Cooling system diagram

[Grahame at work]

Hi all,

I disagree with the last few comments.

The coolant flow is OUT of the head and down the by-pass to the stat housing so the turbo flow can only go down (in the diagram) to the T in the heater flow.

Unless - the flow down the by-pass 'sucks' coolant through the small bore turbo pipe work What actually does the coolant do in the turbo system? - cool what?

I'm still working on my words for Steve.

(hope there's still room at the wall for me)

Regards Grahame

[missfixit70]

Hi all,

I disagree with the last few comments.

The coolant flow is OUT of the head and down the by-pass to the stat housing so the turbo flow can only go down (in the diagram) to the T in the heater flow.

Unless - the flow down the by-pass 'sucks' coolant through the small bore turbo pipe work What actually does the coolant do in the turbo system? - cool what?

I'm still working on my words for Steve.


(hope there's still room at the wall for me)

Regards Grahame

plenty of room

Good point on the "what's it actually cooling in the turbo" thought.

[dandywarhol]

it's keeping the oil supply to the turbo cooler IMO

[mikexgough]

Cooling the turbo oil supply down makes absolute sense........as of direction of flow..... I don't suppose its critical as long as it flows to cool the oil....... I have my blindfold at the ready....... what time is execution.....

Working on my words for Steve too...........

[dandywarhol]

Been talking a few readings with a laser spot digi thermometer this evening.

The coolant flow definitely goes from the "branch" pipe in the upper head DOWN to the turbo and returns into the thermostat housing upper part. The water pump then takes it back into the engine block and convection currents take it back up again to the "branch".

The coolant flow definitely goes into the heaters from the right side of the engine block and returns to the thermostat housing.

The coolant flow definitely goes out the head under the driver's seat, travels to the radiator upper tank and out to the expansion/auxilliary tank, then returns back to the bypass system in the thermostat upper housing.

When the metal pipe temperature in the upper "branch" is around 90 deg C, the lower part of the housing is still at 60. (and the radiator lower metal pipe is around 18/20)

While the system is warming up (idling for 5/7 minutes) the lower radiator pipe and the metal pipe running towards the 'stat housing lower part is still around 18/20 deg.C. Running at 2500 rpm for 5 minutes and watching the temp gauge rise to midway the radiator top pipes and tank were showing 82/84 deg and the lower radiator pipe began to heat up. I was dashing around like a blue arsed by this time - crawling below the van, checking in the engine bay, operating the throttle........................

This part is now the confusing bit - the lower radiator metal pipe was a good 12/15 deg COOLER at the radiator end than the thermostat lower housing end..........................which was 10 degrees cooler than the 'stat housing upper part. does this mean the direction of flow (once the 'stat opens) is FROM the 'stat to the RADIATOR ............or is it just heat transfer because the engine area is hotter than the radiator

[mikexgough]

Been talking a few readings with a laser spot digi thermometer this evening.

The coolant flow definitely goes from the "branch" pipe in the upper head DOWN to the turbo and returns into the thermostat housing upper part. The water pump then takes it back into the engine block and convection currents take it back up again to the "branch".

The coolant flow definitely goes into the heaters from the right side of the engine block and returns to the thermostat housing.

The coolant flow definitely goes out the head under the driver's seat, travels to the radiator upper tank and out to the expansion/auxilliary tank, then returns back to the bypass system in the thermostat upper housing.

When the metal pipe temperature in the upper "branch" is around 90 deg C, the lower part of the housing is still at 60. (and the radiator lower metal pipe is around 18/20)

While the system is warming up (idling for 5/7 minutes) the lower radiator pipe and the metal pipe running towards the 'stat housing lower part is still around 18/20 deg.C. Running at 2500 rpm for 5 minutes and watching the temp gauge rise to midway the radiator top pipes and tank were showing 82/84 deg and the lower radiator pipe began to heat up. I was dashing around like a blue arsed by this time - crawling below the van, checking in the engine bay, operating the throttle........................

This part is now the confusing bit - the lower radiator metal pipe was a good 12/15 deg COOLER at the radiator end than the thermostat lower housing end..........................which was 10 degrees cooler than the 'stat housing upper part. does this mean the direction of flow (once the 'stat opens) is FROM the 'stat to the RADIATOR ............or is it just heat transfer because the engine area is hotter than the radiator

Good work their Alan..... would have love to have seen the Blue arsed dance...

Seriously....regards the radiator paragraph....I would think your heat transfer theory would be right ........ T
he only thing that has always struck me is the length of pipework from the bottom hose to the 'stat, which could cause a fair temperature drop and that coolant should flow from the radiator.....Mine has always been luke warm at the bottom hose, which suggests that the radiator is doing it's job but it is a good deal cooler than other engines I have worked on...... I do think that the Bongo system handles the temperature change when coolant is added from the radiator than other engines with a similar type cooling system.......perhaps the other radiators (heater matrices) help keep the coolant at a more even temperature......... better start walking to the wall of shame....

