Bongo Fury

OK, after changing all hoses Bongo has been running fine.........until today. Typical as I'm all loaded up for Bearded Theory tomorrow.

Driving home after an early finish I notice the heater is only warm again...then it goes cold
I pull over instantly and pop the bonnet open.

Just as I did this the bottom heater hose blew off and sprayed my hand with boiling coolant

The good news! I pulled over directly opposite a garage.

So I borrowed some tools (can you believe I accidentally left my tool kit out of the Bongo loading it up last night!).

Removed heater intake, fan etc.
Took the blown off lower heater hose and attached it to the metal pipe where the top heater hoses attaches to. Heater hence bypassed.
Easiest bleed ever!!!

Drove home...all fine.
Attached length of 5/8 hose to heater matrix and blew. Completely blocked both ways...completely.

My diagnosis.
All my matrix suspicions were correct. It's gunked up. Sometimes there has been partial flow, especially after the speed bump freed 'something'.
As it's gunked rust particles have collected in the most restricted area-the matrix- and have built up enough to block it.
Pressure has built up upon complete blockage and blown the bloody hose off.

Apart from lack of heater all seems fine now, so we shall go to the festival.

My solution. Attach a hose to each end of the matrix. Put in some rad flush or caustic soda leave a while...then backflush. Repeat if needed.

If I can't flush it, it's a case of no heater until I can get my hands on one.

Anyone changed one?

I was 90% sure that was the case with yours, can't help with fitting other than to say it's inside behind the dash, looks like you may have to take some photos & do a how to

I'm hoping a hardcore flush might sort it as it looks like the dash has to come off to get to the matrix! plus they are like gold dust...apparently

Anyone driven around with a bypassed front heater?
I realise I have one less thing to allow the coolant to ..well, cool. Also there will be a little less coolant.
However, at least it's flowing now.

Seems OK. I left it ticking over for a good 40mins and then revved until the fans came on.

Now runs slightly hotter but sits at a very constant 80c at the top hose. fans kick in at 87 and knock it back down to 80 when they cut off.

Gets a little hotter when it has to work-hills etc. but not 'overheating hot'.

Sorry to bump this but.....

Anyone got any tips on flushing the front heater matrix before I attempt it at the weekend?

It is completely blocked...no flow through whatsoever....
I've attached a hose either end and blown as hard as I can each way and it's not even letting air through....no wonder my cooling system has been acting up again.


Just for the record, if anyone has to bypass the front heater matrix..
Bongo is behaving better most of the time. Modded temp gauge sitting at 12 'o' clock.
However, if it has to work, hills or queueing etc. it get's hotter- due to less coolant and the loss of the cooling effect of the matrix I pressume.

im fairly sure ive heard you remove the matrix from the nearside cubbybox,and its not as bad a job as you think,but im with you try to clear it in situ,i would probably remove the original flow/return pipes,put on some replacment pieces 3 foot long,then try a dilute castic/water mix.dont leave it in more than 5 mins though.try a bit of gentle air pressure the wrong way round the system,system works at just under 1 bar so keep under that,that may help.watch your eyes with the caustic!!!

Exactly what I've been doing but with water only.

I've managed to backflush some crap out but it is still almost blocked- say 90%. Some rust particles and some 'globules' came out.
I can only assume the so called importer I bought it off(known in my house by a selection of Anglo-Saxon terms) had just topped up the Japanese antifreeze with European stuff...cheapest I expect....hence globules. These are not particulate, more like the lumpy bits in bad gravy They squash between thumb and fingers but do not dissolve in water.

Another thought.....is the matrix aluminium?
If so, Caustic Soda + Aluminium = hydrogen

Yes, it will give off highly flammable Hydrogen gas....smokers be warned

I have replaced the front heater matrix, from memory it's not too bad a job. The worst part is removing the linkage for the heater flaps. There is no reason to take out the dashboard.

redalan1971 wrote:I have replaced the front heater matrix, from memory it's not too bad a job. The worst part is removing the linkage for the heater flaps. There is no reason to take out the dashboard.

Yeah, I've just taken the left cubby thingy off and had a look...not as bad as I first envisaged.

However, after 2 hours of physically blowing water through I have a little more flow. I mean topping up with a funnel and then blowing into the hose I've attached- no chance of reaching the parking space with a hosepipe

I'm now thinking of sticking some neat radflush in it. Ye Gods it is certainly clogged up to hell.

If the matrix is choked there's a fair chance the radiator is too..............

dandywarhol wrote:If the matrix is choked there's a fair chance the radiator is too..............

Yep, one on order. Best get it all done.

Choked isn't the term for it. It was completely blocked, but now I get a trickle through.

Any thoughts on sticking some radflush in in 1/2 pint of water for half an hour?

Mountain wrote:

dandywarhol wrote:If the matrix is choked there's a fair chance the radiator is too..............

Yep, one on order. Best get it all done.

Choked isn't the term for it. It was completely blocked, but now I get a trickle through.

Any thoughts on sticking some radflush in in 1/2 pint of water for half an hour?

The terms pi55ing into the wind & a fart in a thunderstorm spring to mind. Anything strong enough to shift sumat that well blocked is gona eat into the core too I reckon, so you may clear it but a week later it'll probably go pop. Just my thoughts

I hope not Kirsty

It would depend on what the matrix is made of and what chemicals are used to flush. If the chemicals dissolve the gunk only it should be ok. I have removed a lot of gunk and particles with just water. The idea was to free it up a little before adding anything chemical based.

I'm presuming the matrix is aluminium....can anyone confirm this?

If so, caustic soda would eat into it if left too long. This is why I was opting for radflush as it's supposedly aluminium friendly. It would be interesting to know what's in these proprietary products as I could put my chemist head on.......

Anyway, I'll have to take the risk. If I do get a matrix leak I will have to bypass it again until I manage to locate one. Meanwhile a new rad can only improve things.

Pretty sure it's ally, good luck with it.

Yeah, chances are it is, so hopefully a ally safe flush should leave it intact. I'm a little more hopeful after partially unblocking it with water alone.

Decided to use the Holts 2 stage flush as the second bottle acts as a neutraliser and should stop anything being eaten away!!
I think I'll start off with a weak solution and build up if needed.

One day I'm going to have a 'my cooling system is working properly' party

Mountain wrote:Yeah, chances are it is, so hopefully a ally safe flush should leave it intact. I'm a little more hopeful after partially unblocking it with water alone.

Decided to use the Holts 2 stage flush as the second bottle acts as a neutraliser and should stop anything being eaten away!!
I think I'll start off with a weak solution and build up if needed.

One day I'm going to have a 'my cooling system is working properly' party

If you can find a way to pump it (or gravity feed then put the contents of lower bucket back in at the top) around the matrix the product should access all areas better and get its job done quicker. Good luck Hoskins