[940 Non-AC] Heater pipework Routing?

[Anhamgrimmar]

Ayup Folks,

Just bought myself an emergency set of wheels from the scrappy for £320. Turns out they came attached to a volvo 940 2ltr non-turbo. It even flew through the MOT with no advisories so i was pretty made up.



Now its getting cold, and i was quite disapointed to discover that the heater was not working



Now i did some reading up, found the 700/900 FAQ, and pretty much figuered it'd be the heater control valve (either broken or the cable has slipped off), so i had a look:



Well, you cant tell from the picture, but the cable is attached and seems to be doing its job, moved the lever by hand when the engine was running, and still no joy. Does seem to be a bit of scale knocking about, but i've never discoverd any wet carpets, and the coolant level is pretty constant. ONWARDS!

Checked the engine bay and....


Bugger, theres no pipe into the HCV. and what i assume is the outlet of the heater matrix isn't connected to anything either. soooo:

Where is the engine coolant surposed to come from to enter the heater system, and where is it surposed to go once it exits the matrix?
Also, does anyone have a link to a new heater water valve (all the ones i've found so far claim to be for LHD 940s, does this make a differrence?)

(forgot to add, its a RHD 1992 940 GL, with a B200, no turbo, no a/c if it makes any difference)

[bob12]

What's that funny white thing .. it looks like a small ....? On my 745 with a
B200F one hose goes thro there (above the black plug) and is connected to the metal pipe extension from the water pump (you can't really see it as the connection is behind the engine.

Then you get 2 of those securing nuts/bolts/washers in a vertical line above it.

Then above that the other heater hose goes in. That one runs from the block (n/s back end) below the inlet manifold between 3 and 4 injectors).

[Anhamgrimmar]

AHah! thats how its been done then. there's a rubber hose going from the water pump metal pipe, and it loops round the back of the head and comes into the block just below the intake manifold!

right, so just to make sure in my head, the pipework should be:

metal pipe (from the water pump) ->rubber hose to the water control valve (low down on the drivers side of the bulkhead)

output from the heater matrix (higher up, and towards the middle of the bulkhead)-> rubber hose to an inlet underneath the intake manifold.

Any leads on a water control valve? looks like everyone says that a Motorcraft YG136 Heater Valve is a drop in replacement, but it doesn't look like what i can see of the one fitted (can't see any vacuum gubbins on the one i have)

[bob12]

Sounds OK to me. Over past two years or so several good threads in this section on valves/fixing and sourcing suggest us Google as search button hopeless - best of luck - Bob.

[Ian21401]

Image 3 of the valve looks the same as my 1992 940 estate with a B200F engine.
Re replacing the heater control valve, have a look at the thread "940 Heater Control Valve" dated 5 February 2012, started by jim f. The part number on the Volvo valve I obtained from my main dealer is 94 47 892. The part number on the old valve was 35 37 062. They both outwardly appeared the same.
The hoses on my car car are the same as described by bob12 and you appear to have got the right idea. The reason my valve had been leaking was that the input pipe through the bulk head had been damaged my someone in the past and the hose did not seal properly. If the previous owner of your car has bypassed the heater then I suggest that either the valve was leaking or worse, the heater matrix was leaking. I'm not sure how it could be done but is it possible to pressure check the heater matrix before connecting up hoses etc. I'm sorry but at the moment I cannot locate the part numbers for the heater hoses.

[Ian21401]

It was back in 2008 when I replaced my heater control valve so my memory was a bit hazy. I've just had a look on my car. The hose from the metal pipe to the water pump is connected to the top outlet from the heater. The hose from the cylinder head is connected to the bottom outlet from the heater which I think is the one from the heater control valve.(The one shown in your 4th image. I've checked back in my receipts. In 2008 the replacement heater control valve from my main agent cost £48.80 ex vat. (part no.VO9447892). I don't think that I replaced the hoses so I don't have any info.about them.

[Anhamgrimmar]

Ah, cheers matey.not got round to re-connecting everything yet, but i'm going to head to the Factors on monday to see about a new valve, and some hoses.

[barkster1971]

I bought a hcv from the states off a Chevy Astro van for £29. Didn't take too long to get here and genuine hoses from FRF for £48. The coolant comes out at the back of the head, through the valve and into the top inlet to the heater matrix (from right to left in the pic). It then comes out of the bottom back through the valve (left to right) curls round 180 degrees and goes under itself, turn 90 degress and goes under the exhaust manifold to the pump. The Chevy valve allows flow through the head instead of when heat is selected and helps keep the cylinde rhead temps down.

[Anhamgrimmar]

Right then, seeing as how i hate it when you search the web for a problem, find someone with the same symptoms, and they've never updated whether the advice worked...

I've managed to bodge the previous owners bodge, and now my heater works!


Ordered a HCV from ebay and after a brief stuggle, i managed to get the old one out, and discovered it'd snapped at the 'pipe' that goes through the firewall.

Took a long time to get the new one in, and it still didnt look right. i then discovered that LHD and RHD volvo 940s have valves that are a mirror image of each other (kinda obvious now, but...), and i couldnt get the control cage thingy to fit again. oh well, full uncontrolable heat is better than no heat at all. ONWARDS!

Reconnected the top heater connection to the metal pipe that leads from the waterpump (good shout by the way, cheers for that), and got a generic length of heater hose from the factors to connect the bottom heater connection, to the back pssenger side of the head, till i can afford a proper volvo hose.

Happy da.....oh. wheres all the coolant gone? turns out if you forget to reconnect the new HCV to the heater matrix, all the water falls out. whoopsie


reconnected it all up, refilled the reservoir, and ran it at idle until it hit temp. lovely lovely heat!

Now i can afford to take the time to collect parts and do it right, rather than freezing my ass off. Cheers folks

(incidentaly, barkster, does that 940 have aircon of some description? i'm only asking because the top hose on mine is one long hose, rather than having 2 lengths and a vacuum hose in the middle)