Heater Core Replacement

1997V90BGG · Post by **1997V90BGG** » 12 Dec 2015, 11:52

Hey All, Greeetings and Happy Holidays. I have a 1997 V90 Wagon and the heater core needs to be replaced. I'm confident I can do the job myself I just need some help. I've reviewed the replacement videos for S70's and under the dash looks nothing like I see in the videos. Does anybody have a schematic or site where I can find more information? I noticed there's a plate on the fire wall that almost looks like you could remove the core from the engine compartment. Is that true? When I pulled the knee bolsters off I see a lot more components then on the videos and can't even see where the heater core might be.

Suggestions, Comments?

P.S. I've used the site before but had to re-register as I forgot or misplaced my login info. You all have been very helpful in the past.

93Regina · Post by **93Regina** » 12 Dec 2015, 14:12

"NOTE: On vehicles equipped with Automatic Climate Control (ACC), a thermal switch is located on the outlet hose from the heater core. It switches on and starts the fan motor only when the water temperature exceeds approximately 95°F (35°C). This prevents cold air from being blown into the passenger compartment during winter. The thermal switch is bypassed in the defrost position."

lummert · Post by **lummert** » 12 Dec 2015, 15:56

Just curious. Where would this switch be located on a 1988 760? Or does my 760 even have this switch?

lummert · Post by **lummert** » 12 Dec 2015, 15:58

1997V90BGG wrote:Hey All, Greeetings and Happy Holidays. I have a 1997 V90 Wagon and the heater core needs to be replaced. I'm confident I can do the job myself I just need some help. I've reviewed the replacement videos for S70's and under the dash looks nothing like I see in the videos. Does anybody have a schematic or site where I can find more information? I noticed there's a plate on the fire wall that almost looks like you could remove the core from the engine compartment. Is that true? When I pulled the knee bolsters off I see a lot more components then on the videos and can't even see where the heater core might be.

Suggestions, Comments?

P.S. I've used the site before but had to re-register as I forgot or misplaced my login info. You all have been very helpful in the past.

Maybe searching for info on a 960 would get better results than a S70.

Post by **xHeart** » 12 Dec 2015, 21:05

This may help a little. Heat exchanger is # 8

93Regina · Post by **93Regina** » 12 Dec 2015, 22:17

lummert wrote:Where would this switch be located on a 1988 760?

I got that from an online "manual," which is not a good reference source. Vehicle would have to have "Automatic Climate Control (ACC)"

Volvo states: Automatic climate control - The Auto function automatically controls temperature, air conditioning, blower speed, recirculation and air distribution.

So, does your 1988 have " Automatic climate control"

93Regina · Post by **93Regina** » 12 Dec 2015, 22:23

lummert wrote:Just curious.

Here's some documents, related to OP's vehicle, and apparently yours.

93Regina · Post by **93Regina** » 12 Dec 2015, 22:26

1997V90BGG wrote:I have a 1997 V90 Wagon and the heater core needs to be replaced.

See this thread, mainly post four

lummert · Post by **lummert** » 13 Dec 2015, 11:00

93Regina wrote:
lummert wrote:Where would this switch be located on a 1988 760?
I got that from an online "manual," which is not a good reference source. Vehicle would have to have "Automatic Climate Control (ACC)"

Volvo states: Automatic climate control - The Auto function automatically controls temperature, air conditioning, blower speed, recirculation and air distribution.

So, does your 1988 have " Automatic climate control"

Thanks for your info. My 1988 760 has ECC, maybe the first year for ECC. My fan sometimes (possibly most of the time) starts so slow that it sometimes throws the ECC into fault. Diagnosis says it's the heater motor even though I've tried 4 different heater motors with the same result.

93Regina · Post by **93Regina** » 13 Dec 2015, 11:55

lummert wrote:My fan sometimes (possibly most of the time) starts so slow...

I've never explored this topic, but if there is a relay(s) for fan speeds, I'd replace it (them), and make sure whatever supplies power to these relays is good. If a "master relay" powers these relays, it too should be replaced.

Hence, check specs for fan's current draw, and then check current draw...if full fan amps are not there, you have a current issue.

Also, check fan current when directly hooked to battery terminals, with engine running.