I'm an idiot. I clearly screwed something up today and I want to know what you guys think... Here's the deal- I changed the coolant today, filled it up, let the engine idle a little while, followed directions- obviously a simple change, I've done it tons of times, no problem. So I'm driving the car later. I look down and all of a sudden my temp gauge has spiked at the top. Oh crap. I'm on the freeway at the time and get the next exit like a quarter mile ahead, make it to a parking lot, pop the hood. The radiator is cold, the coolant recovery tank is filled to the brim. I take the rad cap off, hear some pressure get relieved, then put the cap back on. When i do that the radiator starts sucking the coolant out of the reservoir. The car is off when this is occurring. I also notice that the engine doesn't seem to be radiating a rediculous amount of heat or anything, as i would expect it to. So the rad ends up sucking down almost the whole tank, and i added maybe a cup of extra coolant and it was full. Start it up, temp gauge goes back down. Drive home, everything is fine, seems that the engine just didn't have coolant.

 

My question is, assuming that the gauge was spiked for maybe 4-5 minutes depending on how long it took me to notice, did something get toasted? This is a 96 legacy, 2.2, auto. 107k miles. My main concern is the head gaskets, while i know they are strong on this engine. I checked the oil cap for coolant residue after driving home- clean as a whistle. Exhaust is clean, no smoke at all. Everything seems as usual. Should I be concerned about some symptoms showing in the next few days? Are there other possible damages other than the HG's I'm forgetting about? I would think I'd need to run it real hot for a longer period of time to blow something like a rod bearing. Again, the engine didn't seem to be radiating any more heat tha normal after this happened. Does the temp gauge spike before it gets so hot to do damage? I really appreciate your help, please pardon my long message- I'm a bit scared . Thanks.

<<Drive home, everything is fine, seems that the engine just didn't have coolant. >>

 

how exactly did you fill the engine with coolant? did you bleed all the air out?

I suspect that you don't need to worry much. You did see the temp spike before too long, you did stop the car relatively quickly after that and you weren't punishing the engine by driving it hard while it was hot.

 

With a 2.2, you're probably OK for the time being. Just remember that with a Sube you have to "burp" the cooling system as you fill it or you will trap a significant air bubble in the top of the engine, near the coolant outlet hose fitting. That's probably what happened, and after you relieved gas pressure by popping the rad cap you saw the overflow tank correctly resupplying the system with coolant to fill the void.

 

Drive carefully the next few days/weeks, and watch it. If you get no further spikes, your HGs are fine.

Thanks for the info. I didn't correctly bleed the air out and I'm inclined to say that was the problem, with an air bubble inside expanding and pushing coolant out. I'll read up on how to correctly bleed out the air so that this doesn't happen in the future.

Well here's an update just to tight up the thread. I just came back from a 700 mile road trip I took between Wed and Fri. The car performed great. Oil is clean and clear, coolant is clean, engine performance is optimum, temp stayed rock solid right where it should be, even with high speed cruising on the highway. Looks like there aren't any lasting effects from the overheat, although I'll keep my eye out. I'm going to continue to be careful, as i should always be anyway, but I'm feeling pretty confident. Thanks for everyone's input.