9 replies to this topic

[riczito]

Hi all,

 

I just tried back-flushing (and forward-flushing) my 1994 Mini's heater, by connecting two garden hoses to the inlet and outlet (in the engine compartment) and running some tap water through it. I turned on the tap, and nothing came out. Not a drop, when flushing in either direction. So apparently my heater core is clogged, right? I didn't think they could clog up that much though!

 

Am I looking at a new heater core? Or are there any other strategies I can adopt for unclogging it? Some kind of solvent, maybe?

Damn, just when winter is starting to close in, too...

 

Thanks,

Ric

[nicklouse]

you did open the heater valve?

 

more car info needed

[Wiggy]

I'm not too up on SPis, but on my MPi the heater valve was what was clogged, rather than the matrix.

 

If not, I'd remove the matrix so you can give it a good shake, and inspect it to see if its rusty.

[riczito]

you did open the heater valve?

 

more car info needed

 

Yes, I removed the valve. It's one of the inline ones, on the hose itself. I have a 1994 Mini, 1275 carb model.

 

On removing the valve, I connected my garden hoses. I have a new valve just in case, but looking at the old one, it was OK anyway.

It looks like it's the matrix that's clogged. Tried several things - I even turned the water tap up to full blast, but to no avail.

I'd really like to be able to unclog it, as those things seem to cost a fortune and they look fiddly to install too.

[Magneto]

Make sure the valve is open, if still nothing (unlikely) then remove heater, replace matrix, reinstall.

 

I've never seen one completely blocked, but I've seen plenty that were almost there and provided little to no heat. Usually if they're that bad they don't respond to chemical cleaning but there are chemicals you can buy to try once you get some water to flow thru it.

 

I think you're going to have to remove it.

Edited by Magneto, 02 December 2018 - 04:04 PM.

[grck1]

to be honest your going to struggle to completey clear it as once you get it to flow the water will take the path off least resistance and the little de clogging will occur.
To do a decent job it really needs to come out to try and clean without risking wetting the interior of the car and in my opinion £45 for a new one isn't exactly breaking the bank and will give a noticeable increase in heat output so why not fit a new one.

Edited by grck1, 02 December 2018 - 04:22 PM.

[alex-95]

I would replace it as it's probably corroded inside and may leak once you clean it out. They are pretty easy to remove, 2 screws to hold the matrix in, the clamps on the pipe and the tubes on the heater matrix need to come off to. These might be corroded but you can buy stainless ones.

[MikeRotherham]

On mine it was the replaceable metal connectors that are screwed to the matrix, the stubs that the hoses connect to, that were blocked solid with dry crud.

 

I'd start by checking them first. Stainless steel replacements aren't too expensive either.

[CityEPete]

I thought from previous cars that it would be a struggle to swap the matrix, I even bought one as mine (a 1995) was leaking and didn't tackle it for a while, turns out it was dead easy!

Undo the hoses, two screws, withdraw the matrix, clean the leaves and crap out the bottom of the heater, slide in the new matrix, screws, hoses. Refill the cooling system. Done.

[Wiggy]

Modern cars appear to be constructed like:

Body shell > Heater Matrix > Everything else.