mva5142 Posted March 18, 2016 Share Posted March 18, 2016 I have a '99 OBW with 187,000 miles on it. Headgaskets were replaced at 130,000, along with timing belt, water pump and other hard to get to parts. Prior to headgasket repair, new owner put a radiator in it hoping to fix overheating. Also had a new thermostat, water pump, timing belt, tensioners, pulleys and seals at the 100,000 mile service interval. I saw the temp gauge rise about 3 days ago above normal while sitting in a parking lot with the engine running. Got a little above half and I turned engine off, left key on so the fans ran for a while. While driving at speed for 20 miles back to office and then 15 more miles home at 55-60 mph, no issues. I checked coolant ant it was low. I refilled and thought I had it burped well. I took it out and drove about 15-17 miles at 60-70 mph and temp gauge never moved fro it's normal position. I pulled into driveway and let it idle for a minute and temp gauge starts rising slowly. it got to about 3/4 to top before I turned engine off and let fans run. When I checked coolant the next morning after engine had cooled it was low. Started car and let run to operating temp in driveway. I used a kit from Autozone to check fro exhaust gases in the radiator. The type where it pulls air through a liquid and it will change color if exhaust gases are present. Kit says to use it for two minutes. I did multiple times and each time the color of the liquid did not change. I burped the system for an hour and kept refilling the radiator as the level went down. I capped the system and let run for a few more minutes before shutting it down. when I checked after it cooled down, the coolant level in the radiator was good, and it had drawn some in fro the overflow tank like normal. Thinking I had the system burped I drove it last night for 15-20 miles at 60-70 mph and temp was perfect, never moved while driving. Pull into driveway and it starts to creep up after a few minutes then stops, just above halfway. I turn the heater on and hot air comes out and temp drops back to normal. Stayed bouncing between normal and a little over halfway for 5 minutes and then eventually started creeping up very slow. Cooling fans operated as normal, came on when temp warmed up, shut off when cooled back down. The passenger side fan only has four blades and did not look to be running as fast or could feel as much air movement as the driver side fan which has 5 blades and was moving a lot of air. so I have a car that tested negative for exhaust gas in coolant, only overheats after driving for a while, and only when at idle. Headgaskets and water pump replaced 60k miles ago, new radiator 60k miles ago, most likely aftermarket t-stat 60k ago. Any help appreciated. Thanks all. Link to comment Share on other sites More sharing options...
Bushwick Posted March 18, 2016 Share Posted March 18, 2016 (edited) If the radiator was low, then you had to add coolant twice, it's possible it still has air in it. There should be a bleeder screw on the passenger side engine-facing of the radiator. Mine looks like a plastic screw by itself that's really easy to miss, about mirrors the upper radiator hose connection point. Try bleeding it there. Edited March 18, 2016 by Bushwick 1 Link to comment Share on other sites More sharing options...
vtwinjunkie Posted March 18, 2016 Share Posted March 18, 2016 what does the top hose of the radiator feel like? hot? An Oldschool method of getting air out is unscrew the top hose and add fluid after filling radiator to get as much air out as possible. Link to comment Share on other sites More sharing options...
mva5142 Posted March 18, 2016 Author Share Posted March 18, 2016 The upper hose is warm to hot. not something you want to hold onto a while. Forgot to add that the lower hose stays cool-cold for a long time after reaching operating temp. The car will reach temp and stay there for a while before the t-stat opens. You wan watch the coolant level in the neck of the radiator and tell when it opens. It usually takes me running it at 2000 rpm for a bit after reaching operating temp before it opens. not sure if that is normal. Link to comment Share on other sites More sharing options...
Bushwick Posted March 18, 2016 Share Posted March 18, 2016 My lower hose stays cold as well, and seems to remain much cooler than other cars I've owned, and that's with normal temps. Loosen your bleeder screw and bleed the system. Link to comment Share on other sites More sharing options...
Olnick Posted March 18, 2016 Share Posted March 18, 2016 If you think the t-stat is aftermarket, you really should replace it with an OEM or equivalent. 1 Link to comment Share on other sites More sharing options...
Rooster2 Posted March 19, 2016 Share Posted March 19, 2016 From what you have described, it doesn't sound like a head gasket problem. I own both a 98 and 99 Outback wagons. Both blew their head gaskets, and over heated the motor. However, bad head gaskets present themselves with the engine run at high speed, or when motor is laboring, as in climbing long road grades. Over heating does not present itself when the car is idling. Both of my Outbacks could idle for hours without over heating. Bad head gaskets can be identified by seeing bubbles in the radiator over flow tank at time over heating begins. As Olnick wrote, I would suspect a bad t-stat, or perhaps a clogged radiator causing the over heating. New radiators cost only about $100, and is an easy install. Not that you need to install a new one at this time, but good to know it is a user relatively cheap purchase, and an easy install. The burping air out of the cooing system is best done with the nose of the car elevated higher then the rear wheels. It helps to bleed out air with car on an incline, or front end jacked up. Just be careful not to over heat your motor. Subaru motors have a lot of aluminum content that warps under high heat, leading to self destruction. You don't want to be kicking yourself in the butt for ruining your engine. Link to comment Share on other sites More sharing options...
