Just purchased a 1996 Volvo 850. Heating and cooling system seems to be out of whack. When windshield fogs and you try to turn on defroster, steam blows onto the windshield making it worse than before. This problem seems to be worse on the passenger side. Have topped up freon in a/c with sealant as well. I have to carry a cloth in the car to wipe the interior windshield. There is a faint chemical smell in the steam.

Any suggestions as to problem/solution would be most appreciated.

 

Need a new heater core.

 

Yep, new heater core. You're actually blowing coolant out the vents. Hence the "faint chemical smell". You can pick one up from FCP Groton or off ebay or vandsautodismantlers.com.

 

Thank you so much for the speedy and knowledgeable responses! We were wondering if this could be as simple as replacing the o-rings? Is a heater core replacement going to be "major surgery"? Is it done by disassembling the dash? We can't find a haynes/chilton manual for this model but are dedicated do-it-yourselfers. I have checked the online resources jks2 suggested and have found the heater core for a reasonable price through V&S Auto Disassemblers. Thanks so much for that info and I would appreciate more if somebody doesn't mind giving it.

 

Heater cores aren't too difficult on these cars- they come out the bottom of the middle part of the dash. And if the core from "V&S Auto Disassemblers" is a used one... don't get it. Used heater cores are a false economy, as the heater cores are prone to leaking on these cars, and a used one is liable to go belly up real quick. Alldatadiy is a great source for repair information... it's like a chilton's on steroids, with the actual factory information. I'm pretty sure there's a guide on here somewhere as to how you do it... but basically, you remove the trim panels on the sides of the console, directly where they butt up against the firewall, then there's about 4-6 (can't remember how many) torx bolts holding the heater core in place. Make sure to use new o- rings!

 

+1 on heater core....

http://www.fcpgroton.com/product-exe...50+Heater+Core


The procedure:
http://www.volvospeed.com/vs_forum/i...-core-install/

About a 1-2 hour job for an experienced tech; double that for a novice...

 

Probably not the o-rings since the o-rings are on the outside of the air flow. If you were leaking there it would smell but you would not have the fog issue. I support heater core, and buy a new one.
They are very easy to replace.

 

Thank you to all.

 

Do yourself a big favor and buy the Behr heater core see this thread

https://volvoforums.com/forum/general-volvo-chat-5/heartbreak-aftermarket-counterfit-parts-39807/

 

Had the same problem with my 93 850. Replaced the heater core -- no more foggy windshield. Very easy to replace too... took about an hour and a half to replace the core, junction and o-rings. Just as a not though, make sure you have plenty of rags or w/e u want to use to absorb the coolant that will pour out of the old heater core. Mine made a mess all over the carpet... guess i didn't have enough rags