I'm not more confused than ever. The solenoid valve, presumably, sends current to the HCV? Given that i dont think i even have one, this might be futile. What i have is one which has two vacuum lines going into it right next to th oil filler tube. I don't see any electric leads though. After looking at the picture, i can safely say that im sure the previous owner pulle this out. It might give us a clue as to what is the problem as perhaps when the heater stopped working, he (lke me) thought the easiest solution would be to yank this part out. Put me out of my misery.

MJ

I had kinda the same issue, no heat in the cabin and found my issue to be a vacuum line screw up by the PO or someone monkeying with the heater valve vacuum lines/actuators. I also had broken heater rod clips which I fixed too.

http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/923998-heater-valve-never-opens-heater-core-why.html

please explain if you can where EXACTLY the heater rod clips are in RELATION to the other rod, which determines whether the air flows up or down (as that one i found easily enough but the heater itself and its rods i cant see anywhere on the side of the centre consul. Perhaps it is behind a black plastic cover?) Or do i need to remove the side cover of the console itself. It's starting to get cold here

thanks

The rods and metal clips will be one the left side if sitting in a US car, right where you knee would be, you'll have to flip upside down and crawl under the dash to see it, once you're upside down under the dash everything will be easily recognizable.

Those actuators that control the flaps are to the left of the inner glovebox, the picture i took are with the glovebox out, but the same procedure applies, flip upside-down and you'll see them, but easier to see if anything is goofed up by removing the glove box. Takes 8 screws and slide the glove box out, remove the hose and the light before pulling

.
http://forums.pelicanparts.com/uploa...1483045411.jpg
http://forums.pelicanparts.com/uploa...1483045411.gif

Fixing the actuator vacuum lines by the glove box allowed the plastic heater valve open, and allowed hot coolant through the heater core which provided heat.

http://forums.pelicanparts.com/uploa...1483046004.jpg

For the heating rod. i'm confused as i have actually been under there and can't find it. What i DID find underneath the steerig column was the rod and attachement for the heater FLAP which directs air either up or down. But when i looked to the right, (by the driver's knee, i couldn't see what you have in this picture). That's WHY i asked is it possible that you have to remove the side console. I'm begining to think it's not even there on my car.

For the actuators though, what should one do? Other than check the lines are connected and not cracked, what else? And what are those white capacitor looking things attached to the ends?

thanks for your patience


MJ

****UPDATE***

IN FACT that flap is actually the one people have been directing me to. I jammed it open (or at least the opposite) of what it defaults to - but the result is only a redirecion of the air (cold) from down to up.
If that helps

No removal needed, if that rod and clip are broken, by default it goes to the hot setting in the car to prevent freezing the occupants during winter driving.

Those white knobs, are really actuator motors that control your core heat and cold settings for the sliders on your hvac console in the dash which in turn apply a vacuum to your heater control valve(right next to your reference/speed sensors in your engine bay) to open/close and allow coolant to circulate into the heater core.

You can always remove vacuum line off of the heater valve and manually move that plastic lever on your heater control valve to force it open and have coolant flow through your heater core, which will produce heat.

Also if you pull the vacuum line from the heater control valve in the engine bay, put your finger over it and see if it is pulling vacuum, you'll hear it and feel it if it is working.

thanks for all that. The thing is that i DONT have that conventional HCV with the single vacuum nipple on the top of it. It's been removed by previous owner. Here's what i m guessing. Since Lebanon is a hot country, i think the PO must have done the most simplest thing to knock the hot air flow out, given that the tiny clip you mentioned was indeed broken, defaulting the system to very hot.

It's either that, or the problem is less technical and electronic, but more basic and physical and that the water is not getting in and out of the coil. This would appear to be pretty simply to check, right? Just by putting your hands on the respective pipes going in and out. I did this and i hfound that the pipe coming from the manifold at the top by the oil filler is not so hot to touch, whereas the pipe on the other side by the exhaust manifold is quite hot. But i think there is some urban myths here. After heating the car up, i think the manifold-side pipe gets hotter because of head conducting its way from the water pump and also from the exhaust manifold - possibly giving me a false idea that water is in fact circulating through the heater cooil, when in fact it is not.

