ANOTHER OVERHEATING BONGO, HOPEFULLY SORTED

[haydn callow]

Misunderstanding: Edited.

[haydn callow]

The top hose is always hot co's the bypass uses it

[Jamesnjane]

Haydn you know what your talking about can you just run this by me its confusing me, the flow goes from the bypass throuh the top of the rad then through top hose back to engine, so if the stat opens hot water would flow down the botom hose to the rad but wouldnt that make the bottom hose hot not warm???? then the top hose would be cooler cause it got cooled through the rad?? surley the flow of water would not change direction??? maybe iv missed something but its boggling my mind.

thanks

[Vanmanerik]

Haydn, I just came across your previous explanation.

So not only does the coolant run the 'wrong way' around the system but the bongo engine loses about 60% of it's heat in the exaust, under normal driving conditions the remainder of the heat is dissapated via the two smaller bypass pipes that go from the cyl head to the expansion tank and back to just above the stat. Only under extream conditions does the stat open and allow hot coolant down through the bottom hose into the bottom of the rad where it cools and returns via the top hose to the cyl head.

So we have a motor that the thermostat only opens under extreme conditions, God help us all - I'm off to the pub - a few pints might put his last one in perspective. Now let me see.... the engine is screaming hot but I must not worry, the engine is screaming hot but I must not worry, the engine is screaming hot but I must not worry. I just wish I wasn't sitting right next to the engine.

Jamesandjane, if you wanted you could tell us which way the water flows. Drain your header tank, save the coolant to refill it, and then take the cap of the rad ONLY WHEN THE ENGINE IS COLD start your engine and you should see some movement of the coolant in the radiator as you have a 'holey' thermostat, is it going left to right or right to left as you face the radiator? If its right to left then the flow is from the top of the engine, right to left it is from the bottom of the engine (thermostat).

[Peg leg Pete]

Still think the thermostat and radiator do more work than these theories would have us believe, or else Mazda would fit a tiny less expensive one

[Jamesnjane]

i could give it try, only probs would be the vibrating making it unreadable but its worth a shot, do you see where im coming from about the bottom hose being warm surley if the stat opens it should be hot water going to the rad to be cooled??

[Peg leg Pete]

So who can come up with a flow direction diagram for the bongo??

[haydn callow]

vanmanerik.. Nearly right but the bypass coolant returns from the expansion tank via the larger of the two pipes to the top of the rad (not directly to the cyl head) and from the rad via the top main hose to the cly head. (I thinK!!!)

[Jamesnjane]

if its as haydn says it is, then the flow goes through the top hose back to engine, if the stat opens why is the bottom hose warm????? that would mean the flow of water changes direction??????? in my eyes if the stat opens the water would be red hot needing to be cooled, not warm.

do people understand what im saying or am i making a t*t of myself

[Peg leg Pete]

James you make sense with what you are saying

[haydn callow]

vanmanerik .. if you notice the diagram of the MGF circuit also flows hot to the bottom!!

[haydn callow]

jamesnjane. IF?? the stat opens the bottom hose does indeed get hot. It is normally cool or warm at best just by heat soaking through over a period of time

[Peg leg Pete]

[Jamesnjane]

but alot of people say, even the manual that the bottom hose warming up shows the stat opening??? clearly not so

[haydn callow]

absolutly is so! not only will it get warm when it opens it will get bloody hot. I only say it gets a little warm to the touch co's a little warmth soaks through.