Heater matrix mystery 'gunk'!

[lucklesspedestrian]

Hi

Mentioned in a previous post that my daughter's newly aquired Bongo wasn't putting out much heat even at the full 32c setting. She put it into a local garage mentioned here as one of the 'Bongo friendly' ones and they quickly concluded it is likely to be the heater matrix so the plan was to flush it and then if that didn't work then maybe a new one might have to be sourced (easy enough, looks like they are available for £120 and some useful guides on here re how to replace them).

She got an update today from the garage that there was a lot of 'brown gunk' coming out of the matrix when flushed which they though looked like sealant of some kind (remember I'm relaying this 2nd/3rd hand!) and her impression was that the garage were a bit mystified as to how it got there.
On the one hand it sounds good that they have identified the likely cause of the poor heating (I'm guessing a matrix full of brown gunk would result in poor heating!) But obviously I'm a bit worried as to what the 'sealant' that's in there is doing there in the first place!

It's all going to be speculation of course but I'd be interested to hear people's thoughts?

Cheers
Steve

[BongoBongo123]

I only know Bongo basics round these parts but as a pure guess, could it be remnants of someones old Radweld quick fix solution ?
Not sure if water that is in heater matrix sees the main radiator in the system/they might be seperate systems.

Anyway I hope it is a quicker and cheaper resolution to the problem rather than the opposite.

[mikeonb4c]

Welcome. Is it a diesel? Does the header tank show any sign of rust staining. Can the mechanic advise on the consistency of the sludge (rusty but not sticky? stivky/gluey?). I believe that mixing old glycol type antifreeze with organic OAT antifreeze can result in gunk formation. Another possibility is someone added something to fix a leaky radiator (Radweld) or even symptoms of a blown head gasket.

[lucklesspedestrian]

Sorry, should have said, it's the 2.5 V6

Yes I was worried about the head gasket but coolant levels seem steady, no overheating, no excessive white smoke and no mayo under the filler cap. Hopefully the garage would suss that one out pretty quickly.

The radweld thing makes sense, if it looks like sealant then someone sometime must have tried to seal it! Again, hopefully the garage would spot a leak and put 2 +2 together.

It's a bit annoying being 50 miles away from where the work is being is done and hearing about everything 2nd hand. Suppose I just have to trust the garage. We got the Bongo for a good price, it's a 17/18 year old vehicle so if it does need a heater matrix then I suppose we have to be philosophical and just accept that there was always going to be something. Plus it would make for an unusual prezzie to unwrap on Xmas morning!

[Doone]

Brown rust and muck is not that uncommon when the Bongo matrix is flushed. If a weak solution of antifreeze has ever been used, it would have less corrosion resistance and more rust could form. This would go through the 'full flow' coolant pipes and gather in tiny fins of the radiator and matrix. So what the garage is seeing may (hopefully) be nothing to worry about. Fingers crossed for you.

[lucklesspedestrian]

I shall of course let you know how it all ends (it never ends though really, does it? )

[teenmal]

What was the result on the thermostat examination/test.?

Take care

[lucklesspedestrian]

What was the result on the thermostat examination/test.?

Take care

Took it out and cleaned the build up of dust off it but sadly no improvement in the heating.

[teenmal]

What was the result on the thermostat examination/test.?

Take care

Took it out and cleaned the build up of dust off it but sadly no improvement in the heating.

Sorry meant coolant thermostat.

[lucklesspedestrian]

What was the result on the thermostat examination/test.?

Take care

Took it out and cleaned the build up of dust off it but sadly no improvement in the heating.

Sorry meant coolant thermostat.

Didn't know there was a coolant thermostat. I remember your post about the coolant temp which made sense i.e.

The first thing I would check with a new purchase is the running coolant temperature ( Nae hot water Nae hot air).


but didn't realise there was an actual coolant thermostat. Anyway, it's all getting beyond my paygrade and we'll let the garage figure things out....watch this space!

[mikeonb4c]

The head gasket thing is mainly a diesel Bongo problem. But stuff like leaky radiators is something that definitely goes with the territory with an aged Bongo. Main radiator is not ruinously expensive to replace, and many have had their main radiator start to leak where plastic joins metal - mine went at around 19yrs old. Make sure garage follow proper procedure for bleeding a Bongo after refilling - its crucial they do it right. Good luck and keep us posted.

[lucklesspedestrian]

The head gasket thing is mainly a diesel Bongo problem. But stuff like leaky radiators is something that definitely goes with the territory with an aged Bongo. Main radiator is not ruinously expensive to replace, and many have had their main radiator start to leak where plastic joins metal - mine went at around 19yrs old. Make sure garage follow proper procedure for bleeding a Bongo after refilling - its crucial they do it right. Good luck and keep us posted.

I know, I was surprised to see the rad is less than £100 most places.

re: Make sure garage follow proper procedure for bleeding a Bongo after refilling - its crucial they do it right.

That to be honest is where I start to have anxiety attacks at 3.00am. I struggle with the idea of suggesting to a garage how they should bleed and refill the system when that's meant to be their area of expertise. I totally accept and value the accrued knowledge on this forum and I know that the Bongo has it's own idiosyncracies but I still hestitate to phone up the garage and say "don't want to tell you your job mate but it says on the internet etc etc". The garage in question is listed in the members section here as 'bongo friendly' but goodness knows what that translates to in terms of actual experience. If the flush doesn't do the job I might have to bite the bullet and find some way of diplomatically asking the question!

[lucklesspedestrian]

Well thankfully flushing out the heater matrix did the trick apparently. The mechanic was a bit concerned at the amount of gunk coming out of it but it's done and according to my daughter the heater is now much improved. Apparently the mechanic had some concerns that the amount of gunk which was flushed out might mean that the matrix won't last too much longer but at least if it does go at some point in the future (I'm guessing I watch out for wet in the cabin/footwell and obviously no heat!) then we know what the problem is likely to be, that the actual part is readily available and not too expensive and most importantly that I've found a garage local to my daughter in Edinburgh that knows its way around a Bongo.

Thanks again for all the helpful input here.

[Bob]

Well done, and great to find a garage near you for service work.

Bear in mind if the heater matrix does fail, along with the symptoms you suggest, you will loose all the coolant so must stop and get Bongy recovered for repair.

Before you cook the head.

[mikeonb4c]

Great news and glad its sorted. And you have some thoughts from here on what contingencies to maybe plan for down the road.