Hello everyone!
Proud owner a recent purchased ‘99 S40 1.6, 108k km for the wifey. Seems well looked after car but having an issue that couldn’t find solution yet.
At start and as I go above 2,5-3k rpm I hear a water running noise that seems rather close behind the center console and my coolant liquid drops to near MIN almost instantly.
No overheating, no water in carpets, just did a new water pump yesterday (had a minor leak), no leakages below the engine bay. AC works perfectly. Where the hell is my coolant going?

Something related with the heater core, a hose, something like that?
Cheers from Porto, Portugal.
There goes some pictures of our first Volvo!

 

Nice looking car!

That water HAS to be going somewhere. Even if it's going into the engine, it's going to be blowing clouds of white "smoke" out the exhaust.

If the problem will happen with the car stationary, I'd suggest you just keep adding water (just water, not antifreeze) and let it keep dropping until you DO have a puddle somewhere. I just had to do the same to locate a leaky brake system (after about a pint of fluid, it finally started dripping off the splash panel that was containing it, running out from a rusty brake hardline).

 

To check for a heater core issue, feel around the carpet in the front foot wells for any wetness. Another sign you will likely have a "sweet" smell when the heat first comes on. Note these cars always run water through the heater core - they control the heat via air doors so do a cold start, set the heat on to open the doors and see if you get an odd smells. As Habby noted, the fluid needs to go somewhere. Common places are heater core or heater hose o-rings (you'd need to pop open the side of the center console to inspect the bottom of the heater core), The hoses from the rear of the block that go through the firewall to the heater core, the upper radiator hose, the overflow reservoir itself and the outside seams of the radiator. Its a closed system so it may need to warm up to build up pressure to push coolant out.