Coolant on the carpet, from where?

[FireFox31]

My 2000 V70 with 250k miles has had coolant under the front driver's carpet for a while now. I'm not sure when it happened since my coolant level is at max. Suspecting a leak at the heater core, I pulled back the carpet and saw some old evidence of leakage. I observed no leaks while idling the engine up to temp for about 10 mins while changing the heat and vent settings.

Under the first layer of carpet was slightly damp. The mass of coolant was soaked into the rubberized foam beneath the carpet, oozing up through cracks in the rubber. I've got to remove both the carpet and rubberized foam to clean this up.

A few questions about this:
Could the coolant come from something other than the heater core?
Should I remove my heater core and inspect it for leaks?
To remove the front driver's carpet, do I have to unbolt the front seat's rail front bolts?
Are there any tricks to removing the black rubberized foam beneath the front carpet?
How can I clean coolant out of the carpet and foam?

This post shows possible leaking on a 25k mile core, and others said they replaced the cores around 150k miles. But here I am at 250k miles with the original core. Should I just swap it? Thanks.

[dorvin]

If you're sure that's the original heater core, I would replace it for peace of mind, if you're already going to pull it out to inspect it. From what I've seen, at 250k, you're already riding on borrowed time. Depending on where you park your car, it'll be a lot easier to replace it now before winter really sets in.

[tryingbe]

Heatercore.

[abscate]

The heater settings have no impact on the core - its full flow. If its a small leak, it will leak less when the car is cold and cooling system pressure is low.

There isn't anywhere else in the car where there is coolant, but 'core leak' here includes core, attachment point, hoses, tubes, or rings - quite a lot of places where the coolant can seep in the climate system.

At 250k original - I would replace it and all the cooling group hoses

[MrAl]

Hi,

Years ago i had a core leak in my Hyundai. I took out the core and found out i could not solder it because it was part aluminum. It was a small leak though, leaking maybe 1 ounce coolant per month if that. You could be sure it was the core though because it was slightly wet when examined. There was also a slight smell of coolant so i left one window open a little during any driving periods. I drove it that way for almost 20 years and the leak never increased.

With this car (Volvo) i have read that sometimes the core goes and floods the whole front floor. I hear they are made partly of plastic, which bites. I hope i dont have this problem in mine too. So far so good after the radiator change.

Another thing i have read is that coolant is corrosive so if left too long will eat up the floor. Perhaps there is some chemical that acts as a neutralizer that could be used to treat the floor if there is a leak, before a total cleanup can be done?

I was wondering though does anyone know if it is normal to loose a tiny amount of coolant, say over a period of one year, or is the system so well closed up that there cant even be a single drop of coolant lost in a perfect coolant system of the Volvo (like in a brand new Volvo) ?

[misha]

...I was wondering though does anyone know if it is normal to loose a tiny amount of coolant, say over a period of one year, or is the system so well closed up that there cant even be a single drop of coolant lost in a perfect coolant system of the Volvo (like in a brand new Volvo) ?

It's normal.Let's say from max to min between coolant change.It's not sealed closed.It have a breather cap.Some cars have a "relief" hose going from expansion tank and vented to atmosphere.

[abscate]

If you were topping up the reservoir with 250 ml of coolant every 3 months, that could be a leak too small to see or find without fancy equipment.

[scot850]

The favorite places I have had for small leaks are:

The smaller line that runs from the header tank to the top of the radiator on later cars and to the top of the thermostat housing on older ones. Check at both ends as it can get a really small weep.

Next one is the larger hose from the header tank either under the tank or where it connects to the metal pipe at the rear of the engine. Look for green color 'rust' at the join.

Third one was a new one. It was at the heater core. It was not the core, but the 2 'o' rings on the pipes to/from it.

Fourth would be the header tank itself may have a small crack. Lift it and look for damp under where it sits.

Lastly the relief cap could be failing. They do have a lifespan. I tend to use Volvo replacement as I have had issues with aftermarket versions.

Good luck!

Neil.

[MrAl]

...I was wondering though does anyone know if it is normal to loose a tiny amount of coolant, say over a period of one year, or is the system so well closed up that there cant even be a single drop of coolant lost in a perfect coolant system of the Volvo (like in a brand new Volvo) ?

It's normal.Let's say from max to min between coolant change.It's not sealed closed.It have a breather cap.Some cars have a "relief" hose going from expansion tank and vented to atmosphere.

Hi,

If it is not sealed then how does it build up pressure?

[jonnycycles]

I just fixed a leak in the same spot on my 2000 V70XC. With wet carpets and slowly dropping coolant level I was prepared to replace the heater core but instead tracked it down to simply a loose bolt: The torx head bolt that holds the hard pipes to the back the housing for the heater core. I tightened it up and no more leak.