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Heater: Core or Blower ?

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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Xcountryer
Posts: 8
Joined: 19 November 2010
Year and Model: 1998 V70 XC
Location: Northeast

Heater: Core or Blower ?

Post by Xcountryer »

Have a 1998 V70 XC. Blower not working at all (it has been cold brothers and sisters) and smell a little coolant. So I see that I can replace the heater cores but how do I know if it is not the heater core but the blower engine itself ?

Temp is accurate. Blower not on at all - i.e. if I turn it on, nothing happens.
Blower fuse ok and I have plenty of coolant.

Last, if it is the core, can I just replace the driver side ? Not both ?

THX :roll:

JRL
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Joined: 22 November 2005
Year and Model: Several
Location: 19333
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Post by JRL »

Probably both
A bad heater core has nothing to do with the blower not coming on.

You will probably need;
Heater Core (+0 rings)
Blower Motor
Resistor pack

However, before you buy everything you should have it all diagnosed
Mod note. Jim passed away in early 2022, his contributions to this forum are immortal, and he is missed. RIP

2000 V70R Black, 144,000 miles Wife's R.
2007 V70 2.5T White/Oak 111,000 MILES. Polestar tune, IPD bars, rear spoiler, dark grey Thors, DWS 06, HU850, sub.

Xcountryer
Posts: 8
Joined: 19 November 2010
Year and Model: 1998 V70 XC
Location: Northeast

Post by Xcountryer »

Thx.

Dealer will tell me both are needed, for sure. Will just core give me more heat ?

Anyone with any non dealer Fairfield Cty, CT independent Volvo mechanics, please let me know.

mdempst_79
Posts: 50
Joined: 18 October 2008
Year and Model: 2006,2007 XC90
Location: Durham / Ontario,Canada

Post by mdempst_79 »

Heater core may not be bad, maybe just the o-rings.

If you remove panels from center console behind carpet right beside accelerator pedal (black plastic panels) you will be able to see two aluminum lines that go from firewall to the bottom of the heater core. These pipes have o-rings on either end... Now these will leak if touched / moved around / looked at too long, at least in my experience.. so you may only need the o-ring kit. You will also be able to see if there is coolant dripping out of the bottom of the heater box.

The Blower motor can be tested by removing glovebox and checking resistance of motor / prescence of voltage at motor connector. You could also just take it right out and hook upto a 12vdc power supply to see if it turns, just make sure to hold it tight so it doesnt take off!.

Usually you will see the lights flashing on the heater control unit if it detects a problem (if you have the auto climate control). These codes can be looked up on the board here... Or scanned through the OBD port

Good luck, hopefully you get an idea before you head to the dealer!
2007 XC90 V8 Sport 265,000km
1994 850 Turbo Auto 365,000km (R.I.P - 2005-2017)
2006 Ford F350 Super Duty 4x4 Diesel
1999 Landrover Discovery II 259,000km
1992 Range Rover Classic 3.9 250,000km (In restoration)

vjaneczko
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Year and Model: 2006 S60R
Location: San Antonio, TX
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Post by vjaneczko »

There's only one heater core, not two. It's mounted just below and behind the radio. You can pull up the carpet on the drivers side, remove the side panel on the center console and you'll see it. Check for any leaks or fluid on the floor. It's real easy to swap out - if you have a heated garage, it'll be real easy!

If the blower motor is not working, you will feel some heat as you drive, just from the force of air getting pushed through the system. Installing a new core will not increase the amount of heat you get from the system.

The blower motor may have seized, which puts a big load on the resistor (or power stage, if you have the ECC) and will blow it. You may have to replace both items. Plenty of posts on swapping them out. I'd first check the blower motor itself. If you can easily spin it by hand, it's probably good.

One other thing to do is check for the cabin air filter, which is accessed under the hood in front of the passenger side. Volvo didn't install them in a lot of cars which causes bits to fall into the motor and cause premature damage.

You "could" hit the dealer for a diagnostic, but it's a real no-brainer to check yourself, so save your cash. This site helped me swap this stuff - and a lot more!
Last edited by vjaneczko on 27 Jan 2011, 11:19, edited 1 time in total.
"He attacked everything in life with a mix of extraordinary genius and naive incompetence, and it was often difficult to tell which was which." - Douglas Adams

1997 855 GLT - R.I.P.
2006 S60R - For ME!

Xcountryer
Posts: 8
Joined: 19 November 2010
Year and Model: 1998 V70 XC
Location: Northeast

Post by Xcountryer »

Perfect. Thx all !!!!

JRL
Posts: 9350
Joined: 22 November 2005
Year and Model: Several
Location: 19333
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Post by JRL »

Blower is accessed by removing the lower dash
The glovebox does NOT have to be removed
Mod note. Jim passed away in early 2022, his contributions to this forum are immortal, and he is missed. RIP

2000 V70R Black, 144,000 miles Wife's R.
2007 V70 2.5T White/Oak 111,000 MILES. Polestar tune, IPD bars, rear spoiler, dark grey Thors, DWS 06, HU850, sub.

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BEJinFbk
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Joined: 5 January 2008
Year and Model: '98 V70 R
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Post by BEJinFbk »

Pulling the glove box makes a huge difference.
MUCH easier reach - Here's a link for ya:

https://www.matthewsvolvosite.com/forums ... =1&t=19322
'98 V70 R - Well Equipped for Life Up North... ;)

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