1998 V70 heater hose leak at engine firewall

jgasn · Post by **jgasn** » 18 Apr 2014, 16:04

Hi, I replaced my heater core a couple of years ago but re-used the original firewall couplings. One of them has started to leak, have drops of coolant sprayed out over the rear of engine. No smell of coolant inside car. Is it possible to replace the couplings inside the engine bay without having to take out the hole heater core again.
It is a non-turbo and RHD so i have fairly straight forward access.

Post by **abscate** » 18 Apr 2014, 16:44

First just try to replace the O-rings on the seals..that might be all that are bad

You do need to work inside the car to remove the coupler but the heater core can stay in place.

Post by **erikv11** » 18 Apr 2014, 17:12

Not everyone feels the way I do about the coupler with it's many o-rings and temperamental connections, but my feeling is ... get rid of it, once the parts are old it is far more trouble than it is worth.

Here is a thread with some discussion and pointers:
https://www.matthewsvolvosite.com/forums ... =1&t=44948

Post by **precopster** » 18 Apr 2014, 17:53

My thoughts on the coupling are that if you're going to disturb it in any way then replace it. Aftermarket o ring kits for them have had a bad rap and cause leaks.

Also like all plastic and rubber composite components running 200 degree coolant through them they have a limited lifespan; just like firewall mounted plastic heater taps on the older 740s and 960s. Firewall couplers were designed to be removed easily and work very well when new.

Post by **cn90** » 18 Apr 2014, 19:39

I agree with erik.

Cut the metal pipes and run heater hoses from the metal pipes in the cabin ---> firewall ---> engine.
By doing this you will get rid of a lot of "middle men".

bugs11 · Post by **bugs11** » 21 Apr 2018, 15:07

I did the coupling bypass when I replaced my head gasket. Never could get the ancient fitting to stop leaking. No fittings, no leaking now.