Join Date: Sep 2009
Car Year: 1999
Car Model: Forester S Turbo
I guess the easiest thing you can do to check is fill it up with water (if you are testing and it's leaking there's no point in wasting coolant/dropping it on the drive/in the drains. You can empty the water and refill it with coolant later), start the engine and bring it up to temp, with the in car heater temperature control "full on" because the matrix is obviously now empty. Once the engine is warm to the touch, clean and dry any coolant hoses and all their respective connections/pooling areas, and then restart. If there is a leak it should become obvious fairly quickly. Maybe some cardboard under the car and a good torch will help?
In order to have run the heater matrix dry (no hot air), I summise that the loss of coolant would have been fairly swift. If the HGs suddenly went causing so much coolant loss, the engine would surely have stalled by the over whelming influx of non combustible liquid. If they had been gradually breaking down for a while, surely the engine would have started over heating some time ago? I think the only way you will find a leak is with the engine running and the thermostat open, this is a reasonably easy test for most folks to do.
When you start the Foz, leave the coolant header tank (next to the PS pump) cap off. This will allow you to see what's going on and if there is a continuous discharge of air bubbles long after you have burped the system (taking into account the heater matrix), then the HGs are suspect. This can be observed through the opening and topping up done as needed but again, if you are constantly topping up after the thermostat has opened, then surely there is a leak. If none can be detected outside, how about inside? Or where the heater pipes go through the fire wall?
If all is well (and obviously it isn't), full coolant level should have been achieved within a couple of minutes of the temp gauge needle being at the operating point (about 40% of the gauge arc?) and burping should no longer be necessary after this time. By then, some sort of indicator should have made itself clear to you.
Scruffy 99 S Turbo. TD04-19T hybrid. DeCat. JGM.