'99 S70 Engine Temperature Indicator

[DePonce]

Well, with the cold weather no upon us, now I can smell the sweet odor of coolant when running the heater - However I can't not see any signs of leak near the heater core. Just cleaned the windshield looking for the obvious signs there....

[s70_Joe_Tx]

However I can't not see any signs of leak near the heater core....

The leak is sometimes so small, as to not actually leave wet spots. Coolant level may drop so slowly that the light doesn't come on for months. May find evidence under carpet or around drain.

On eBay, a seller claims to have an upgraded core and describes how the OE behr fails. Not to suggest core is legit or not, but might be interested read.

I have seen a lot of volvos for sale locally with "blown head gaskets". My assumption is many are misdiagnosed heater cores, or leaking heater cores and low coolant levels neglected for too long until the engine really did overheat and blow head gasket. They all certainly had low coolant lights on and smells from the heater. http://ebay.com/itm/360771830251?cmd=VIDESC

Definitely perform coolant pressure test after repairs. Basic tool is available for free loaner but volvo adapter will need to be purchased.