Longtime MVS Contributor Jason adds his input on changing heater core pipes on Volvo 850 cars. He also provides an aggregated list of heater core replacement forum threads.
jreed » After reading here about the good chance of having a leaking heater core and especially about suddenly bursting heater hoses, I decided it would be a good idea to do some preventative maintenance. So I replaced the heater core, heater core pipes and heater hoses which were all original on my 1997 855 GLT at 177K miles. Many others have already written up good descriptions and advice about how to do these jobs and which parts to use including:
- Song Huang: 98 V70 T5 Replacing the Coolant Hoses in Pics
- Ben850: 1996 850 Turbo Wagon White
- cn90: 1998 S70 GLT Trans Cooler Line Rebuild for $10!
- rspi: Heater core replacement S70, V70, XC70, 850, C70, P80
- Matthew1: 850 Heater core replacement
- Precopster: Volvo 850 heater core replacement 2
I wanted to add detail on how to get the gas pedal out of the way when removing and installing the metal pipes to the heater core. To me there just wasn’t enough room between the pedal and the white plastic AC duct to allow removal of the coupler:
Heater pipe
Use a pry bar to pry the head on the pedal hinge pin to the left:Heater pipe
Pry pin out about 1cm:Heater pipe
When it is out far enough, the copper leaf spring will push the whole pedal assembly upwards:Heater pipe
Move the pedal assembly to the side. There should now be enough room to pull the coupler out of the foam ‘socket’ it is pressed into (be sure the two T25 screws in the engine compartment have already been removed):
Heater pipe
After removing coupler from firewall:
Heater pipe
I found that getting the old coupler out was a lot harder than getting the new one to go back in.
When I was inspecting the old heater core, I found signs of leakage with the biggest being right above the inlet and outlet ports where the aluminum tubes enter into the plastic end caps. There was some green residue visible. I hadn’t noticed any drips, or the smell of coolant, or a filmy residue on the inside of the windshield or detected a significant loss of coolant at the reservoir (maybe 100mL-200mL every couple of months).Leaking core
The green residue on the core at higher magnification. It looked like some kind of geologic formation you’d see inside of a cave:Jupiter, or Leaking core magnified closeup
The other suggestion I wanted to make was to recommend a pair of hose pliers for removing the old heater hoses from their connections to the engine. I had a nice pair that I got for Christmas this year that worked really well to grip the hose and let me twist it to break the bond and pull it off the fitting.
Hose pliers
