Hi everyone, Recently flushed my cooling system and now it's leaking from the passenger side, from above the firewall shielding... A lot. I checked for leaks, but everything else looks bone dry from the outside . I had to replace more than 2 cups of coolant after a 20 minute drive. The location of the leak and that it gets worse (doubles) when the defrost is on, to me, points to the heater core. In the past, I would "consume" a lot more coolant in the winter than in the summer. The collective wisdom of this forum tells me that's statistically unlikely. I really hope you're right. Please help. This is taken from below the passenger looking towards the front of the car. You can see the drops of coolant forming. Here's what I did: Lately, my car has been running hot. I started keeping an eye on it and it works go up to 110C/ 230F after which the fan would kick in and it would drop back down under 95/203, but never under 93/199. I leaned that driving at highway speeds or turning the A/C on when in the city would help keep the temperature under 100/212. Thought perhaps coolant isn't flowing through the radiator well (works better when the fan is blowing), so I started by bleeding the system. That helped a bit, but only for the first drive. So I came to accept that I need to overhaul everything, and decided I should start with flushing the system, since I've been slacking on changing the coolant (I don't drive much, but haven't changed it since I bought the car). The dark orange color of the coolant told me it's either really contaminated and broken down OR someone before me put stop leak (manual points to this). I did this by draining the radiator and refilling the system with distilled water one gallon at a time - letting the car warm up each time to open the thermostat and allow everything to mix. One upsetting observation was that during bleeding, little clay like pieces (stop leak pellet material?) would come out of the air bleed valve - but curiously, I didn't see them in the coolant that came out of the radiator. Eventually, I looked under the car during an air bleed process and noticed dripping from the passenger side. Turning the defroster on made it slow down a lot. Now I'm back to an almost 50/50 mixture, but lose a lot of coolant and the remainder boils of because the system can't pressurize. My hypothesis is that the guy I bought it from had the same issue and jammed the heater cores full of stop leak. Within a month of driving the car, the degas bottle was empty. Curiously, the coolant loss didn't continue, so I figured it was just that he forgot to refill it and I've been driving around for a while like that. (he also packed the cabin with air freshener trees so I wouldn't notice the burning smell of oil that was leaking from the cam cover. Hopefully, I'll be a lot smarter about my next car. So anyway, where could this be coming from? The inside of my car is dry. Is there something I can remove or open to see if there's coolant pooling from the heater core? Or where else could this be coming from? A leak from the degas bottle would have to travel upward to get there and also get behind the firewall shield. And there's a lot of coolant coming out too... I'm really hoping you guys have some ideas. I don't have the means (time or space) to change the heater core myself, and taking it to the mechanic's would be a huge investment and one that I don't think I can make. Very bummed out that this is probably the end of the road for my car. Thanks for reading this!