Had a pm recently asking about heater matrix job and so did a search on my data base of job photo`s and came across a set of pics for a matrix swap, I most likely did around 200 of these and have covered this a good few times here. That said with new members and owners joining maybe of interest for them and a reminder for the more "seasoned members"

 

Today I still see some garages take out the dashboard to do this job, which is simply nuts...very accessible with the seat removed and doable in a morning, that said I got it down to around one hour but do not expect that on your first attempt, little tricky 8 mm fixing around the back of the pipes against the bulkhead, I used a small ratchet spanner I bent slightly and it worked every time.

 

20 years ago this was a £900 job at Nissan UK, today a couple of hundred if done for you, or the price of the matrix if you fancy it yourself, maybe an odd time to be talking about heating but ideal time to get a leaky one sorted before it gets worse or fails completely. Look for damp or wet carpet in the foot well that has a greasy feel to it and or steaming up windows when it rains or gets chilly.

 

Enjoy.

 

Jeff

 

 

 

 

 

 

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cont ...

 

 

 

Edited August 4, 20187 yr by JeffTT

On my first Z i found the leak to be coming from the gate valve next to the matrix and not the matrix itself. I removed the valve and replaced the O rings.

Yes the valve can leak also but less common, even seen a few cracked one's.

Is that valve, the one with the blue/red circle below the hot supply? Ie if it’s closed cold matrix?

Yes that is the flow regulating valve.

Brilliant. Do you know is it a simple normally closed affair that opens when 12v is supplied or does it work proportionally on a 4-20ma supply or something? Ie is it solenoid or more like a flow control valve?

Edited August 4, 20187 yr by Stephen

Brilliant. Do you know is it a simple normally closed affair that opens when 12v is supplied or does it work proportionally on a 4-20ma supply or something? Ie is it solenoid or more like a flow control valve?

 

You giving the valve a little too much credit there, its a very basic open close valve that is operated by a solid cable, however the clever bit is the cable is operated by a small stepper motor that can open / close across a variety of inputs from the heater system, there are cabin temp sensors above your head, also in the output ducts and within the heater box there are air mixer flaps so to not just regulate the water flow through the matrix but the mix of inside and outside air, there is a sun load sensor on the dash board vent, and of course the outside ambient air temp sensor and all very clever for its time but if any of the sensors are left disconnected after bumper off or dash board out, knee vents removed etc. the system cannot work correctly.

 

Jeff

Balls. I was hoping you’d say it’s a normally closed 12v solenoid. Your right the Climate control is very clever for the cars age, or over complicated and annoying is the other way of putting it.

What's the problem with yours then ?

It only blows hot. I should hook it up to consult, on board tests show all the actuators work etc, the error codes are nonsense to me. It’s a long standing issue and I have a fiddle with it then give up regularly.

Mmm, disconnected duct sensors will give an incorrect low reading and hence the valve stays open to raise the outlet temp, but of course it cannot, the valve operating cable has an outer sheath clip and return spring, any issues with these will stop the valve closing.

 

Jeff

I think temporarily il just get under there and manually close it. As you can imagine driving it in this weather with the heat jammed on, even if it’s not blowing it still raises the temp, is a little uncomfortable.

Why not disconnect the matrix inlet and outlet pipes and join them together with a bit of pipe and jubilee clips ? I had to do that when I had a leaking matrix

 

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