subnz Posted March 19, 2016 Share Posted March 19, 2016 (edited) If cooling system has air in it the BEST way to release air from the system is to run the engine with the radiator cap OFF until engine come up to temperature so that the thermostat opens allowing coolant to circulate and push air out of the system at its highest point at the top of the radiator (open cap) Its a well know fact that air rises through water under motion. No matter how well you refill system (top hose) there will be air trapped in there. Squeezing hoses / parking up hill etc futile and unnecessary. I do this for at least 20-30 minutes. replace radiator cap / switch off engine then top up over flow reservoir to correct level. But as you said you had run motor for an hour? with cap off ? topping up ? this should have been resolved. Your engine could also have an internal head gasket leak ie consuming water ie out the exhaust. Have had this issue before . This can be seen / observed when engine up to running temperature. If the head gasket repair hadn't been done well ie modified replacement head gaskets and if the heads hadn't been resurfaced this could be a reason why H/Gs have failed again. Also if a non genuine Subaru thermostat has been fitted this could be causing issues also so need to replace with a genuine Subaru one as previously suggested also Edited March 19, 2016 by subnz Link to comment Share on other sites More sharing options...
Bushwick Posted March 19, 2016 Share Posted March 19, 2016 (edited) "However, bad head gaskets present themselves with the engine run at high speed, or when motor is laboring, as in climbing long road grades." Clogged radiator fins (like say you drive down a long, gravel road every day and gravel dust is constantly covering the car and condensation causes it to stick) can cause overheating under engine load, even at highway speeds, then run normal temps at idle. I've actually experienced this. Internally clogged rows will reduce efficiency as well as prohibit the radiator from cooling the engine under load (like say tap water is run in the system and deposits build up). My ex had had a VW Beetle with the 1.8t engine, and I did a full timing belt, water pump, etc. and it had air that was extremely stubborn to get out. At idle, for extended periods (winter weather with heater on no less), it'd gradually start climbing, once moving, it'd cool. It took several days to get the air out. Open your bleeder screw and bleed the system. Edited March 19, 2016 by Bushwick Link to comment Share on other sites More sharing options...
mva5142 Posted March 19, 2016 Author Share Posted March 19, 2016 Update, Bled the system good and feel that it is correct. I bought some additional block test from napa that was very dark blue. I didn't feel good that the autozone stuff was new. ALso put a new radiator cap on. Tested with car at idle before thermostat opened, and the block test liquid never changed color. Tested after thermostat opened and liquid turned green. Drove for 8 miles and then let idle in driveway. Took about 1 1/2 minutes and temp gauge started to creep up. I used the block test on the overflow tank as there were bubbles in there. No color change. Temp was just over 1/2 way and not moving. Slowly started to creep up and turned heater on full blast. Temp dropped, still bubbles in overflow tank. Checked again with the block test liquid, no color change, temp started moving up, heater started to blow cold air, temp went up faster. Turned car off, left accessory on to let fans run. Swore a few times too. Unless someone thinks different I think it is the HG. Not sure why the block test liquid didn't change color though. Maybe not not enough exhaust gases to detect, but steady bubbles in overflow and heater blowing cold don't leave much hope for anything else. Link to comment Share on other sites More sharing options...
nipper Posted March 19, 2016 Share Posted March 19, 2016 Have you replaced the radiator cap? Link to comment Share on other sites More sharing options...
mva5142 Posted March 19, 2016 Author Share Posted March 19, 2016 Nipper, Yes, I did this morning and still same issues. Link to comment Share on other sites More sharing options...
Rooster2 Posted March 19, 2016 Share Posted March 19, 2016 Update, Bled the system good and feel that it is correct. I bought some additional block test from napa that was very dark blue. I didn't feel good that the autozone stuff was new. ALso put a new radiator cap on. Tested with car at idle before thermostat opened, and the block test liquid never changed color. Tested after thermostat opened and liquid turned green. Drove for 8 miles and then let idle in driveway. Took about 1 1/2 minutes and temp gauge started to creep up. I used the block test on the overflow tank as there were bubbles in there. No color change. Temp was just over 1/2 way and not moving. Slowly started to creep up and turned heater on full blast. Temp dropped, still bubbles in overflow tank. Checked again with the block test liquid, no color change, temp started moving up, heater started to blow cold air, temp went up faster. Turned car off, left accessory on to let fans run. Swore a few times too. Unless someone thinks different I think it is the HG. Not sure why the block test liquid didn't change color though. Maybe not not enough exhaust gases to detect, but steady bubbles in overflow and heater blowing cold don't leave much hope for anything else. Bubbles in the over flow tank is a big sign of bad H/Gs. I have heard of guys removing the thermostat, and driving on for a while with the bad H/Gs. That means poor heat, and prolly some slight motor drivability issues, but it does help keep down the over heating for a while. Link to comment Share on other sites More sharing options...
subnz Posted March 21, 2016 Share Posted March 21, 2016 ps Also forgot to mention that if the radiator was replaced by another 2nd hand one it may not be any better than the original one. This could be causing issues as well. The only effective way to test a radiators effectiveness is to take it out and get it flow tested by a radiator specialist. Link to comment Share on other sites More sharing options...
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