nmos Posted January 24, 2012 Share Posted January 24, 2012 I have a 97 Impreza OBS that has been "losing" coolant for a couple of weeks now. What appears to be happening is that when the engine is hot it is spitting far too much coolant into the overflow/expansion bottle which then overflows. Then when it cools down again there isn't enough coolant to re-fill the radiator. I'm planning to swap the radiator cap but is there anything else I should be considering? Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted January 25, 2012 Share Posted January 25, 2012 (edited) You have likely blown headgaskets, the exhaust gases are mixing into the coolant chambers and blowing your exhaust gases out the overflow, instead of out the tailpipe. Your engine is not supposed to do that one. was there any recent coolant flushing? You could have a bad cap, or a trapped air bubble, but repetedly buddling out the overflow is bad. Change your radiator cap with a new one to start. On a cold car, fill the radiator, and put coolant in the overflow to the mark. Start car. Let warm up like 5 minutes, then pop hood, and open cap to the overflow jar. Look down in with a flashlight. Do you see lots of bubbles when the car is running? Edited January 25, 2012 by bheinen74 Quote Link to comment Share on other sites More sharing options...
nipper Posted January 25, 2012 Share Posted January 25, 2012 I'm just since someone beat me to it Quote Link to comment Share on other sites More sharing options...
nmos Posted January 25, 2012 Author Share Posted January 25, 2012 Thanks. Sure hope you guys are wrong:) Just got back with the cap and am waiting for it to cool off. How big a project is a head gasket on a 2.2L? Quote Link to comment Share on other sites More sharing options...
davebugs Posted January 25, 2012 Share Posted January 25, 2012 A 2.2 you can do in the car. ALthough I always pull them. I think you do a better job with it pulled. And can reseal the baffle plate and stuff while you're at it. Hard in my opinion to make SURE surfaces are good and remain clean during assy with the block in the car. To me it's just easier to pull the engine. And take advantage of that to do any other work. Like perhaps check the clutch if a stick, etc. Quote Link to comment Share on other sites More sharing options...
davebugs Posted January 25, 2012 Share Posted January 25, 2012 2.2's don't usually cause the "bubbles in the overflow" though. That's a classic 2.5 symptom. Quote Link to comment Share on other sites More sharing options...
nmos Posted January 25, 2012 Author Share Posted January 25, 2012 2.2's don't usually cause the "bubbles in the overflow" though. That's a classic 2.5 symptom. When I came home earlier this afternoon I checked the level immediately without shutting it off and the level in the reservoir was very high and there was obvious signs of spillage. I think I did note a few bubbles but just a few. A couple minutes after shutting it off the reservoir was nearly empty. Quote Link to comment Share on other sites More sharing options...
davebugs Posted January 25, 2012 Share Posted January 25, 2012 The marked low level is rather low in the bottle. When cold if you open the rad cap do you see coolant? I'm gonna go back and reread the thread to see what's going on. Perhaps you just need a proper "burp". Quote Link to comment Share on other sites More sharing options...
nmos Posted January 25, 2012 Author Share Posted January 25, 2012 When cold if you open the rad cap do you see coolant? Yes. Just changed the cap. Coolant was a bit warm but not hot and the rad was full. Took it for a very short spin and will take a longer drive in about an hour to see what it does. Quote Link to comment Share on other sites More sharing options...
davebugs Posted January 25, 2012 Share Posted January 25, 2012 I'm about done for the night. But has any work been done recently? I'm leaning towards the burping question. WOndering if air got into the system by somehting other than HG's and is still stuck in there basically. Because properly draining to make sure it's burped is a little messy. And if you don't know it has an OEM thermostat that would be hte time ot change that - or the fancy NEWSTYLE upgraded Stant (the basic Stand replacement is really wimpy). Quote Link to comment Share on other sites More sharing options...
the3rsss Posted January 25, 2012 Share Posted January 25, 2012 This one is kinda easy. Either s bad radiator cap or head gaskets. Quote Link to comment Share on other sites More sharing options...
nmos Posted January 25, 2012 Author Share Posted January 25, 2012 I'm about done for the night. But has any work been done recently? Nope, nothing but oil changes for 50K+ (I'm at 180K). I did notice some "gurgling" noise after shutting off the engine earlier which I now believe may have been coolant boiling off due to a stuck open rad cap. I just took it for a drive (about 10 miles each way) on the freeway with the new cap and so far so good. I've got a much tougher drive tomorrow, about 60 miles down the mountain and 60 miles back up so if I don't end up coming back on the back of a tow truck it's probably fixed Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 25, 2012 Share Posted January 25, 2012 Definitely could have been the radiator cap. If that doesn't fix it - then you have blown a HG. Don't pass go, don't collect $200. Been there, done that, got the t-shirt. More times than I can count. GD Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted January 25, 2012 Share Posted January 25, 2012 Definitely could have been the radiator cap. If that doesn't fix it - then you have blown a HG. Don't pass go, don't collect $200. Been there, done that, got the t-shirt. More times than I can count. GD want to see the "Club T shirt" Quote Link to comment Share on other sites More sharing options...
