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heater core? Posted by Arabiflora [Email]  (#1129) [Profile/Gallery]
(more from Arabiflora) on Wed, 10 Dec 2008 00:00:00
In Reply to: Frosty Window, Brian O'Shea, Mon, 8 Dec 2008 19:42:24 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I have a similar problem with my '88 900 except that it is the passenger side ports that blow cold air. The driver's side (DS) is toasty and warm but that is little comfort when the windshield won't fully defrost.
I can't help you with stereo removal but it may not be necessary-- if there is positive (even if cold) air flow out of the defroster baffles on dash and heater vents in and below dash, and that flow is properly controlled by the selector knob, you can reasonably conclude that your vacuum servos and ducting are in proper working order.
In my case, I dropped the knee bolster (lower dash) and shroud to reveal the heater core. Once up to running temp and dialed for full heat I felt the heater core itself. The right (passenger) side was stone cold, DS was almost too hot to touch. Since air flow through the core is driven by a centrally located fan at the back (firewall) side and ported to all vents by lateral DS and PS openings, all of the symtoms make sense-- air flowing over the PS of the core and distributed to the PS of the cabin is cold, DS air is warm.
So I pulled the core, flushed it out, hell I boiled it in a pot filled with radiator cleaner. Afterwords the water flowed through the in-tube and out the out-tube with zero resistance-- not that there was noticable resistance beforehand. Nonetheless, and thinking I had it licked, I reinstalled and retested with same results: PS cold, DS hot.
I've been stymied by this puzzle for quite a while since the symptoms would seem to be in violation of one or more Laws of Physics... until I happened upon a recent post (http://saabnet.com/tsn/bb/900/index.html?bID=379446). Karl writes
"A problem I had w/ my 99 heater core was that it seemed to have good flow, even the radiator man said so, but after installing it again, no heat. I re-pulled the core and ran hot water through it in the kitchen sink and only about two sections got warm so I took it back to the radiator shop and asked him to pull the tanks and rod out the core. He did and of course went on about how much crap he got out of there, but upon reinstallation I now have plenty of heat."
I had assumed that coolant flow through the core took a serpentine but non-branching course but have begun to reconsider that assumption. If the inflow coolant stream T's at one or more points it is conceivable that the vessel(s) that serve the PS portion of my heater core (DS on yours) are blocked, and having a shop 'rod out' the core could solve the problem.
But then there is the issue of inertia... The driver's seat and center console, and knee bolster will need to be removed; coolant lines to the heater valve will have to be disconnected and the shroud removed from the housing of the heater core. Disconnect core from the heater valve and take it to a shop to get 'rodded-out'. Reassemble.
Heat? Who needs it?!
My 2 cents (4 cents if you consider length but you get what you pay for), let us know how it works out for you.
Scott
, Mon, 8 Dec 2008 19:15:17, Wed, 10 Dec 2008 00:00:00 <-- Viewing This Message, Wed, 10 Dec 2008 23:24:15
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