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#1 CamMiller97

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Posted 05 February 2019 - 05:28 PM

So since I brought my mini my heater has never worked, doing a bit of research I found 2 things I can think are the problem.

1. The heater valve is broken. I’ve taken a look and the valve does move when I change from cold to hot air, could it still not be working properly ?

2. Blocked heater matrix. If the matrix is blocked up then no hot coolant can pass through, but the coolant pipes going into don’t get warm (before or after the heater valve)

So I’m pretty much out of ideas, my mini is a 1999 cooper mpi

#2 Wiggy

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Posted 05 February 2019 - 07:13 PM

When you say it doesn't work; do you mean the fan doesn't work, or it won't blow hot air?

The matrix is very prone to silting up. Check the valve is operating properly. You can see it from the passenger footwell. If it's stiff to operate, the valve is probably silted up. Sometimes the cable outer can slip so the valve isn't actually opening.

It's not very hard to remove the heater unit and flush it out. The matrix may be past it though.

#3 CamMiller97

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Posted 05 February 2019 - 07:31 PM

When you say it doesn't work; do you mean the fan doesn't work, or it won't blow hot air?

The matrix is very prone to silting up. Check the valve is operating properly. You can see it from the passenger footwell. If it's stiff to operate, the valve is probably silted up. Sometimes the cable outer can slip so the valve isn't actually opening.

It's not very hard to remove the heater unit and flush it out. The matrix may be past it though.


No hot air is blowing, but now you say about the fan, it doesn’t blow that strong, the windscreen vent blows air but not that hard.

Also dispite me seeing the valve move with changing the temperature it could still be failing ?

If no water is passing through the matrix or the valve, would to water in the pipe running through them not get hot as it just sat, or do I have a bigger issue towards the engine?

Edited by CamMiller97, 05 February 2019 - 07:34 PM.


#4 Wiggy

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Posted 05 February 2019 - 07:52 PM

Provided you have coolant in the car, and the water pump is working, there's no other real reason why water wouldn't circulate.

If you see the valve moving it's probably OK.

The pipes to the heater will take longer to get warm, if at all; as the water in the pipes isn't moving.

The fan itself is pants, so what you describe is quite normal. Check to see that all the air ducts are connected up. They're just push fit, and can fall off.

I recently replaced my heater matrix. It was completely clogged, and had rotted through.

#5 Wiggy

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Posted 05 February 2019 - 07:58 PM

Drop the coolant.

Have a bowl and towels ready.

Remove the 2 hose clamps and pull off the pipes. (this is a fiddle.)

Loosen the 2 bolts on the brackets on the bulkhead.

Remove the 2 screws that face upwards (I think), near the heater controls.

The whole thing will lift out.

Remove the 2 hose stubs.

2 screws on the side of the heater will loosen a flap.

Slide matrix out.

If you get a new matrix, you'll have to swap the hose stubs onto the new one.

Oh, and clean the valve out too.

Unhook the cable from the valve.

Remove the one bolt. (you can see it through the radio hole)

Then remove one more hose clamp and pull/twist it off.

Edited by Wiggy, 05 February 2019 - 08:04 PM.


#6 CamMiller97

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Posted 19 February 2019 - 09:49 PM

So after replacing the matrix, which was bunged up with crap, the heater still didn’t work, so ordered a new valve, taking the old one out, found it operated perfectly and wasn’t blocked, the pipe coming from the engine on the other hand was completely clogged, didn’t let any light through when looking through it out of the car. Washed that out put it back together with the old valve and now it works perfectly.

#7 Wiggy

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Posted 19 February 2019 - 11:28 PM

Good Lord, there must have been a hell of a lot of sediment to bung the pipe too!

You can bet that the radiator could do with a wash out too.

#8 ryomini

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Posted 02 March 2019 - 08:42 AM

Glad you got it sorted

but as others have suggested the route to go is to do a full flush of the system

drain the rad fluid then flush the system several times

the heater matrix same

physically remove the heater valve and check for smooth operation - grease the push rod and cable

pull the heater and remove all the dust from the fan / blower

check the pipes all connect up and and are not split

it's quite  a hassle but once it's all done the heater actually works - had the same problem






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