vasy Posted January 25, 2012 Share Posted January 25, 2012 Nope, nothing but oil changes for 50K+ (I'm at 180K). I did notice some "gurgling" noise after shutting off the engine earlier which I now believe may have been coolant boiling off due to a stuck open rad cap. I just took it for a drive (about 10 miles each way) on the freeway with the new cap and so far so good. I've got a much tougher drive tomorrow, about 60 miles down the mountain and 60 miles back up so if I don't end up coming back on the back of a tow truck it's probably fixed I have a 96 2.5. Every time after I changed coolant and burped the system in the past 15 years, I used a modified radiator cap (for a few days) which essentially functions as a stuck-open cap. This way more trapped air can bleed out as I drive the car. I can tell you that, with a properly functioning cooling system (as mine), a stuck-open radiator cap will not cause the coolant to overflow the plastic reservoir (if the coolant level with a cold engine is right at the full line). The reservoir will show a coolant level about 1-2 inches higher than normal with a hot engine, but will not push coolant out of the reservoir. When I shut down the engine with the modified cap on, I've never heard any gurgling sound as you described. Of course, changing to a good cap is always a good trouble-shooting step. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 25, 2012 Share Posted January 25, 2012 a stuck-open radiator cap will not cause the coolant to overflow the plastic reservoir We aren't talking about a stuck-open cap. We are talking about a seal or spring that can't hold full pressure. Your's never develops pressure - a failed cap will develop some pressure but not hold the full 13psi that the system is designed to run at. I've personally seen failed caps cause this exact symptom. One of my customers experienced it not long ago - I got a call to come look at her car because it was overheating - I got there and coolant had overflowed the bottle. I filled it up and ran it to operating temp and coolant could be clearly seen running out of the overflow tube into the bottle. I cleaned the cap seal and got it to stop even though the seal was pitted and cracked. Replacing the cap the next day solved the problem and it's been fine for about a year since then. GD Quote Link to comment Share on other sites More sharing options...
Mike104 Posted January 25, 2012 Share Posted January 25, 2012 Subaru released a Service Bulletin 09-45-06 that talks about a poorly sealing radiator cap can cause the cap to not maintain pressure. That could as GD says allow the fluid to pump into the overflow tank. Here is a link: http://www.scoobymods.com/showthread.php/radiator-cap-cleaning-7337.html?t=7337 Quote Link to comment Share on other sites More sharing options...
nipper Posted January 25, 2012 Share Posted January 25, 2012 A failed cap could cause this to happen like GD said. Quote Link to comment Share on other sites More sharing options...
ronemus Posted January 26, 2012 Share Posted January 26, 2012 This can also be due to a worn water pump bearing;at high RPMs air is drawn in, over-pressurizing the system and blowing out the coolant. A water pump is much less effort and expense than head gaskets, so it's worth checking. A very slow leak of coolant when standing can result in big problems at high RPMs since air is much less viscous than coolant. Quote Link to comment Share on other sites More sharing options...
the3rsss Posted January 26, 2012 Share Posted January 26, 2012 If a bad water pump sucks in air, then where is the air coming from? It's a closed system. Quote Link to comment Share on other sites More sharing options...
nmos Posted January 26, 2012 Author Share Posted January 26, 2012 Well, it looks like the radiator cap was it. I drove around 120 miles total with about 3000ft of elivation change each way and the temp stayed rock solid with no fluid loss. Thanks to everybody for all the help. Quote Link to comment Share on other sites More sharing options...
ronemus Posted January 26, 2012 Share Posted January 26, 2012 It sucks it through the worn bearing. It's a simple sleeve bearing, so clearance develops as it wears. The area around the inside of the bearing is low pressure, so air is sucked in. This isn't just an idea - I've had it happen to me. Mine really let go, and was able to blow out most of the coolant in less than a minute at highway speeds. Quote Link to comment Share on other sites More sharing options...
the3rsss Posted January 27, 2012 Share Posted January 27, 2012 I still don't understand know how a closed system under high pressure can suck in air, someone please explain to me how this is possible. Quote Link to comment Share on other sites More sharing options...
roger1 Posted January 27, 2012 Share Posted January 27, 2012 Sounds like problem solved, but a HG test works by taking of rad cap with cool engine and watch for bubbles in rad. I say cool because I don't to get the pressurized hot water in my face. Quote Link to comment Share on other sites More sharing options...
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