreign lands to be fitted into a Bongo for road tests. (Just checked Post office tracking and it's at the airport). Looking forward to some data coming back so that we can really establish (from the logged data) precisely what's happening around the cooling system.

Pity we can't replicate something similar on your Bongo to get a second view.

[missfixit70]

You're right, I misinterpreted the question, but as 3 of us had agreed so far that testing like this before fitting (based in mine & Ady's case of doing just that ) maybe a slightly redundant question

Saying that, the Blueprint one I tested & fitted, opened quicker than the one that was taken out on the first go at boiling it.

As for fitting a replicated test set up, it's down to finance, time & energy constraints I'm afraid. Struggling to get the rear conversion sorted & keep getting sidetracked by other things.
I'll be fitting at least one more temp gauge though (on the top hose outlet) & will try & calibrate it's accuracy before fitting. Next time I do a stat change I'll fit a genuine Mazda one, but I'm happy with how mine's runnig ATM, just want to see how how it performs on a longer run with the rear gubbins removed.

[widdowson2008]

...............just want to see how how it performs on a longer run with the rear gubbins removed.

Yes - the results will be interesting and well worth a read. Looking forward to them.
Don't forget to log the data

[missfixit70]

...............just want to see how how it performs on a longer run with the rear gubbins removed.

Yes - the results will be interesting and well worth a read. Looking forward to them.
Don't forget to log the data

Hmm, tend to be a bit too busy driving to be able to log too much but I'll remember what I can, doubt it'll be too much different.

[widdowson2008]

...............just want to see how how it performs on a longer run with the rear gubbins removed.

Yes - the results will be interesting and well worth a read. Looking forward to them.
Don't forget to log the data

Hmm, tend to be a bit too busy driving to be able to log too much but I'll remember what I can, doubt it'll be too much different.

NUMBERS NUMBERS NUMBERS

[widdowson2008]

I was asked to test a thermostat which had been in a in service in a Bongo for 4 years.
This is what I found.
Thermostat - genuine Mazda - 4 years old. Mileage covered not specified.
Stat tested 5 times. Following resuts were identical in all tests. (pretty consistent)
Start to open temp. 85/86 deg.C (spec states between 82 and 84)
Fully open temp. 98 deg.C (spec states 96)

Conclusion
Whilst this stat responded quickly to temperature changes, both the 'start to open' and the 'fully open' temperatures were 2 deg.C above specification, ie a bit sluggish but not much. I would expect this sort of behaviour if the stat had lost a small amount of wax.
I think I would not be too unhappy if mine were the same. However, the decision to change it was the right one in my opinion.

Any comments? Have I missed summat?

[widdowson2008]

Forgot to say that the 4 year old stat was in VERY clean condition when removed, suggesting that the owner is taking care of his system.

[Northern Bongolow]

it would suggest to me steve that even with a gen stat fitted,that things must be maintained to operate correctly,even if things are going well,with no symptoms,change your stat and other things at regular intervals.
the person who said if it aint broke dont fix it didnt have a bongo as his first motor.
good work steve.

[Alacrity]

Just to say, I fitted a new Bluepoint stat to my Bongo about 14 months ago, no problem UNTIL I fitted a Mason - then I was concerned as to how high the gauge ran, considerably higher than folk on here said they run with a Mason. It seemed OK though & I checked the top hose after a run & it wasn't too hot (can't remember the exact figure now) so I didn't worry to much although it did pester me. It wasn't unusual for the alarm to chirp when going up hill & the temp would climb very high. A couple of weeks ago I fitted a Mazda stat & the difference is immediately apparent, the temp mow runs just past past the upright which I gather is normal, some 3/16 lower than it was, & as yet the temp has never got anything like as high as before even when towing a boat up a long steep hill last weekend. The gauge hardly moved & the alarm remained silent all day. I'm much happier now & don't spend all my time watching the gauge instead of the road!

One thing of note that goes along with Steve's findings, the very first road test after fitting the new stat the temp did rise quite high & the alarm chirped for a second or so, it then immediately dropped back & has remained steady ever since. It seems the stat needed 'waking up' as has already been mentioned.

[mikexgough]

I am on the 12'oclock mid point via Mason using a Tama Industries 'stat.... (they make 'em for Mazda)... Got a Stahler and an NT cooling to test and one tester lined up...

Doing Brake pads just now....changed for O.E supplier Allied Nippon's, replacing the NA Sumitumo ones, but that's another story..... Allied Nippon supply Mazda,Honda,Toyota,Brembo.....

[widdowson2008]

Look forward to Mikes test results of the Stahler and an NT cooling.

After replacing a core plug (Mazda) today, together with a new thermostat (Mazda) and a new fan switch (Mazda) (well...if truth be known, Ady did all the work), I have a few observations to share.

1 - The stat removed was a Blueprint . It was working fine and in a very clean condition (as was the surrounding pipework), even though it had been in since I bought the Bongo two and a half years ago, and probably at least one year older than that (previous owner was a woman and I don't suppose she changed it).......... However, I intend to pan test it to see exactly when the start and maximum temperatures occur. Perhaps the Blueprint ones are not that bad after all

2 - Coming home, on the 30 mile up/down country section (very hilly), a bit of stop/start village stuff, and the 40 mile motorway section at a nominal speed of 60mph, I monitored the TM-2 very closely and made some observations which may change my view of the cooling operation slightly. Need a little time for the new stat to settle down before I publish results, but VERY interesting indeed.

3 - Also need to get to bed - (I'm nackered after today) - but I'm sure the grey matter will start to churn once I get in bed.

[Alacrity]

Perhaps the Blueprint ones are not that bad after all

Well I wouldn't use one after my experience with Bluepoint , the difference with a Mazda one is huge!