740 air distribution box removal ‘90RHD non-AC GLT
 

Having a bit of a brick wall moment with getting the air distribution box out of my ‘90 745 GLT which is RHD with heater blower only - no air con or climate control fitted. Heater matrix has properly let go which explains the holes in the floor on photos.

The FAQ and how-to articles I’ve found here and on Brickboard all seem to relate to air con models and I can’t fathom out the process for getting mine out.

I’ve got exploded diagrams from my mate who works at a Volvo dealer but I can’t figure out whether I need to take the whole air box out, or whether I can get away with removing the bottom half of the assembly to get the core out.

Any advice from anyone who's been there before appreciated!

PDF file with photos attached.

Sorry to burst your bubble but usually if the heater matrix leaks, it does it into the drivers footwell.
What you have in the passenger side is a common rust trap.

https://i.postimg.cc/9MtgCrgQ/IMG-20...-123759208.jpg

Not sure exactly what causes it but it's fairly common.

Sorry i can't offer any advice on the heater matrix removal - so far i've been spared that task! ;) :D

Thanks - I did see that about the rot spot in the passenger floor above the outrigger somewhere. Most of the coolant was in the drivers footwell and the drivers side duct that feeds to the rear. Got a hole in the same spot as your pic on the drivers side too. Also coolant coming out of the central face vents and defrost vents and soaking all the relays and fuses. From the glimpse I’ve had of the matrix it doesn’t look happy, and neither does the water valve by the clutch pedal.
Seen the threads on the unobtainable water valve as well, happy days
Not looking like the quick turnaround I’d hoped for!

As a temporary measure, you could bypass the valve and/or heater matrix with some 15mm copper pipe to keep you mobile, i've heard rumours a Mk1 Golf heater valve fits and works which might be an option.

Does the car have a sunroof? Just wondering if a sunroof drain has caused the heater box to fill with water - also there are a couple of rubber drains on the bulkhead in the engine bay, they have a habit of getting clogged with leaves etc and causing the heater box to fill with water.

Can't find any pics of them but they're a bit of a way down on the bulkhead, one each side if memory serves. Either that or one near the brake servo - sorry to be sketchy but it's a while since i had a 740 and my 760 is different.

It’s been off the road for 3 years and I’ve got it fairly extensively disassembled at the moment, so I’m in for a penny...
It does have the sliding sunroof. One of the circuits that’s been knocked out by liquid(s) as it happens, so I can’t open the blighter at the mo. Might as well have a look at air intake blockage potential as well, would be daft not to check it. The enduring stickiness / slipperiness of the front drivers side carpet and the pink crust around the water valve are concerning me though, time to jut out the jaw and climb back in...

The most usual cause of inoperative sunroof (after the fuse) is the switch on the dash. No relays onvolved, the switch is fed with a switched +ve from the igniton switch and an earth then swaps them round on each output depending which way the switch is pressed.
If you get some contact cleaner spray, squirt it in the gap at the top of the rocker between it and the switch casing and operate the switch "viforously" in both directions then turn on the ignition and try it, you may well find it works. Try the tilt function first, easier to wind back down manually if needs be! A bit of contact cleaner and exercise on the switch should hopefully see it working again.

There should be a cover over the sunroof motor between the front edge of the sunroof hole and the windscreen top. It's held in place by two Phillips head screws at the rear edge and lugs at the front so undo the two screws and drop the motor cover down, being careful to not lose the screws. You should then see the motor, depending which one you have there will either be a square hole visible or a slot for a wide, flat bladed screwdriver to manually operate the roof.
The screwdriver slot has a pin in the middle that pops out when the motor is in the start position (sunroof closed in other words) which gives you a good reference point.

If you can get the roof open, lube the mechanism with silicone lube spray. While you have it, wind all the windows down and spray the groove in the rubber channels the glass runs in. If you're feeling enthusiastic, push the shutter aside on the locks in the doors and tailgate and squirt it in the lock barrels too. Same goes for any parts of the latch mechanisms and hinges. Simple job but very effective, especially if it's been off the road for a while!

Gives you something else to do that should give instant results while sorting the heater! Always handy to have a few little jobs like that when doing a resto, helps boost the enthusiasm again! :thumbs_up:

940 air distribution box like yours.
 

Did you ever get a reply to your post that addressed your question. I too have hit the same brick wall. How do you remove that white air distribution unit to get to the heater matrix?