temperature difference - steel pipework to adjacecent rubber

[missfixit70]

I think the metal stub will always read HOTTER than actual coolant tempreture once up to tempreture. After all the coolant is exaxctly that...Coolant ..and it's job is to cool down the metal bits.....When my coolant is at 65C the metal bits are 75C

Good point
Got some new numbers from Jaylee today (head vs heater supply). Sent graph to Jamie to get his opinion. Waiting for his response before posting. Results are not exactly what I expected and need some explanation attaching to the graph. Got me scratching my head

That's ok in theory, but the temp at the rad inlet (stationary, ie bleeding & monitoring temps) reads the same as at the top stub metal (+/_ a degree or 2) when the engine is up to temp, the only way this can happen is if the "coolant" ("equilibriant" would be a much better term ) is carrying the heat around (it can't gain 10 degrees from nowhere can it?), so I don't really agree with that. Just my opinion from what I've observed & logic as I see it, happy to be proved wrong

[widdowson2008]

OK - this is the last set of figures from Jamie for you to pick the bones out.
Red (solid line) is the top hose stub
Blue (solid line) is the heater supply hose
Red dotted line is the stat fully closed
Blue dotted is the stat fully open
The peaks are where the van was stopped in a layby with the engine running.

comments welcomed.

[Northern Bongolow]

I've put a sensor in the engine top hose. My water temp will really struggle to get to 82c (stat opening) during normal running. During normal travel it generally hovers around the 72-75 range

ive got one on the metal stub outlet (digital) and a mechanical one in the heater circuit, and i get figures the same as above, and my stat rarely opens unless hammered or ticking over.
i would be interested to know what stat and engine oil are fitted to jamies, as both these will have an effect on the figures quoted.
i know the actual figures are not the topic, but the difference between the positions being monitored. but the stat/oil could affect the difference in the two temps registered/seen.

sorry kirsty but i have to disagree with your remarks about the gauges kincaid has fitted reading down (but i would wouldnt i). the system in my opinion has to be taken as a whole.
some bongo's do run hotter or cooler than others for the reasons we all know, which may make them more likely to problems down the line,others sail on for ever, what is more important really is what is normal for your motor, and if its controlling the heat within its own system. there has always got to be differences between one and another.

[Northern Bongolow]

OK - this is the last set of figures from Jamie for you to pick the bones out.
Red (solid line) is the top hose stub
Blue (solid line) is the heater supply hose
Red dotted line is the stat fully closed
Blue dotted is the stat fully open
The peaks are where the van was stopped in a layby with the engine running.

comments welcomed.

interesting to see the figures shown steve seem to back up the theory about the primary circuit(heater circuit) is the circuit that controls the stat operation.
running from the start(ambient) to iddle, the top hose out raises first, then the heater circuit .then as temps equalize on tickover its the heater circuit that rises via the expansion tank link and takes control of the whole system by acting on the stat, then the whole system is lowered.
this backs up the importance of good flow around this primary heater circuit and heater matrix's and the fitting of a good quality stat.

[missfixit70]

sorry kirsty but i have to disagree with your remarks about the gauges kincaid has fitted reading down (but i would wouldnt i). the system in my opinion has to be taken as a whole.
some bongo's do run hotter or cooler than others for the reasons we all know, which may make them more likely to problems down the line,others sail on for ever, what is more important really is what is normal for your motor, and if its controlling the heat within its own system. there has always got to be differences between one and another.

I fully agree, the system has to be taken as a whole, hence my comments above, if the rad inlet is running at mid 80's, then the coolant must be transferring that heat, ie the outlet from the engine must be the same, it can't acquire 10 degrees of heat from nowhere - I was looking at the system as a whole rather than one point in isolation to prove my point & I've checked those figures to be similar on several bongos.
Mine has a Mazda stat & 5w 30 oil, same as yours I believe (& don't forget, new head, all new pipes & hoses, new waterpump, new stat & new rad, only diffrence is no rear heater matrix which shouldn't make any difference as some came out of the factory the same)