Coolant coming out of expansion tank overflow pipe

Technical questions and answers about the Mazda Bongo

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marmaduke

Re: Coolant coming out of expansion tank overflow pipe

Post by marmaduke » Sun Jan 08, 2012 5:39 pm

Thanks I will look around. Just checked the radiator cap and its a 1.1 bar so swapped them around. However now the van won't start! I did run it for a while yesterday so not sure why its like that today!

I am slowly giving up on it. The garage I took it to is a Bongo specialist and they did a pressure test which showed no leaks and they did a sniff test which was inconclusive.

At this stage of the game I am thinking of selling it on as I spent more than I should on it and can't afford to spend anymore on it.

Thanks for all your advice.
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stuc
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Re: Coolant coming out of expansion tank overflow pipe

Post by stuc » Sun Jan 08, 2012 9:14 pm

dave_aber wrote:The short answer is "it might be".


As a side-note, some replacement radiators DO have a vent pipe which would allow a pressure release cap to work and dump pressure - this outlet must be blocked off on a Bongo.
Why is this? Mine has a extra pipe and runs absolutely fine, surely if you have no faults this shouldnt cause a problem.
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Northern Bongolow
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Re: Coolant coming out of expansion tank overflow pipe

Post by Northern Bongolow » Sun Jan 08, 2012 9:29 pm

the warmed up well thrashed bongo when healthy runs at 10 --11 pounds in the cooling system.
the first stage fans come on at 12-13 pounds. the second stage (not measured but just above).
then if your cap is good that pops at 1.1 bar.
the point is there is very little leaway in the system for it to get overhot without it blowing the cap.
most of the caps i pressure test fail(they blow to soon).
all it would take is a lazy stat, or poor flow somewhere and you could be in trouble.
if mine was to get hot i would want it to blow the factory built saftey valve, the expansion tank cap, not the rad as this is below the headertank coolant level. if the rad which in theory is hotter blew first the head would soon become coolant free with dire results.
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The Great Pretender
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Re: Coolant coming out of expansion tank overflow pipe

Post by The Great Pretender » Mon Jan 09, 2012 2:37 am

stuc wrote:
dave_aber wrote:The short answer is "it might be".


As a side-note, some replacement radiators DO have a vent pipe which would allow a pressure release cap to work and dump pressure - this outlet must be blocked off on a Bongo.
Why is this? Mine has a extra pipe and runs absolutely fine, surely if you have no faults this shouldnt cause a problem.
You are correct.
When you do have a problem your system will complicate it. Then is the time to question it.
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