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Car Forum / Saab Cars / June 2005Hot air constantly
Hi all. I have just purchased my first Saab two weeks ago, a 1990 9000 Turbo, I love it already! The person I purchased it from had by-passed the heater core because hot air would always be entering the cabin. The AC works fine when the core is by-passed. My question: is there flap (or flap motor) that could be faulty, thus not redirecting hot/cold air properly? I have searched quite a few sites for info with no luck and I have a Hayes manual ordered (not much use to me yet), any help is appreciated. Thanks, Greg (Feeling hot in cold Newfoundland) >I have just purchased my first Saab two weeks ago, a 1990 9000 Turbo, I love >it already! [quoted text clipped - 7 lines] >manual ordered >(not much use to me yet), any help is appreciated. Did the previous owner say that the heater control valve itself was broken, or just that the heater core would continuously heat the air flowing through it and into the cabin of the car? When he 'bypassed' the core, what exactly did he do? Did he disconnect the two hoses from the ports on the back of the heater control valve (which poke through the firewall into the engine bay) and plug them or join them together? I just did a heater control valve replacement job on my 1985 900i and you're more than welcome to check out the web page covering it at "http://lios.apana.org.au/~c900/heatervalve.html" to see if that helps at all. With the one I replaced, the metal control shaft had broken off, so the valve itself is probably still ok (I haven't thrown it out - going to use it for a demo at a club meeting in the near future), but I don't think the shafts are available to buy on their own. Regards, Craig.  SignatureCraig's Saab C900 Page --> http://lios.apana.org.au/~c900 Sydney, NSW Australia Craig's Saab C900 Workshop -- For all Saab C900 Enthusiasts world-wide! http://www.saab900classic.net http://www.saab900.org c900@lios.apana.org.au Come and explore our site, and check out our web-forums, mailing list, etc. When he by-passed the core he diconnected the hoses at the heater core ports and joined them. I have reattached them since the weather here has been cold! I'll will take a look at the heater control valve tonight to see if it is functioning. Thanks for the response and the link to that web page, should be very helpful! Greg >>I have just purchased my first Saab two weeks ago, a 1990 9000 Turbo, I >>love [quoted text clipped - 35 lines] > > Craig. >>I have just purchased my first Saab two weeks ago, a 1990 9000 Turbo, I love >>it already! [quoted text clipped - 22 lines] > for a demo at a club meeting in the near future), but I don't think the > shafts are available to buy on their own. The heater principles on the 900 and the 900 are different. The 900 has a valve that changes the coolant flow into the heater core, the 9000 has constant cooolant flow through the core and the heater control changes the air flow. In this way it is easier to design an automatic air conditioning system as the regulation becomes faster (remember that the 900 only has Ac while the 9000 can have AC or ACC) Signatureth > The heater principles on the 900 and the 900 are different. The 900 has a > valve that changes the coolant flow into the heater core, the 9000 has > constant cooolant flow through the core and the heater control changes the > air flow. In this way it is easier to design an automatic air conditioning > system as the regulation becomes faster (remember that the 900 only has Ac > while the 9000 can have AC or ACC) Ah ha, and my 9000 does have ACC, so I have to find out what regulates the air flow and where this is located. Thanks Greg >>The heater principles on the 900 and the 900 are different. The 900 has a >>valve that changes the coolant flow into the heater core, the 9000 has [quoted text clipped - 5 lines] > Ah ha, and my 9000 does have ACC, so I have to find out what regulates > the air flow and where this is located. I looked in the functional description in my Saab workshop manual for a 1992 9000 (having the ACC2 system). Both the air mixing valve and the air distribution valve seem to be located in the centre of the panel, behind the central air outlet and below the sun sensor. Functionally the air mixing valve is located between the fan and the heater core but how to get there I have not found out. The air mixing valve iactually consists of two valves: the lower valve controlling the air flow to the heater core and the upper valve controlling the air flow from the core. After the air mixing valve comes the air distribution valve which has five positions: Defrost: 135 degrees angle Heat: 112,5 - 135 deg. (defrost and floor) Floor: 90 degrees Up-down: 57 - 72 deg. (panel and floor) Ventilation: 45 deg. (panel only) Note also that the air mixing valve should go to cold position if the ACC is put in OFF mode Signatureth The ACC actuates two servo motors to adjust flaps which controls the amount of heated air from the heater core and cooled air from the AC evaporator. I take you mean flaps when you refer them as valves. > The ACC actuates two servo motors to adjust flaps which controls the > amount of heated air from the heater core and cooled air from the AC > evaporator. I take you mean flaps when you refer them as valves. OK, flaps maybe a better word (flaps control air flow, valves control fluid flow?) Signatureth >> The ACC actuates two servo motors to adjust flaps which controls the >> amount of heated air from the heater core and cooled air from the AC >> evaporator. I take you mean flaps when you refer them as valves. >> > OK, flaps maybe a better word (flaps control air flow, valves control > fluid flow?) ...except for *inside* the engine, in which case valves control the intake and exhaust flow. Oh, it's all so complicated, this language thing... ;-) -Fred W My guess is you have a leaking heater core. That is why the previous owner bypassed the heater core directing coolant flow from the pump side back to the engine. I'd reconnect the hoses back to their intended connections. If you small coolant or found the green stuff inside the cabin, that means the heater core has to be replaced. Replacing the heater core on a 9000 doesn't require special tools. But could be aggravating if you have never done it before. You remove the blower motor housing inside the aquarium and the heater core is right there looking at you. > Replacing the heater core on a 9000 >doesn't require special tools. But could be aggravating if you have >never done it before. You remove the blower motor housing inside the >aquarium and the heater core is right there looking at you. If replacing the core is what is needed, I can recommend the instructions here; http://saab9000.com/procedures/ventilation/blower/blower.html Can't fault them but don't underestimate how hard it is to get the blower assembly back in at the end (keep at it, it goes eventually). Also, if your 9000 is above 110,000 miles and you plan on keeping it for a long time you might want to consider changing the blower motor at the same time, they tend to start failing at that mileage although mine hung on until 145,000. Cheers, Andy SignatureAndrew Sinclair http://www.smellycat.org The key the removal and installation of the blower motor housing is realizing, after the connection to the rod controlling flap movement is disconnected, only two plastic snap locks are holding the housing in place near the bottom of the housing. If you give it enough room, you can wiggle it out. Brute force will just damage the plastic parts. Ask me how I know. >> Replacing the heater core on a 9000 >> doesn't require special tools. But could be aggravating if you have [quoted text clipped - 12 lines] > same time, they tend to start failing at that mileage although mine hung > on until 145,000. On my first 9000 the blower motor lasted 230000 km, on the second the blower is now at 130000 km and you may detect some unusual sound from it at low revs. Nothing disturbing yet and still less noisy than a 9-5 blower at its most noisy revs. Signatureth I don't think there is a heater control valve on a 1990 9000. Although made by SAAB, it is very different from c900. If the 1990 9000 is similar to later model year 9000's, colant flow through the heater core continuously. Control is provided by the ACC actuating a motor to close or open a flap. |
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