coolant leak, seems to be heater core supply line

mrscullini · Post by **mrscullini** » 30 Nov 2010, 22:01

2000 v70xc se with 145k

i've developed a coolant leak. it seems to be coming from the heater core supply hose. the suspect hose exits the block on the driver's side and goes directly to the fire wall. it seems to be leaking from the underside of this hose. is this a common failure?

i found this post which is similar to my leak,

https://www.matthewsvolvosite.com/forums ... =1&t=30400

however, i don't think it is the water pump as the pump is on the other side (passenger's side) of the motor. any insight?

if it is this hose, it seems to be a royal pita to replace, any comments?

Post by **Ozark Lee** » 30 Nov 2010, 22:37

Usually the heater core itself blows up before the lines / seals crap out but your problem is not totally uncommon. Everyone that has replaced a heater core has encountered your problem with the seals.

My suggestion is to buy a complete seal kit before you even start to mess with things so that you have all of the parts there to get on the road in the morning.

It is a double deal and there are multiple O-rings and spacers involved - don't try to match OEM and aftermarket parts in the same installation - that won't work.

...Lee

mrscullini · Post by **mrscullini** » 30 Nov 2010, 22:47

thanks lee, but you lost me. i replaced the heater core many miles ago. my issue is in the engine compartment. it seems to be a hose, no seals. am i missing something.

Post by **jblackburn** » 30 Nov 2010, 23:52

I've blown up the heater hoses on every other car I've owned. It's a common problem, and the hoses in these things aren't the best after 10+ years, my car is testament to that fact. My heater hoses are the ONLY rubber hoses still in the car that haven't let go yet.

The bad news is that they are expensive, and I wouldn't go aftermarket for them. I have seen (and had) cheap hoses blow up under pressure within a short time span of replacing them. The hoses attach to a hard to get to place on the engine (it may be darn near impossible to reach from the bottom on an AWD model; I'm not sure), and then there is a quick-connect fitting at the firewall that junctions into the heater core box. Purchase new O-rings for that fitting when you get the hose.

mrscullini · Post by **mrscullini** » 01 Dec 2010, 06:14

jablackburn wrote:I've blown up the heater hoses on every other car I've owned. It's a common problem, and the hoses in these things aren't the best after 10+ years, my car is testament to that fact. My heater hoses are the ONLY rubber hoses still in the car that haven't let go yet.

The bad news is that they are expensive, and I wouldn't go aftermarket for them. I have seen (and had) cheap hoses blow up under pressure within a short time span of replacing them. The hoses attach to a hard to get to place on the engine (it may be darn near impossible to reach from the bottom on an AWD model; I'm not sure), and then there is a quick-connect fitting at the firewall that junctions into the heater core box. Purchase new O-rings for that fitting when you get the hose.

thanks, this is what i kinda figured. it will be impossible to reach from the bottom. from the top, it will just take the removal of a lot of components to have full access. i'm thinking i should probably replace both hoses while i'm in there. the one hose attached at the side of the motor. where does the second hose attach? it seem to be at the back of the motor, near the turbo.

Post by **jblackburn** » 01 Dec 2010, 08:07

where does the second hose attach? it seem to be at the back of the motor, near the turbo.

Might be; I honestly don't know. There are several metal coolant lines in the back of the engine bay there, so it may attach to one of those. While you're at it, have a close look at the rubber parts on those lines - from the expansion tank over to the inlet hose into the turbo. Mine were swelled up, and the one at the turbo itself was leaking. These were visible from under the car and fixable from the top after removing some stuff; I've never been under an AWD model so I can't say what you can/can't see from under one.

jnormandeau · Post by **jnormandeau** » 14 Feb 2011, 08:25

Hi

How did this repair go? I have the exact same problem now. I can see it leaking from the supply lines when I run my heater and crawl under my car.
I cannot tell if it is the hoses or the seals going into the engine./heater core/exchanger....
Looking at some repair tickets from the previous owner, the heat exchanger was replaced 25K miles ago but it looks like they did not replace the hoses...

Any incite on how you tackled replacing the hoses/seals would be helpful.

Cheers,

Jim

1990 V70GLT

mrscullini · Post by **mrscullini** » 15 Feb 2011, 14:05

jnormandeau wrote:Hi

How did this repair go? I have the exact same problem now. I can see it leaking from the supply lines when I run my heater and crawl under my car.
I cannot tell if it is the hoses or the seals going into the engine./heater core/exchanger....
Looking at some repair tickets from the previous owner, the heat exchanger was replaced 25K miles ago but it looks like they did not replace the hoses...

Any incite on how you tackled replacing the hoses/seals would be helpful.

Cheers,

Jim

1990 V70GLT

hi jim.
haven't done the repair yet. my leak was right at the end of the hose which connects to the block. i was able to remove the hose and cut of an inch or so to remove the leaking part. obviously, this is just a bandaid. my estimate is that it will take approximately 3 hours. you will have to remove quite a few things but this should give complete access. while i have the system drained, i am gonna replace all the cooling lines.

jnormandeau · Post by **jnormandeau** » 16 Feb 2011, 08:08

OK, thanks for the info. 3 hours of tearing apart air lines hoses isn't too bad... better to pay me to do it than a shop.....

I realize now that there are no seals for the connection to the engine block but rather a hose clamp.......

Cheers,

Jim

1999 V70GLT

Post by **xHeart** » 28 Feb 2012, 11:29

Thank you for this discussion.
Has there been a repair/replacement update since?

The climate control is troubling this winter. A crack appeared on dash few weeks ago one frigid morning after turning the heater ON, a loud pop.

: A crack on dash above the center console; CrackedDash_Gap.jpg (352.71 KiB) Viewed 5976 times

This morning, the low coolant warning light came ON while driving to work. The expansion tank is empty at this time. Thinking of towing, more later...