tlott01 Posted August 15, 2012 Share Posted August 15, 2012 Hello All, My wife recently bought a 1997 Legacy Outback with 106K one owner miles - new car trade-in at a Subaru dealer. We've got a cooling issue and I'm not sure what the exact problem is - we also have a 1990 Legacy that we handed down to her daughter when she bought the Outback. It had classic head gasket symptoms solved when I replaced the gaskets and bolts with new 4 years ago. The Outback never overheats at idle, temperature gauge stays just below the middle of the range when driving (high or low speed). After highway driving the temp starts to climb, then returns to normal. When checking the coolant while running or just after shutdown, there is more coolant in the overflow and a little bubbly - not constant, just occasional. Here's the weird part - after it has cooled off, there is vacuum in the system. The extra coolant is gone from the tank and the upper radiator hose is collapsed. Breaking the vacuum with the radiator cap allows it to expand back to normal. Replaced the radiator cap and just pulled the thermostat and checked it in boiling water - opens quickly and closes when removed from the water. The heater works fine, and running it will cool it down quicker after a high speed run. Fans seem to operate just fine too. Is this head gaskets, or do I have something else going on? Thanks in advance for any advice or insight you can offer. Tracy in Colorado Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted August 15, 2012 Share Posted August 15, 2012 If the radiator cap and overflow hose are working properly it can't pull a vacuum, but if you are starting cold with rad full and fluid in the overflow, and then the overflow is empty, something is not right elsewhere. Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted August 15, 2012 Share Posted August 15, 2012 I know my car spring a leak at the heater core hoses I have the replacements all ready right now it's weeping and I'm sure under pressure more so.. only on very hot & humid days moving in slow traffic under 5 MPH have I seen my temp climb but I don't have my warning set to go off until it hits 210 F normal non humid days have me between 186-197 F Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 15, 2012 Share Posted August 15, 2012 Pushing coolant into the bottle and bubbles indicate one of two things - radiator cap is bad or the head gaskets are bad. Since you already replaced the radiator cap you can probably guess where this goes..... It's almost certainly head gaskets. GD Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted August 15, 2012 Share Posted August 15, 2012 Head gaskets. The collapsed hose is due to air in the cooling system. Air is easily compressible, it's also easily expandable. In normal operation as the cooling system pressurizes with temperature, coolant is pushed out of the radiator into the overflow bottle, where it is stored until the system cools again. As it cools the pressure drops and creates vacuum in the system which draws the coolant from the bottle back into the radiator. When the head gaskets go bad, the same process occurs during pressurizing, except that exhaust gases push MORE coolant out of the system, and then take it's place. Now as the system cools, there is a large air pocket which simply expands rather than pulling coolant from the overflow back in. This causes the radiator hoses to collapse, since they are full of air rather than coolant which would normally hold them in place. Bottom line is you have bubbles in the overflow, and varying temperature during driving, and both of those are key indicators of bad head gaskets. Not to mention, this is an Ej25D, which is the PRIME candidate Subaru engine for head gasket problems. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted August 15, 2012 Share Posted August 15, 2012 I think it is the head gaskets. I have the same motor in my 99 OBW, and it blew it's head gasket. As I speak, a shop is currently replacing the HGs. Yes, with a blown head gasket, the car will idle all day and not over heat. However, just stress the engine with some highway travel, and the temp gauge will spike to HOT. Easiest way to confirm bad head gaskets, is to remove the top off the radiator over flow container cap. With the engine warm, and running, look in, and if you see bubbles in the over flow tank, it's bad HGs. Whatever you do, don't let the motor over heat. If you do, the motor will not be repairable. Sorry to confirm what others have said here about your HGs being bad. Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted August 15, 2012 Share Posted August 15, 2012 I think it is the head gaskets. I have the same motor in my 99 OBW, and it blew it's head gasket. As I speak, a shop is currently replacing the HGs. Yes, with a blown head gasket, the car will idle all day and not over heat. However, just stress the engine with some highway travel, and the temp gauge will spike to HOT. Easiest way to confirm bad head gaskets, is to remove the top off the radiator over flow container cap. With the engine warm, and running, look in, and if you see bubbles in the over flow tank, it's bad HGs. Whatever you do, don't let the motor over heat. If you do, the motor will not be repairable. Sorry to confirm what others have said here about your HGs being bad. Not always true.. I drove 630 miles one way on bad head gaskets.. during the final days turning on the AC and all that extra heat would 99% cause it to overheat.. The thing is not to keep it running with no water flowing in the jackets.. I almost got a ticket one night.. I had a blown lower rad hose PLUS bad head gaskets.. so I ended up driving about 4 miles with the temp pegged.. turning the heat on did not do much good since I had no water. Long story short the ramp off the highway was down hill so I shut the motor off and since it was really early in the morning like 3 AM I blew past a red light so I could keep some air flow.. and what do you know a cop is at the light he saw the steam said his smart remark and let me go. Quote Link to comment Share on other sites More sharing options...
