Why does the front heater blow very hot when it's set cold?

Technical questions and answers about the Mazda Bongo

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paulim
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Re: Why does the front heater blow very hot when it's set co

Post by paulim » Mon Jun 09, 2014 6:18 pm

Thanks for all your replies. I have had a look at the links by the driver's feet and without the photo posted by Mike Walsall (thanks Mike!) I wouldn't have known but one link is missing because the attachment on the white plastic bracket is broken

Image

I'll get that fixed shortly, but does that just redirect air (at whatever the set temperature is) to different places, as it seemed to open and close flaps based on the direction slider rather than the temperature control?

I couldn't really see where to look for the flap under the bonnet, but it did look as though the inlet is right by the top of the radiator, so much heat from there might get sucked straight into the cabin. Does that mean the intake for the rear cabin is in a different place, as that was blowing cool (ambient) when the front was blowing hot?

Thanks again for your help.
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Re: Why does the front heater blow very hot when it's set co

Post by g8dhe » Mon Jun 09, 2014 9:46 pm

The lever under the bonnet simply diverts the air intake from the front of the vehicle to an intake by the bulkhead, the lever can be seen above between the yellow arrows poking up.
The white disk on the drivers side (61-A70 below) controls the flaps that choose the air vent for the air to come out of and the servo and link under the passenger side (61-A60) of the same air box controls the amount of heated air added to the incoming air. See http://lushprojects.com/bongopartsmk2/c ... mgno=.html
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paulim
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Re: Why does the front heater blow very hot when it's set co

Post by paulim » Mon Jun 09, 2014 11:05 pm

Umm, I somehow managed to post the same question twice... Anyhow, I checked this mechanism and it seems OK. Good to know it's there - thanks.
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Re: Why does the front heater blow very hot when it's set co

Post by paulim » Mon Jun 09, 2014 11:26 pm

I don't seem to have a lever, useful as it would be. I think it would be where the pink arrow is.

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And I assume the yellow arrow is pointing to the air inlet, which is indeed just a few small centimetres from the top of the radiator.
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Re: Why does the front heater blow very hot when it's set co

Post by wonkanoby » Tue Jun 10, 2014 1:03 am

that one just effects if fresh air coming in cab or if cabs sealed of

hot and cold etc is big circular on one drivers side
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Re: Why does the front heater blow very hot when it's set co

Post by g8dhe » Tue Jun 10, 2014 9:04 am

No the lever is to the right of the Fuse box, down the side of the air intake, on my photo above just above the middle yellow arrow.
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Re: Why does the front heater blow very hot when it's set co

Post by Driver+Passengers » Tue Jun 10, 2014 9:14 am

Paul - your yellow arrow points at the engine air intake which is behind the driver's headlight (then routed through filter under driver's seat, round back of engine to turbo, etc...). Geoff's yellow arrows point at the cabin air intake which is plumb in the center of the under-bonnet, directing air back and down towards the heater fan (you can see it if you remove the plastic scoop).
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Re: Why does the front heater blow very hot when it's set co

Post by paulim » Wed Jun 11, 2014 8:58 pm

No lever on my van. The chap in the garage suggested that the heater control was fine and not missing a link, that the additional link is for the climate control version. I'm not convinced, as I have the broken end of the control arm and remember throwing away what (with retrospect) must have been the link. Anyhow, I didn't have time to discuss and I'm off to Le Mans tomorrow. Aircon recharged and working again though (last charge was three years ago).
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Re: Why does the front heater blow very hot when it's set co

Post by mikeWalsall » Wed Jun 11, 2014 11:30 pm

The fresh air intake for the heater is the flat plastic ducting ......

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...... attatched to the square heater blower box ..

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Re: Why does the front heater blow very hot when it's set co

Post by rita » Wed Jun 25, 2014 6:06 pm

g8dhe wrote:It seems to vary mine isn't a Northern Japan one but has the adjuster it also has a filter in the air intake which others don't have;
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Geoff, should that battery clamp not be on the Front of the battery.?
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Re: Why does the front heater blow very hot when it's set co

Post by Sparticus » Wed Jun 25, 2014 10:10 pm

Hi Paulim
Looks like you're having the exact same problem as me.
My linkage in the drivers side foot well was broken, it's a disaster in the winter as you can't demist. You are right, this only affects the flaps, not the temperature

So far I've re-gassed. and cleaned the heat exchanger after taking off the ducting and the fan.

Here's my thread on the problem: http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=66413

Tomorrow, I'm fitting new gaskets around the heat exchanger, as mine are non-existent. And taking apart the the cover and mechanism in the passenger foot well, as I cannot see it moving. Not sure at what cycle it does move (As I'm not sure what it does) but surely it should move at some point.

I wondered what the lever does to the left of the ducts under the bonnet, but from this post, now I know - Just got to figure out which way it should be set for Summer running!
Reality looks interesting from this distance.
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Re: Why does the front heater blow very hot when it's set co

Post by Sparticus » Wed Jun 25, 2014 10:16 pm

Ahh, sorry g8dhe
Just re-read this topic, you've explained clearly what happens on the passenger side. - Will check for movement whilst changing the temperature
Reality looks interesting from this distance.
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Re: Why does the front heater blow very hot when it's set co

Post by g8dhe » Thu Jun 26, 2014 9:39 am

Rita, on that battery tray it doesn't matter,in fact when it was changed I used the base clamp instead.
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