Coolant alarm

Technical questions and answers about the Mazda Bongo

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Northern Bongolow
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Re: Coolant alarm

Post by Northern Bongolow » Fri May 14, 2021 1:27 am

Make sure the cap on the expansion tank( not the radiator) is the correct 1.1 bar. Some fit a 0.9 these are wrong on the expansion tank.
May even be worth replacing it if your doing all the pipes,. Along with the water pump.
Gill9
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Re: Coolant alarm

Post by Gill9 » Fri May 14, 2021 2:30 am

I think it is 0.9! What difference does this have?
Thanks
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haydn callow
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Re: Coolant alarm

Post by haydn callow » Fri May 14, 2021 7:36 am

YOU MUST USE A QUALITY STAINLESS STEEL SCREW WITH A COARSE THREAD. Contact Haydn Alarms for a free replacement.....
http://www.coolantalarm.co.uk
Developer of the Mazda Bongo Coolant loss Alarm
Also BMW Clocks
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Northern Bongolow
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Re: Coolant alarm

Post by Northern Bongolow » Fri May 14, 2021 2:00 pm

When the bongo gets up to temp it creates pressure inside the cooling system, this pressure helps stop the coolant boiling. When the bongo is stuck in traffic with no airflow through the rad the fans come on to force cool it, at this point the pressure inside the system is at max, this max is just under the 0.9, that's why they put on a higher rated cap. If you have a faulty 0.9 that vents early you can get coolant loss where you are seeing it. This does also apply to a faulty 1.1 cap.
I made a cap tester pressure tank to test caps and found that about half were blowing off early.
The cap on the rad doesn't matter as it's just a bung, but the expansion tank cap is the main safety valve for the whole system and therefore should be considered a service part.
If your at the bongo bash I am bringing .my cap tester and will be doing cap tests for a small charity donation.
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Re: Coolant alarm

Post by Gill9 » Fri May 21, 2021 4:32 pm

I’ve just had the van back from the garage with ALL new coolant system pipes throughout, I’ve changed the header tank cap to a 1.1 (it was a 0.9) so fingers crossed all will be good.
I am expecting to have change/clean the screw as it has new red coolant in the system. How long should I leave it before I clean the screw?
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haydn callow
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Re: Coolant alarm

Post by haydn callow » Fri May 21, 2021 4:45 pm

I think that tank cap should be 0.9, 1.1 on the Rad if your rad is the type that needs a pressure.....


You want the tank to release before the rad.........clean the screw when the alarm takes ages to Turn off when starting.
http://www.coolantalarm.co.uk
Developer of the Mazda Bongo Coolant loss Alarm
Also BMW Clocks
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haydn callow
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Re: Coolant alarm

Post by haydn callow » Fri May 21, 2021 4:48 pm

Northern Bongolow hnows what his stuff.......but I always had 0.9 on tank and 1.1 on rad
http://www.coolantalarm.co.uk
Developer of the Mazda Bongo Coolant loss Alarm
Also BMW Clocks
teenmal
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Re: Coolant alarm

Post by teenmal » Fri May 21, 2021 10:51 pm

Both the radiator and tank cap are 1.1 ,in actual fact they are twins.
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