Coolant leaking from heater core.

02V70 · Post by **02V70** » 05 Apr 2022, 17:12

Coolant is leaking quite a bit from where these pipes meet the heater core.

: DSC01014.JPG (1.74 MiB) Viewed 2706 times

How would I fix this? Does the heater core need to be replaced? What If I just slather a bunch of rtv on it?

Post by **firstv70volvo** » 05 Apr 2022, 17:25

02V70 wrote: ↑05 Apr 2022, 17:12 Coolant is leaking quite a bit from where these pipes meet the heater core.

DSC01014.JPG

How would I fix this? Does the heater core need to be replaced? What If I just slather a bunch of rtv on it?

Likely the o-rings, it's a fairly common problem as the o-rings harden with age. Replace with OEM parts, the o-rings and retaining clips. It's not a fun job working under the dash but at least it's an inexpensive repair. It's possible it could be the heater core but much more probable it's just the two o-rings.

02V70 · Post by **02V70** » 05 Apr 2022, 17:45

I found the o-ring and retaining clips on fcp Euro. For the O-rings, they have OEM, and Geunuine Volvo. Since the OEM ones are 10x cheaper than the Genuine ones, is it fine if I get the OEM ones?

Post by **cn90** » 05 Apr 2022, 17:51

- Time to replace the heater core itself, if you have the budget...
- I use only genuine Volvo O-rings.

- I wrote the DIY for my 2005 XC90 in the XC90 section...

Post by **chrism** » 05 Apr 2022, 19:04

When I replaced the heater core in our (now gone) 2005 S80 I re-used the original retaining clips as they appeared to be better quality/better fit than the clips provided with the new heater core.

As a side note, I replaced the original leaky core with a no-name unit from the local auto parts store. About a year later it started leaking. Ended up replacing it again with a Behr unit which I believe was OE.

Post by **cn90** » 05 Apr 2022, 19:23

1+,

- Metal clips should be re-used.
- O-rings: Volvo genuine only, it is not that expensive.
- IIRC, the Behr heater core was made in France...

https://www.matthewsvolvosite.com/forum ... hp?t=82726

02V70 · Post by **02V70** » 05 Apr 2022, 21:10

I also got the Volvo genuine hose clips as the many reviews for the product stated that they bent the original ones taking them out. When I do change the o-rings, how much coolant needs to be drained, and where do I drain it from?

Post by **cn90** » 05 Apr 2022, 21:24

@02V70,

Did you try to click on the link I posted above?

02V70 · Post by **02V70** » 05 Apr 2022, 21:46

Yes. It will be a very helpfull tutorial, thank you.

You did not mention draining the coolant, you only said to put a plastic bad underneath to catch some spilled coolant. So do I not have to drain anything?

Post by **cn90** » 05 Apr 2022, 22:26

No need to drain radiator or cooling system.
Just replace what is lost during the job.
Not much loss, maybe 1/4 gallon...