cooling system airlocks

[Simon Jones]

I believe the rear heater was a factory option, but fitted to pretty much all vans, so in theory it should work fine either way.

[missfixit70]

I'd be interested to see the set up for a front heater only factory system if anyone's got access to one with a camera, or close enough to me that I can come & have a poke around?

[ScubaBongo]

There would need to be side by side tests of both the original system, and the modified "no rear matrix" system before any comparative data could be compiled.

If the ommision of the rear matrix equates to a higher average running temp (due to a certain percentage loss of heat sink), and possibly an increased pressure, then it's probably not wise.

Having said that, i don't recall a wellhouse vehicle suffering from over heating issues, so it may work just fine.

It would be interesting to see what (if any) pressure/heat changes could occur though.

could you not reclaim this lost area of heat sink, either by fitting a larger/more efficient radiator (space allowing) or refitting the 2nd heater matrix in a place where it would cause less trouble (like next to the rad somewhere maybe).

Sounds like a lot of hassle/fiddling though doesn't it? (Although cracked cylinderheads are somewhat troublesome too!)

Maybe someone could make up a kit and start a cottage industry...

[redshadow]

have emailed wellhouse to see if they can shed some light, will keep ya posted if i get a reply

[apole]

Wellhouse do remove the rear heater and air con system to make way for the onboard waste tank that fits in the space reclaimed.

I'm sure not all bongo's have rear heaters so I'd be very surprised if mazda relied on a rear heater matrix that is unlikely to have much/any airflow in the heat of summer, as an integral part of the cooling system design.

I have not had any hotter running since bypassing mine, as to bleeding, well that was the first time I'd bled mine myself so I couldn't comment on whether easier or not.

I'm tempted not to bother reconnecting mine simply because I don't use it, the matrix can leak (as I suspect mine was) and the 2 cooling hoses supplying it are exposed. I was never planning to leave this bypassed but there is the point that it's more to go wrong, and my car does warm up faster which is good for the economy and engine life as most engine wear does occur during warm up.

Are there any diagrams on lushprojects that may help maybe?

If we do find out that it is needed to help cooling, then I'd be first to get it fixed but as I said I'd be surprised and Wellhouse have done many, I don't think they would if it was known to cause issues.

I'm keeping a keen eye on this one as overheated engines are not cheap !!!

Andy

[dandywarhol]

The rear matrix (when fitted) is always "on" i.e. coolant going through it. Its the airflaps which send the heat out to the van.

The only Bongo I know without a rear heater as standard is the guy in Inverness who hires them out - he fitted an Eberspacher in the space.

[redshadow]

Just got a reply from Wellhouse, "They have always been OK for us on the front heater/aircon," was the answar. but also said if i aint broke dont fix it
but could be something for the future for me.

[Trouble at t'Mill]

I'd be very, very, very surprised if removing the rear heater had any adverse effect whatsoever on the overall cooling system. But whether it's actually worth removing - I dunno

On a slightly different note, has anyone tried adding the available rad additives which 'wets' the coolant and improves efficiency? Clearly the Bongo doesn't normally need any help with cooling, but a 'wetter' coolant would be less likely to hold air bubbles/pockets and might even be persuaded to expel them. Pure speculation on my part, tho'!

A 'wetter' coolant has a lower surface tension, and it makes better contact with the surfaces inside the cooling jacket and matrices etc. Imagine a droplet of water sitting wobbling on a polished surface. Add a tiny speck of detergent, and the surface tension which holds the water as a raised droplet breaks down, and the water will flow over the surface. Air bubbles trapped in the liquid will also be held in this surface tension 'skin', so I suspect adding a wetting agent might help to break any bubbles into tiny 'fizz' which could be expelled with the normal coolant flow and out the expansion tank.


As I said, pure guesswork!!!

[hogggman]

i`m thinking of changing the coolant in our v6 before summer,and i read these threads with interest.just got to summon the courage to tackle it now.
jamie

[apole]

Just a note to say I've thought about the coolant enhancers before so I've started a new thread on this to see if anyone has experience with these products. Worth finding out.

This thread can be found here - http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=29570

[missfixit70]

Right, having had a poke about underneath & looking at lushprojects - http://www.lushprojects.com/bongopartsm ... mgno=.html



I'm thinking of removing the pipework rear of the two drawn on arrows at Z & Y, effectively replacing the t pieces with elbows, thus eliminating the rear heater from the circuit, as I'd imagine it to be with the non rear heater factory set up.
Any thoughts?

[apole]

Hi Kirsty,

When I did mine due to a leak and to get me back on the road, I simply took off the rubber hoses that went from two metal pipes under the drivers side (they feed and return from the heater matrix, and then used on of those hoses (cut shorter) to directly connect the two metal pipes in the coolant circuit.

There may well be a better way to remove more pipework from the equation but the above was very simple and quick, then you just have to spend the time bleeding the system.

Regards

Andy

[missfixit70]

Hi Kirsty,

When I did mine due to a leak and to get me back on the road, I simply took off the rubber hoses that went from two metal pipes under the drivers side (they feed and return from the heater matrix, and then used on of those hoses (cut shorter) to directly connect the two metal pipes in the coolant circuit.

There may well be a better way to remove more pipework from the equation but the above was very simple and quick, then you just have to spend the time bleeding the system.

Regards

Andy

This is what I'm working towards, the way I've described above seems to be the logical way of doing it, especialy as the t-piece at position Y has a tiny weep with corrosion, just starting, which is what has made me revisit this idea.

[missfixit70]

The flow diagram on page 6 of the overheating factsheet - http://www.igmaynard.co.uk/bongo/member ... eating.pdf shows the whole system a bit clearer, seems to back up my thinking, in that the rear heater is basically an add on & the whole rear sytem can be removed from the rest at the T pieces.

[mayk19]

There would need to be side by side tests of both the original system, and the modified "no rear
Having said that, i don't recall a wellhouse vehicle suffering from over heating issues, so it may work just fine.

my wellhouse conversion did ! But it wasnt to do with the rear heater removal. Although, after my overheating incident I replaced most of the hoses. Where Wellhouse had removed the rear system they had bent some of the existing pipes at very accute angles to meet back into the cooling system... I had this removed and replaced with a smoother transition pipe. Also, one pipe they had blocked off was seeping.