SIMPLE 940 heater matrix replacement! Read this first!

[woodyjames]

Hello all,

Wanted to share my story in case it saves someone else a lot of time.

I have a 1997 940. No A/C, no vacuum knobs. LHD. Coolant leaking into drivers foot well so I assumed heater matrix leaking.

Came across write ups from people here and on other Volvo forums describing the process in detail. As I assumed and dreaded, a pretty huge job with a lot of the dash coming out to get to it.

I cross checked before starting- with my car it sounded definite that this was the process I had to do.

6 hours into the dash later, I realised that mine wasn't the same as either of the articles.

I have read people saying that only some of the 'early 940's' had this setup, - the same heater matrix as a 740 - and with the control flow valve on the interior side if the bulkhead, next to the heater core. Obviously, this is not true.

Anyway, before starting the job, do this FIRST to see what type you have!
Remove the plastic panel above the pedals, - then you will be able to see the type you have. If you see the heater matrix and the control valve with 13ish cm long coolant pipes linking them and the top one direct to the bulkhead, you have a very easy job.

If yours is like this YOU DO NOT HAVE TO REMOVE ANY CENTRE CONSOLE / DASH.

I found one guy explaining that he had done exactly the same as me so thought i'd add my own- hoping that someone searching finds this, or his, before making the same mistake following the other articles which come up high on google search results.

It created about 10 - 12 hours work dismantling the dash, ducting etc and re assembling, which DIDN'T NEED TO BE DONE!

Turned out that mine was just leaking where the bottom hose went onto the core- the heater matrix itself was fine anyway! And if I had removed the plastic panel above the pedals i would have seen this was the case immediately.

Anyway, to inspect / replace the heater matrix / core, all you have to do is this:

Disconnect negative side of battery.

Remove water pipes going through bulkhead in engine bay. While you're there, disconnect the throttle cable. (only if LHD drive car)

Assuming you have already removed the plastic panel which lives above the pedals, remove the accelerator pedal. (only if LHD drive car - if RHD remove the clutch pedal instead!)

Undo the single torx screw that faces you which holds some electronic gubbin box above the throttle pedal, but leave it plugged in. Then its slides off towards back of car.

Undo the 4 coolant pipe connections, and 2 control cables.

Rotate the water flow valve 90 degrees, gently pull it and it will pull out of the bulkhead. (it’s a bayonet connection- this stumped me for a while)

Now- there’s a small torx top and bottom of the matrix plastic cover plate.

Remove them with and the matrix will be able to just slide out.

Done!

I am a fairly new Volvo owner, and am not registered with any of the other Volvo forums. If anybody could help out pasting this onto the other Volvo forums they are registered with hopefully more people will see this, and not go through the unnecessary NIGHTMARE that I just did.

Thanks!
Woody

[griston64]

I know this will be obvious to many but this won't translate to a RHD car.

[woodyjames]

Originally Posted by griston64

I know this will be obvious to many but this won't translate to a RHD car.

Amended - thanks mate

[kiloran]

Thanks - I think mine might be like this too - '93, non-ac manual 2l NA. Certainly when I've looked at the matrix with the kick panel off I can see both connections and it looks like it would slide out with the clutch pedal removed. The heater circuit is probably the biggest source of concern for me about the longevity of the car, as RHD heater valves and matrixes are no longer available.

[griston64]

Originally Posted by kiloran

Thanks - I think mine might be like this too - '93, non-ac manual 2l NA. Certainly when I've looked at the matrix with the kick panel off I can see both connections and it looks like it would slide out with the clutch pedal removed. The heater circuit is probably the biggest source of concern for me about the longevity of the car, as RHD heater valves and matrixes are no longer available.

There is a fix with the MK1 Golf heater valve and you can get a new matrix from Nissens

[Steve940estate]

Originally Posted by kiloran

Thanks - I think mine might be like this too - '93, non-ac manual 2l NA. Certainly when I've looked at the matrix with the kick panel off I can see both connections and it looks like it would slide out with the clutch pedal removed. The heater circuit is probably the biggest source of concern for me about the longevity of the car, as RHD heater valves and matrixes are no longer available.

I have taken the matrix out of my car by removing the clutch pedal. It should come out easily on an auto car as long as it clears the large auto brake pedal.

[lnparry]

Hi folks and thanks to Woody for the original post.

Has anyone tried this quick fix, or know if it will work, on a '97 manual car with AC and vacuum heater controls?

Cheers,
LeeP

[Laird Scooby]

Originally Posted by lnparry

Hi folks and thanks to Woody for the original post.

Has anyone tried this quick fix, or know if it will work, on a '97 manual car with AC and vacuum heater controls?

Cheers,
LeeP

The heater valve will be under the bonnet if it's vacuum controlled Lee. After that your best bet is to crawl into the footwell and look up to see what access there is to the heater matrix. Easier on an auto obviously as no clutch pedal in the way

[Tim1980]

Brilliant, I'll definitely be trying this out!

[Laird Scooby]

Originally Posted by Tim1980

Brilliant, I'll definitely be trying this out!

Don't forget the OPs article was written from the perspective of the owner of a LHD car Tim, certain things may not translate to RHD cars.