I developed a leak in my coolant system, but wasn't finding any coolant dripping in the engine compartment, so determined it was in the interior of the car with the heater core. I pulled my heater core, but it didn't have any corrosion and when filled with water, doesn't seem to be leaking.
In reading another post about the heater core on another forum (http://groups.google.com/group/alt.a...a57127c6d14a15), the author mentions that pulling the heater core may or may not discharge the A/C system.
I recharged my a/c the day the coolant leak began happening. My question: are the heater core and the a/c system connected? If so, is there some other place the coolant could be leaking that is not the heater core? I'm wondering if I need to replace the heater core, or if I should be addressing the leak someplace else.
Any/all help is much appreciated.

1995 850 turbo station wagon
162,000 miles

 

Greetings,

>My question: are the heater core and the a/c system connected?
No, the heater core & a/c evaporator are separate unit and there is no physical connection between them.

The best method to find the leak is to pressure-test the cooling system. Or, you can do this by idling at park for 10-20 minutes, which is rather a waste of fuel but puts stress in the cooling system.

Some possibilities I know of:

1. Faulty reservoir cap, allowing vaporised coolant to escape.
2. Faulty reservoir itself.
3. Slow water pump seepage.
4. Radiator, where the aluminum & resin parts meet (on the sides of the radiator).
5. Faultyhead gasket, allowing coolant to seep into the combustion chamber. Should be noticed by white smoke & coolant odor from the tail pipe.
6. Radiator/heater hose connections.

How fast is the coolant level dropping? If noticeable within a day, there should be a visible sign but if not, the leak may be small and may not go detected by visual inspection.

Again, try having it pressure-tested at a reputable shop.

Good luck,


JPN

 

Thanks for the reply. The leak is definitely somewhere on the interior, as the coolant is dampening the rug. I think it's just a very small leak in the heater core. I think I'm going to go ahead and replace it, see if that will fix the problem.

1995 850 turbo station wagon
162,000 miles

 

Hello again,

You're right, it does seem the heater core; it may have a hairline crack and the leak may only appear under pressure. I cannot remember if the heater hose connection was in the engine compartment or behind the firewall, but the connection may be suspicious as well.

At FCP Groton, there are two parts for the suspicious unit:
http://www.fcpgroton.com/volvo850cooling.htm

There is a unit called "heater plugger", which seems to connect the heater hoses to the heater core. Did you check this item? I'll attach pics. I usually buy parts from Groton because I never used eBay and don't feel comfortable using it.

Good luck,


JPN

1. Heater core (Nissens-Behr: Behr is German but not sure about Nissens, sounds like Japanese): $128
2. Heater plugger: $36
3. Heater core O-ring kit: $7.50


[IMG]local://upfiles/6892/B6AF17297E784B4EB44FF1E03BAB2067.jpg[/IMG]

[IMG]local://upfiles/6892/DDDEFA4A6440436083DA3474D1BBEC11.jpg[/IMG]

[IMG]local://upfiles/6892/0E0A9A9180F24D0691738486E6904E3D.jpg[/IMG]