Header Tank Cap?

Technical questions and answers about the Mazda Bongo

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Boxermad
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Header Tank Cap?

Post by Boxermad » Sat Oct 04, 2014 7:55 pm

I've just bought my first Bongo (Bertie) and we have had a few overheating problems. I told the garage I thought the water was low and they topped it up for us so as we are driving home and she spat out her water and got a bit hot. We got this sorted and she hasn't overheated again but we are losing a bit of water. So far I've only driven about 70 miles and we lost about a liter.

This morning I got my first newsletter and in there it says the header tank cap must be rated at 1.1 bar. Bertie's is 0.9 bar. Would this cause her to throw out the water?

It's great to be in the club (did I just type that?) and I'm looking forward to any advice.

Caroline
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mikeWalsall
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Re: Header Tank Cap?

Post by mikeWalsall » Sat Oct 04, 2014 9:20 pm

It it advisable to use the proper radiator / header tank caps .. as like a kitchen pressure cooker .. it raises the boiling temperature of the water ..

Saying that I lost the one off the (plastic) header tank .. as I only had a 0.9 bars to hand (from motor bikes) so I fitted that .. always meaning to get a 1.1 bar one .. needless to say I never did .. but the 0.9 bar as functioned OK for me ..

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francophile1947
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Re: Header Tank Cap?

Post by francophile1947 » Sat Oct 04, 2014 9:29 pm

A litre in 70 miles is hardly using a little :shock: - you definitely have a leak that needs fixing straight away.
A lower pressure cap will let the coolant boil at a lower temperature than normal but, if that's your problem, you would expect to hear it boiling and see it leaking.
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Boxermad
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Re: Header Tank Cap?

Post by Boxermad » Mon Oct 06, 2014 10:29 am

mikeWalsall wrote:It it advisable to use the proper radiator / header tank caps .. as like a kitchen pressure cooker .. it raises the boiling temperature of the water ..

Saying that I lost the one off the (plastic) header tank .. as I only had a 0.9 bars to hand (from motor bikes) so I fitted that .. always meaning to get a 1.1 bar one .. needless to say I never did .. but the 0.9 bar as functioned OK for me ..

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Thanks Mike
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Boxermad
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Re: Header Tank Cap?

Post by Boxermad » Mon Oct 06, 2014 10:31 am

francophile1947 wrote:A litre in 70 miles is hardly using a little :shock: - you definitely have a leak that needs fixing straight away.
A lower pressure cap will let the coolant boil at a lower temperature than normal but, if that's your problem, you would expect to hear it boiling and see it leaking.
Originally when we collected the car it was blowing water out, after bleeding this seems to have stopped. Looks like more investigation coming - luckily I won't need her till this weekend
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