Volvo 850 heater core replacement 2

volvogirl75 · Post by **volvogirl75** » 11 Aug 2012, 14:52

Every time I would drain radiator I would fill reservoir with fluids till it stayed level. As soon as I drove it overheated by boiling out. Reservoir. Then have to add more water or coolant. Just keeps boiling out. Even with just water.

Post by **MoVolvos** » 11 Aug 2012, 15:33

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Hi volvogirt75,

Let's go back to basics as things have side tracked a bit. Well, that said let's see if I can summarize this and get it right myself

!

First, you bypassed your heater core and it started to "Slightly" overheat - Air probably!

Then you replaced the Thermostat and it starts to overflow - Getting worse but now the car could have overheated and caused Head Gasket damage.

No Hole in the Thermostat - Overheating already and if the new one has no hole it is not helping with the initial diagnosis of Air

No oil in the coolant so far - Air and possible Head Gasket still?

Coolant in question 50/50 - You said no

Water Pump - A coincidence so not likely

Fan Relay - would be a coincidence like the water pump as the fan still is working

Should go back to the Air problem and Thermostat to rule those out before going down the Head Gasket, Water Pump or Fan Relay issues.

Blessings,
BKM
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Post by **rspi** » 12 Aug 2012, 03:50

VolvoGirl, please start a new thread and name it "Car is overheating" and you will get more readers and maybe the answer you need.

asedwards · Post by **asedwards** » 28 Aug 2012, 16:55

Thank you precopster. Your tutorial got me through the heater core replacement. No more fluid leaking into the floorboards.

javaqen · Post by **javaqen** » 15 Sep 2012, 17:15

After 6 months, finally convinced the hubby that because of the great directions and pics from this post that he really could fix this. And today he did, almost. Old heater core out, new one in, new o-rings, no initial leaks, heat came back we thought we were good to go. We let the car run a good 20-30 minutes saw that everything seemed to be okay and shut it off. That's when the trouble started. The (hot) water started gushing out from where the pipes connected to the core. There are clips there that were already on the pipes and still in good shape, so we left them. It appears the leak is coming from one of the pipes near where the clip is. We're missing something small and obvious here aren't we? If one of the clips didn't actually clip into place would that cause a leak? We also found a great video online but it didn't show removing the pipes at all which he did. Should we add more o-rings to that end of the pipe? Help - I'm SO tired of squishy floor mats and adding water EVERY day ...

Post by **precopster** » 16 Sep 2012, 04:29

Did the O rings come with the core?

If you purchased a Behr brand they usually don't come with the core and there aren't good quality O rings out there apart from the IPD red silicon variety or the OEM ones from the dealer.

I've used FCPs O rings which come with the core three times now and have had no problem. Have you tried retightening the torx screw at the heater pipe junction? There are no clips at the core, only a torx screw that clamps the pipe fixture into the core.

I don't know what you mean by clips that were already there.

If you read this whole thread most people haven't succeeded in having no leaks at the junction if they disconnected at the junction near the firewall. Only the ones who leave the pipes and clips alone and just undo the torx screw right at the core seem to be lucky.
That's why I suggested replacing the coupler junction with a new part as the aftermarket seal kits for the engine bay side available just don't work and as far as the cabin side they're not manufactured.

Hope this helps

Post by **Pauloil** » 16 Sep 2012, 07:21

javaqen wrote:After 6 months, finally convinced the hubby that because of the great directions and pics from this post that he really could fix this. And today he did, almost. Old heater core out, new one in, new o-rings, no initial leaks, heat came back we thought we were good to go. We let the car run a good 20-30 minutes saw that everything seemed to be okay and shut it off. That's when the trouble started. The (hot) water started gushing out from where the pipes connected to the core. There are clips there that were already on the pipes and still in good shape, so we left them. It appears the leak is coming from one of the pipes near where the clip is. We're missing something small and obvious here aren't we? If one of the clips didn't actually clip into place would that cause a leak? We also found a great video online but it didn't show removing the pipes at all which he did. Should we add more o-rings to that end of the pipe? Help - I'm SO tired of squishy floor mats and adding water EVERY day ...

you need to buy the junction box and replace it. I agree with what precopster said. the new box comes with all the o-rings you need up by the firewall. on the engine side of it, there is a thick plastic ring inside of the box that holds in the o-rings and spacers in. Pitch the thicker platic ring. taking off the gas pedal for more room makes it easier to get to the junction box, but be careful with cruise control and disconnect the link first. for right now while you are thinking about this, either cut the longer hose on the engine side to connect it to the other side and bypass the core. or you could pull both lines off the motor and just bypass the heater core with a new hose on the engine ports.

Post by **rspi** » 16 Sep 2012, 08:20

It's possible that he did not clip the pipes in the coupler all the way and just needs to push them in a little further. The other thing, as stated, the coupler is now cracked or broken and has to be replaced.

Post by **mtd240** » 12 Dec 2012, 09:27

I am getting ready to do a heater core on a '00 S70.

Parts list:
Behr (from FCP) Heater Core
Heater Pipes/Coupler (PN 9134978 from Tasca)
O-rings (PN 3545586 from Tasca - Part #9 in image from EEuroparts)

My only question is: What are the part numbers for the rubber heater hoses that run from the coupler to the block? The S70 has over 270,000 miles on it...and the driver is an extreme "don't fix till it's real-super broke" kind of person. I think it would be a good idea to go ahead and replace those..

Michael

Post by **cn90** » 12 Dec 2012, 09:34

Some suggestions:

1. Search forum but the Behr seems to leak in 1-2 years.
Many people are leaning toward this "Alvo Brand Heater Cores" on ebay for $40:
Take your time and read through this:
http://volvospeed.com/vs_forum/topic/15 ... ter-cores/

As of Dec 2012, there were already 400 "Alvo Brand Heater Cores" sold, so that speaks for itself!

2. Coupler blah blah blah. Search forum for post by "erikv11".
Basically cut the metal pipes (using a pipe cutter, $8 tool from hardware store) and run heater hoses (I.D. = 5/8", it is cheap @ $6 for 6-foot roll at local autoparts store) through the existing coupler.
Then seal air gap with some caulking.
This way you never have to deal with this coupler thingy again.

Volvo 850 heater core replacement 2

Re: Volvo 850 heater core replacement 2