Tutorial: Replace the heater core on a 1993-2000 Volvo 850, S70, V70, C70 and XC70
This post should apply to all 850s and first generation 850, S70, V70, C70 and XC70 Volvos. I chose to go with showing how the heater coupling is replaced in addition to the heater core as when I attempted to replace JUST the heater core I had leaking in the cockpit. This may have been in part my badly rusted IRON heater pipes, which I replaced with the newer aluminium ones from V70/later 850. As the inner seal kit is not available the only choice is to replace the entire coupling.
“I fitted my new heater core today. When putting it back together I had trouble mating the coupling with the plate in the firewall with nothing behind the coupling to keep it in place. I also dented the fins on the core in one spot getting it back into it’s casing. I hope this doesn’t cause any problems. I notice in the pics above on the 850 you seemed to have plenty of room to undo those screws in the engine bay. I had a round disc shaped item in the way & wasn’t game to undo it. I managed but it took a while & a bit of skin off the knuckles lol. I got it all back together & started it up to check for leaks. First thing was – yes – I had warm air. Then, right at the point where the pipes enter the core – slow drip, even though I had cleaned up & put new O rings on the end. So I undid the casing, gently pulled the core down and pulled it sideways as best I could because it appeared to be leaking from the least accesible torx screw on the yoke that the pipes run through. I had unscrewed them before realising I didn’t need to. I tightened all the screws again & got it back together. Ran for 5 mins with no leaks. I turned off the engine & started to pack up. Just before I put the kick panel back on I had another quick look. It had dripped, oh (%$#&^%). I think it’s a VERY slow drip. It might even seal completely when everything is up to operating temp. I don’t have time to go in again for a few days, so I hope it’s slow enough not to cause concern. I drove the car about 5 K’s & can’t smell any coolant. I’ll be keeping a close eye on the water level until I can go in again…”
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Thanks to Tailor we now have a write up with the swapping of a ’97 850 into a ’94. The ’97 has SIPS while the ’94 doesn’t so this is especially interesting and may benefit those with worn out early 850 seats when they can only find later model 850 seats for a replacement.