Heater core replacement

s80joe · Post by **s80joe** » 03 Jan 2009, 22:17

I bought an ill fated 1999 S80 T6. Now it needs a new heater core. It is spewing coolant into the car on the floorboards. Being a home mechanic, I would like to do this repair myself. Is it feasible, or should I pony up and pay $800.00 to my mechanic to switch it out.Can anyone guide me to a book or website that would show me how to do this? Do I need special tools I'll never use again? How about a website to buy the heater core? Thanks for any help!

Post by **MadeInJapan** » 03 Jan 2009, 22:33

Welcome to MVS.
As far as I know I do not know of a write-up for this process in our repair database for your car or anywhere on the web (though there is a write-up for replacement of just the o-rings, prefaced in red below, so be sure and read that first). I've also been able to dig this up from VADIS for your car (scroll to the bottom of the pdf file...the actual section dealing with the heater exchange is very short and it doesn't look so difficult):

99 S80 Climate Control Replacement.pdf: (878.93 KiB) Downloaded 864 times

You should know that the pliers mentioned, you can buy at any auto parts store...basic locking hose clamps. You'll also need to know how to take the sound proofing panels out on the driver's side:

Sound Proofing Panels.pdf: (50.76 KiB) Downloaded 482 times

and possibly you'll have to remove the brake light switch according to the instructions (and apparently this is related to RTI in the steering wheel area but I don't see how). I am including that section from VADIS as well, just in case:

RTI Switches.pdf: (25.71 KiB) Downloaded 471 times

If you see a green link in the pdf files I've posted that you need, let me know. I can convert any of these to pdf.

Hope this helps and you get this taken care of without too much trouble.
-MIJ

Just found this to (don't start any repairs without reading this first): http://volvospeed.com/Repair/heater_core.html

P.S. Looks like you've got lots of extras on your cooling system from the first file above. Having a '99 S80 will be a challenge and this file may come in handy for you in the future.

anelson52 · Post by **anelson52** » 04 Jan 2009, 11:32

I had the same symptoms with my '00 S80, and it turned out to be just the O-rings. I used the volvospeed posting that MIJ pasted into his reply above, and it was a life saver (as well as a money saver)! I bought my O-rings from Autohausaz.com for about $3 a piece (you'll need 2) and was able to do the job in about an hour. Good Luck!!

Post by **MadeInJapan** » 04 Jan 2009, 14:12

Thanks for posting...great to have the confirmation about "only the 0-rings."

Pariah2001 · Post by **Pariah2001** » 13 Feb 2009, 07:50

I bought a 1995 Volvo 850 about 3 weeks ago from a family friend. I test drove it on the highway and it drove like a dream. It sat for the 3 weeks while I got the money up for insurance/plates/etc. I just started driving it this week, now the bottom of the windshield fogs up and there is a slight smell of antifreeze in the air, and the temperature gauge goes into the "warm" range (yes, I KNOW this is the heater core), but it slows down while I'm driving it after about 2-3 minutes. Sometimes I shift to a another gear to make it drive at a normal speed (it's not a manual...its automatic). Like I said, its been setting up for 3 weeks with no issues. Are the 2 issues related (are they know to be related in anyone else's models) or is it just a major coincidence that these things are happening out of the blue at the same time?

Post by **MadeInJapan** » 13 Feb 2009, 16:59

I doubt that they are related....
That said, this is the S80 section of the forum, so let me recommend you post over on the 850 section and see if you get some better responses...I personally suspect you may need a PNP switch and/or transmission flush.