I have been told that the water flows from the oil filler side into the heater coil and then out to the pipe going to to the water pump. But i find this rather bizare to say the least. Shouldn't it be the other way around? And there is a 'tap' on the exhaust manifold side. BUt does that tap open (anti clockwise) and close clockwise? It seems as though it does, but you can never be too sure.

Any thoughts?

thank you


MJ

Is there a way of uploading a photo straight from your computer instead of using a link???!!

Pictures are worth a thousand words and show us what you are talking about. No need to bypass the car's engineering cooling/heating functions just because you live in a warmer climate, that is what radiators, water pumps, and thermostats were designed for.:(


Post a picture, or better yet, revert the HCV to stock for $25 and then see if this fixes all of your problems.

Imgur.com, upload pics to it, then click the picture you want to share, then click copy on the BulletinBoard(BB) link and paste it in your response here.

Then the picture will appear like mine did.

http://i.imgur.com/Y6prOxJl.jpg
http://i.imgur.com/fDoLLDwh.png

Imgur: The most awesome images on the Internet

Here is what i have on my block. Can anyone tell me if they have seen such a hcv?

thanks

[IMG]<blockquote class="imgur-embed-pub" lang="en" data-id="a/82dUu"><a href="//imgur.com/82dUu"></a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8"></script>[/IMG]

MJ, A picture is worth a thousand words, now I have a better understanding of your problem.

Your pictures shows a normal 944 vacuum port except that the two vacuum lines are not connected. Can you find those two lines and reconnect them? Those vacuum lines control a bunch of critical stuff, including the fuel pressure reg/damper and the HCV.

Here is what mine looks like:
http://forums.pelicanparts.com/uploa...1483219553.jpg

-----------------------------------------------------------------------------------
And the HCV is located about 6 inches to the left of your pic, as shown here, between the engine and the body/firewall:
http://forums.pelicanparts.com/uploa...1483219684.jpg

MJ,

Here is a vacuum line routing diagram for the fuel system, however it does not show the HCV vacuum lines. The first thing I would do is check to see how many of these lines in this diagram are missing, or not connected properly, and try to repair them. Your car will certainly run a lot better for the effort.

http://www.clarks-garage.com/graphic...uum-line-1.jpg

http://forums.pelicanparts.com/uploa...1483222248.gif


Solenoid 1 controls the heater. When it is activated by the controller it opens and the vacuum stored in 3 operates the valve. I think it opens under vacuum rather than closes. The other solenoid selects recirculate. If you have hoses disconnected so that there is no vacuum stored in the reservoir 3 none of this will work! The reservoir is near the battery.

I think you picture is just the valve that detects that the engine is warm and opens the evaporative control valve. Should not effect the heater. Having the hose disconnected from the throttle body will make it run poorly though.

if the valve never opens, you will likely never get the air bled out of the system. part of bleeding the system requires that the heat be on high. that won't happen if the valve doesn't open

this is very useful indeed. BUt those actuators - number one and two - do they not need chamging after 30 years? How does one test them?

thanks so much
MJ

UPDATE

I have now taken the photos as a reference and made comparisons, and i can state with absolute certainty

- there is no such HVC in my engine bay against the firewall where it should be

- there is however something which looks similar UNDER the manifold which has an electric plug and one vacuum line running into it

SO, is it POSSIBLE that i have a pre 85.5 engine in my post 85.5 944? The reason i ask is that my engine is a replacement and clearly a scrap yard one, as one of the POs blew the original engine up.
Given that mechanics here think they are terribly clever by removing thermostats and anything related to having heat in the car, i am begining to wonder if i have an older spec engine as probably when the 'new' one was fitted, they removed the HVC or couldn't be bothered to put the previous one back.

Interesting point. The vacuum line coming from the vacuum reservoir goes to this unit under the manifold, but does not connect. Is this the same vacuum reservoir which the AC needs? If so please tell me as it will help in my elimination of the usual suspects as an AC repair bloke here told me that the evaporator was not working well. (Is it the same thing?).

Perhaps when the engine was swapped they just couldn't be bothered to connect that vacuum pipe from the vacuum reservoir to the HCV under manifold and that is why i am not getting hot water leave those pipes and enter the firewall (it's only warm, when engine is at full temp)
All help appreciated.

MJ in Beirut