[widdowson2008]

This is factual
I did the above themal imaging of my Bongo in August this year, using a Flir P60 thermal camera.
Images taken looking at top, offside corner of raidator from the front. (ie:inlet)
Li1 top = 70.8, bottom 58.7
Li2 left = 77.1, right 64.3
The horizontal line Li1 recorded a drop of 12.1 degrees over the length of say 125mm (70.8-58.7)
The vertical line Li2 recorded a drop of 12.8 degrees over the height of say 70mm (77.1-64.3)
End of factual stuff

Both these indicate differences of approx 12 degrees over a short distance (dont know what it was over the full rad width) suggesting that the rad/fans are doing their job efficiently.
Is Alans data saying something similar?

The quest for a diagram has developed into a study of the system - Not intentionally.
Information/text gathered so far suggests the following (to me)
1 - The top of the radiator is heated by the return flow from the engine
2 - The bottom of the radiator is heated (to a lesser degree) by the ATF heat exchanger in the bottom of the rad.
3 - The centre section of the radiator does very little and remains relatively cold under normal running conditions - until the stat opens. And even when the stat opens, it doesn't slam open, but just enough to allow a dribble into the main circuit.
Another suggestion made is that the 'cooling' system, rather than being used to lower the temperature of the engine, is actually designed to maintain the engine at an optimum temperature (which is quite high).

[dandywarhol]

This is factual
I did the above themal imaging of my Bongo in August this year, using a Flir P60 thermal camera.
Images taken looking at top, offside corner of raidator from the front. (ie:inlet)
Li1 top = 70.8, bottom 58.7
Li2 left = 77.1, right 64.3
The horizontal line Li1 recorded a drop of 12.1 degrees over the length of say 125mm (70.8-58.7)
The vertical line Li2 recorded a drop of 12.8 degrees over the height of say 70mm (77.1-64.3)
End of factual stuff

Both these indicate differences of approx 12 degrees over a short distance (dont know what it was over the full rad width) suggesting that the rad/fans are doing their job efficiently.
Is Alans data saying something similar?

The quest for a diagram has developed into a study of the system - Not intentionally.
Information/text gathered so far suggests the following (to me)
1 - The top of the radiator is heated by the return flow from the engine
2 - The bottom of the radiator is heated (to a lesser degree) by the ATF heat exchanger in the bottom of the rad.3 - The centre section of the radiator does very little and remains relatively cold under normal running conditions - until the stat opens. And even when the stat opens, it doesn't slam open, but just enough to allow a dribble into the main circuit.
Another suggestion made is that the 'cooling' system, rather than being used to lower the temperature of the engine, is actually designed to maintain the engine at an optimum temperature (which is quite high).

Clever that! keeps the autobox fluid cool in most conditions

Which is what a thermostat is really designed to do...........Jeebus, I'm starting to sound/look like TGP .

[widdowson2008]

Clever that! keeps the autobox fluid cool in most conditions

Which is what a thermostat is really designed to do...........Jeebus, I'm starting to sound/look like TGP .

Do I detect a tad of p*ss taking here?
If the answers no, then I apologise for perhaps misreading.
I'm still learning about this Bongo stuff. I'm no self proclaimed 'guru' - just trying to gather information and learn.

[dandywarhol]

No I wasn't taking the piss - a lot of automatic cars have the gearbox cooler in the bottom of the radiator but the bottom tank area is a lot warmer in a "conventional" system. The bongo system with the cold bottom tank will cool the autobox fluid more efficiently.

Anyway, back to the lower hose heat transfer question - I reckon it's still going to be from radiator to 'stat housing, even though the temperature comparisons say otherwise. The water pump will pull the colant through the open 'stat and into the block to convect again up to the head. So the direction flow is as we first thought - rad to 'stat IMO

[mikexgough]

Anyway, back to the lower hose heat transfer question - I reckon it's still going to be from radiator to 'stat housing, even though the temperature comparisons say otherwise. The water pump will pull the colant through the open 'stat and into the block to convect again up to the head. So the direction flow is as we first thought - rad to 'stat IMO

I stand in favour of that concept and thinking.......

[widdowson2008]

Mission complete.

For me, the mission to get a Cooling system diagram is as complete as I am ever going to get it.

Many thanks to all those who helped.

[haydn callow]

Well done indeed !!!!!!

[dandywarhol]

Mission complete.

For me, the mission to get a Cooling system diagram is as complete as I am aver going to get it.

Many thanks to all those who helped.

Excellent - always best to keep these things for yourself - are you going to sell the diagram in the club shop?

[widdowson2008]

Mission complete.

For me, the mission to get a Cooling system diagram is as complete as I am aver going to get it.

Many thanks to all those who helped.

Excellent - always best to keep these things for yourself - are you going to sell the diagram in the club shop?

Nope
Freebie. Anyone who wants it, send me a pm with email address. It will be constantly updated and improved so if you want the updates, just ask.