Sorry that I am making a big deal of this, but my Subaru is my only and work car, and don't wish to blow it up before it's time, stranding me.

 

Coming back from work this evening and turning off the engine I was greeted by big wafts of white smoke coming from underneath the hood. Closer inspection revealed a fine spray of coolant across the passenger side firewall and smaller puddles on top of the engine.

 

I have a possible explanation for this: little less than a week ago I had done a partial radiator flush where I had removed the radiator drain plug but couldn't get the engine block drain bolts to budge, so I gave it a raincheck for a later date when I had the right tools. Then I refilled with a different type of coolant than I had used before. 2-3 days later I saw a small puddle on top of the engine but assumed it had come from when I had been refilling the reservoir with the new coolant. This morning I saw that the reservoir was empty, so I refilled again. Yet this time I actually mixed Ethylene with Propylene coolant. (Eth. already being in the engine and me adding Prop.) I realize now that this was incredibly stupid. Could this be the cause of the problem, or might it only be a leaking hose that can't stand the pressure? Should I immediatley do a complete drain & flush? Are there any locations to drain the coolant from>

it could be ,the heater hoses right below the spare tire are bad or leaking

there are a couple of small bypass hoses on top of the engine, check them for leaks

find the leak first. get the car up to operating temperature - hold it steady around 3,000 rpm and look for leaks.

 

does your heat and thermostat work fine?

thermostat gasket

 

rad drain cock

 

loose hose

or a bad hose that runs over the top of the motor being hidden from you by the intake. I've seen it a few times....

Get your spare tire out of the way and look

BAM! Found the motherfunker. Yes, one of the bypass hoses had come slightly loose, I had just freaked out because I saw coolant splattered all over the one side of the compartment. But that's no wonder when you're driving 65 at around 3000-4000 rpm, that you'll have stuff spraying all over the place in a case like this.

 

But the coolant mixture, is that still going to cause problems?

But the coolant mixture, is that still going to cause problems?

Glad you found it!

 

Full system drain and refill should do you fine. If you want run a hose through it while the engine is running to clean her out. Or use that fancy flush kit I would definatly drain and switch completly over to whichever one you plan on running.