tlott01 Posted August 16, 2012 Author Share Posted August 16, 2012 Thanks for all the feedback - I'm assuming it's head gasket(s). I'm now halfway through the K&W Nanotech block sealer treatment - drained a cool engine, pulled the thermostat, flushed w/clean water, replaced the thermostat housing w/the rubber seal in it, refilled w/clean water and ran for 5 minutes with the radiator cap off to get the rest of the antifreeze out. Drained again and refilled with the nanotech solution mixed with three quarts of hot tap water, started the engine, topped off with regular water, replaced the cap and let it idle for 30 minutes. Shut it down and let it cool for 1 1/2 hours, then drained the system again to cure overnight. I'll leave it alone until I get home from work tomorrow - they say 12 hours to cure, so I assume 20 can't hurt. This is the first time I've used this particular formula, so I'm curious to see if it works. I checked the overflow tank a couple of times while it was idling and no bubbles at all - of course they tell you specifically not to rev or drive it while the solution is in. Again, thanks for all the feedback and I'll let you know if this process works. Tracy Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted August 16, 2012 Share Posted August 16, 2012 block sealant is not going to work because of how the EJ25D blows head gaskets. It's only meant for phase II motors. I think Fairtax4me had a picture of a block that had that sealant crap in it.. looks like it did more harm then good.. cut down on a good amount of size of the coolant passages. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 16, 2012 Share Posted August 16, 2012 (edited) HG fix in a can? You really hate your car don't you? Seriously that crud will F your engine. Probably radiator, heater core and hoses also. It's also very unlikely to even cure properly because unless you pull the block drain plugs there will still be water in the engine around the HG fire rings. The walking cylinders and thick HG's of the 25D will not seal with some block sealer crap - the problem is a design flaw not a small leak that can easily be plugged up. If you can't afford to fix the HG's right then gut the thermostat and it should prevent it from overheating. GD Edited August 16, 2012 by GeneralDisorder Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted August 16, 2012 Share Posted August 16, 2012 When I did my headgaskets (it was a first time for me) I took pictures of the gaskets and you can see what was going on the piston pressurizes the coolant passages as you can see in the picture, it just takes one little spot... Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted August 16, 2012 Share Posted August 16, 2012 Thanks for all the feedback - I'm assuming it's head gasket(s). I'm now halfway through the K&W Nanotech block sealer treatment - drained a cool engine, pulled the thermostat, flushed w/clean water, replaced the thermostat housing w/the rubber seal in it, refilled w/clean water and ran for 5 minutes with the radiator cap off to get the rest of the antifreeze out. Drained again and refilled with the nanotech solution mixed with three quarts of hot tap water, started the engine, topped off with regular water, replaced the cap and let it idle for 30 minutes. Shut it down and let it cool for 1 1/2 hours, then drained the system again to cure overnight. I'll leave it alone until I get home from work tomorrow - they say 12 hours to cure, so I assume 20 can't hurt. This is the first time I've used this particular formula, so I'm curious to see if it works. I checked the overflow tank a couple of times while it was idling and no bubbles at all - of course they tell you specifically not to rev or drive it while the solution is in. Again, thanks for all the feedback and I'll let you know if this process works. Tracy I just had my HGs replaced in my 99, and learned a lot in the process, as to why 96-99 Subarus with the DOHC 2.5 motor break head gaskets. Your motor has a weakness in design, which has the pistons protruding slightly above the head when running. This forced Subaru to use a thicker then normal head gasket to seal the head to the block. Over time and miles, the thick head gasket gets burned thru to permit exhaust gas to enter the cooling system, and hence create the over heating problem. With a block sealer, I don't see how the product is going to correct the problem of a burned thru head gasket. The other down side, is the additive may plug up your radiator and heater core, and that is never good. Well anyway, please report back on this forum what results you got with the block sealer. Who knows...........tell us if it worked for you. Quote Link to comment Share on other sites More sharing options...
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