fiszka11 Posted April 20, 2015 Share Posted April 20, 2015 (edited) Hello, My Subaru 1999 Legacy Outback had its head gaskets replaced in 2012 at about 150,000 miles. Everything was great until recently when the following symptoms have started (190 000 miles): 1. The overflow coolant tank gets close to full after 30 miles+ drive. (See the video below) 2. The coolant is not sucked back to the radiator after the engine cools off. 3. When the engine is hot and running bubbles are visible in the overflow coolant tank. (See the video below). Video: https://youtu.be/bxdm6YZInR4 4. No signs of oil residue in the coolant. 5. A block test performed by a mechanic did not raise any red flags. 6. No overheating so far. 7. Radiator cap replaced and functioning well. 8. No coolant leak. 9. The hose from the radiator to the overflow tank checked and no cracks or holes have been detected. My questions: 1. What is the typical change of coolant in the overflow tank during normal operation? Is it normal that it gets almost full? 2. How long should it take for the coolant to be sucked back to the radiator? What could be the reasons it is not being sucked back? 3. Is bubbling in the overflow coolant tank normal? Is there anything on this video that would suggest it is a head gasket problem? How commonly is the 2nd head gasket repair needed in a life-time of a car? Thank you in advance for any suggestions! Michael Edited April 20, 2015 by fiszka11 Link to comment Share on other sites More sharing options...
lstevens76 Posted April 20, 2015 Share Posted April 20, 2015 I would go back to the person/company who did the head gaskets. It sounds like you have exhaust gases escaping into the coolant. One fast way to find out is rent a kit + buy fluid at Oreilly's and test for hydrocarbons. Do you know what gaskets they used to do the head job? Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 20, 2015 Share Posted April 20, 2015 Sounds like head gaskets. 2nd failure probability? Depends on quality of the work and quality of the gaskets used. The new MLS gaskets need a VERY flat and VERY clean surface in order to seal properly. "Good enough" is not good enough on this engine. Sealing surfaces have to be perfect or the gasket will fail. You've made it 40k miles, I would have to suspect the quality of the gaskets used. The fast way to tell if its head gaskets is already there, bubbles in the overflow. Don't waste money on a block test kit because it will probably not tell you anything. These frequently pass hydrocarbon tests just fine even when the head gaskets are bad. 1 Link to comment Share on other sites More sharing options...
ccrinc Posted April 20, 2015 Share Posted April 20, 2015 Fairtax is right. We bought a Bridgeport mill so we can mill all our heads and blocks. With so much aluminum in one engine, warpage is very common. If the co. that did the head gaskets didn't at least mill the heads, you were set up to fail from the start. Link to comment Share on other sites More sharing options...
Rooster2 Posted April 20, 2015 Share Posted April 20, 2015 Seeing bubbles in the radiator over flow tank is a dead give away that you have a blown head gasket. Exhaust gas is getting into the cooling system to be the source of the bubbles, and causes over heating. My 99 OBW did a good job of blowing bubbles, when it blew its head gasket. Link to comment Share on other sites More sharing options...
The Sizzla Posted April 20, 2015 Share Posted April 20, 2015 (edited) I just painstakingly confirmed the same in my 91 Legacy. It has a very minor HG leak - exhaust into coolant only. Which means no goop on the oil cap, nothing out the tailpipe. It will scoot around for about 10-15 miles from dead cold until the engine becomes hot enough to start venting into the coolant. How do I know it's not an air bubble? I got ALL of the air out. Massaged the heater lines, ran it with the driver's wheel up on a ramp and vented the cap 2-3 times at temp, let it sit overnight, drove it, burped it again, refilled, let it sit AGAIN, burped and refilled AGAIN - then drove drove drove, ran great, then finally filled up the overflow to the brim again with a nice half-inch head of foam. The car was well cared for before me, so the only telltale was this great volume of gas that I know I vented fully from the system before my last drive. There was a very faint welling of oil when running (teeny pinhead-size drops would appear from below in the filler neck sometimes when running) but that's it. When it's below max operating temp you'd never have a clue. Probably never would've shown up if I only ever took it to the store and back in a day. I have an Ej22 so I can get away with Fel-Pros and a cleanup. Considering how minor my (and your) leak is, it's doubtful that your heads are warped - the leak is opening up only when the engine is warmed through completely AND when it has to deal with the top end of a heat cycle. You've caught it early, yay! I spent a solid week researching and testing since it was so hard to tell if it was just an airlock - I had just changed my thermostat before this happened. Since it doesn't sound like you've cracked your system open at all since this problem started, assume HGs. Edited April 20, 2015 by The Sizzla Link to comment Share on other sites More sharing options...
