Step 4: Confirmation of diagnosis

Confirm that core has a leak. This old core leaked (very slowly) just under atmospheric pressure after I filled it with water. Or you can flush with clean water, clean the pipe holes, fill with water, put your thumb over one hole and blow hard into the other hole hoping to confirm a leak.

Assuming you have found a faulty core, get yourself a new one:
Volvo 9144221 Heater Core/matrix/radiator (an OEM part costs circa US$150 or £100). Order new o-rings while you are at it.

Ft the new core into the white plastic using those four torx screws, and the o-rings on the pipe stubs.

I didn't check my o-rings and all was OK, but if for some reason they went missing or were damaged you would find that your system could leak at this joint. Don't take this risk.

Great write up, photos and annotations!<br>It certainly helped give me confidence to tackle the job. Was able to do it in an hour, knowing exactly what to look for at each step thanks to this. So, many thanks!
hi, <br>thanks for the feed back. <br> <br>actually i did this bypass operation, and run with the 2 hoses bridged for more than a year. no heating at all of course but i where confident about keeping the coolant at its workplace. <br>i got a new core one month ago and now is working perfect again. <br>Volvo 850 SW TDI with 390.000 km <br>For me, the best car ever (for under 1500&euro;) <br> <br>thanks! <br>
<p>I have a Volvo 850 &quot;love it&quot;. I also did this bypass, a year ago, did fine , no heat though, i had it rough during winter, could not get windscreen to clear. However now after a year, a problem has develped. The car overheats especially on prolonged idling, lke in traffic jams. Temp. shoots up, and hot steam, and coolant starts spewing from the reservoir plstic or expansion tank. The cooling fan at the radiator never comes on, even when the car overheats, I changed the thermostat no change. give an answer if you can at, frankkazibwe@yahoo.com</p><p>Frank</p>
great instructable!<br><br>specially because you point out the screw that i was missing, the one inbetween the 2 pipes!!!! thanks so much<br><br>just one question:<br>lets imagine that i have no core replacement for a while and mine is broken with a big hole in the bottom (it exploded while cruising at the higway, with a huge steam flood, scary) but i am in the road and need to continue...<br>can i just bypass the core with a piece of hose connecting the 2 pipes?<br>i will loose heating but i will keep the coolant in his place (da engine), right?<br>will it interfere with any other thing?<br><br>good job
You could just put your temperature controls all the way to cold, that would prevent coolant from traveling through the heater core. <br> <br>Your idea of connecting the 2 pipes would work, but I really doubt you would be able to feel much, if any, heat at all.
Sorry that my expertise/memory doesn't stretch to giving you a reliable answer on this ... can anyone else here help lobo0x7?<br><br>Dom
Thanks for the great post. I have been needing to do some <a href="http://www.wightmanmechanical.com" rel="nofollow">heating repair in Kelowna</a>. I really appreciate the tips here.
Thanks for this man. I didn't even imagine that anyone had done this, i only just Googled in curiosity since i got so far and didn't know what to do next. Too bad, too, because i've got the entire dashboard superstructure out in the driveway.<br> <br> :O<br> <br> Oh well it needed work anyway cause it rattles a lot, and the stereo was hooked up wrong. And i learned a lot about how all that mysterious stuff works back there.<br> <br> Anyway many thanks, and i'll pay it forward next time i fix something i know how to fix i'll be sure to document and Instructable it.
One more tip, clean the heater core of the packing oil. It took a few days with the windows down to burn off all the oil. Thanks for the instructions it was very easy I did it on my lunch break at work.
I recieved a &quot;Heater Pip line&quot; part from the volvo dealership they told me this was one of the pieces that needed to be replaced on my 97 850 turbo 2.4 along with the &quot;heater hose&quot; itself. Are these the right parts?
Sorry, I can't help you with that ... I'm not a pro, I no longer have the Volvo 850 ... you might be able to tell from my pics whether that's a component of the system (it looks familiar). GOOD LUCK!
Yesterday I was treated to a warm foot bath on the way to work. I thought this was the death of my 95 850 with 260,000 miles on it. Thanks to your instructable it will live to die sometime in the middle of winter, in a blizzard or nor'easter.
Only 260,000 miles? I don't think this will be her last winter!
Very Help full,I replaced my heater core in my 1999 V70 with one I bought on line at a auction site for $40,it was brand new and came with Orings and Foam Tape. your instructions were great! .trash bag was KEY to keep from flooding my cars carpet.<br>Thank You VOLVO FOR LIFE!
I'm glad it was useful. :)
Good instructable.&nbsp; Yours looks a bit more accessible.&nbsp; I did some heater/blower work a few times on&nbsp;my 244 and it was a nightmare.

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