fiszka11 Posted April 20, 2015 Author Share Posted April 20, 2015 Thank you for all the replies. With 190 000 miles on the car, I will most likely not go for the 2nd head gasket repair, especially that I will never be able to assure they were done properly. The shop that repaired the first head gasket problem is one of the most reputable shops in town, but they keep denying the problem saying that little bit of bubbling is normal, that there is nothing wrong with the overflow tank getting full, etc. The car is really comfortable and great for camping, but terribly unreliable :-(. Thank you all for the input. Link to comment Share on other sites More sharing options...
The Sizzla Posted April 21, 2015 Share Posted April 21, 2015 (edited) Thank you for all the replies. With 190 000 miles on the car, I will most likely not go for the 2nd head gasket repair, especially that I will never be able to assure they were done properly. The shop that repaired the first head gasket problem is one of the most reputable shops in town, but they keep denying the problem saying that little bit of bubbling is normal, that there is nothing wrong with the overflow tank getting full, etc. The car is really comfortable and great for camping, but terribly unreliable :-(. Thank you all for the input. I somehow neglected to mention that my car will eventually overheat once enough coolant has been displaced. If yours does not, the leak has simply not gotten bad enough (or you are catching it before it overheats - I could drive mine around the neighborhood and top up the radiator from the overflow and it'd be fine). I understand why the shop would turn you away for these symptoms; bubbles do happen naturally as part of the standard system, the difference is when the bubbles are from exhaust gas and not normal venting from high internal temperatures. Normal venting will also not cause a froth or a foam on top of the coolant. If you put a lot of money into the repair, drive the car around nearby the shop until it's starting to brim the tank, then find a place where you can drive it relatively hard in a few short bursts. At that point it should really be doing a bubble-churn in the tank and be pretty undeniable. Your video shows what my car did while I was testing it at full temp but before it would actually overheat. I could not get it to overheat in the driveway alone. These internal leaks require a lot more exhaust pressure and heat output to show themselves. As the leak "opens," you will get more of a froth in that foam and your upper radiator hose will go from firm to floppy as the system loses pressure. The fact that it does not go down again (though I would tug the top black tube that goes from the side of the radiator cap into your overflow bottle just a little to make sure it's not stuck against the bottom) is because this is not gas forming from heat within the coolant, it is gas that was not previously present in your cooling system. This prevents the pressure differential that allows your bottle to get sucked back down again later from happening. tl; dr this should be something the shop fixes. You just have a very very very minor leak and the given symptoms from your video would look the same to a tech as someone who overfilled their overflow on a normally-operating car. Edited April 21, 2015 by The Sizzla Link to comment Share on other sites More sharing options...
lstevens76 Posted April 21, 2015 Share Posted April 21, 2015 (edited) 190k is no big deal as long as maintenance has been done. Even when it hasn't you can usually DIY (if your willing) almost an entire car for less than a year worth of cheap car payments. Edited April 21, 2015 by lstevens76 Link to comment Share on other sites More sharing options...
nipper Posted April 21, 2015 Share Posted April 21, 2015 The coolant level will change a few inches during operation. It gets sucked back in to the cooling system as the engine cools off, unless the "sealed" system has a leak of some kind. A leak can be a hose, the radiator or the head gasket. Are the bubles you seeing large and continuous? Link to comment Share on other sites More sharing options...
idosubaru Posted April 21, 2015 Share Posted April 21, 2015 is the radiator cap a Subaru cap? is the sealing surface in the radiator neck - where the radiator cap seats against - in great condition? are there any leaks at all - under the engine, crossover pipes, etc? i assume you have no rust to worry about otherwise there's lots of places to check for leaks. LOL Link to comment Share on other sites More sharing options...
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