Skyhigh001 Posted January 7, 2017 Share Posted January 7, 2017 I am new to subaru's so i need some help, i juat got a Legacy with the 2.5L and i am having overheating problems car has 130k and has had water pump, timing belt and timing belt tensioner and thermostate replaced. I have been bleeding the air from the system but i dont know how long or the best techniques to do. I have tried bleeding with the bleeder screw on right top side of radiator (looking at engine from inside) and running engine till warm and filling up when needed. What else can i try? Link to comment Share on other sites More sharing options...
DGR81 Posted January 7, 2017 Share Posted January 7, 2017 I would check if it has a head gasket issue. That engine is notorious for having head gasket issues. Link to comment Share on other sites More sharing options...
MilesA Posted January 7, 2017 Share Posted January 7, 2017 Did the overheating issue start when you replaced the thermostat and refilled the coolant? Or was it happening before then? Did you replace the thermostat with the Subaru OEM thermostat? Do yourself a favor and use the OEM thermostat and o-ring. And are you sure the thermostat is oriented correctly? If you compare the OEM thermostat to a generic replacement, the OEM one is typically more robust and seems to flow better. The problem that can happen is that air will get trapped close to the thermostat causing the thermostat not to sense the true water temperature, so it is slow to open, leading to overheating. There is a useful tool to get rid of any air bubbles trapped in the system which is the Lisle Spill-Free Funnel Kit Part #24680. It makes this job neat and easy. To bleed the air out of the cooling system, this is a useful technique: 1) (Optional, but helpful) Elevate the front end of the car slightly. Put it on ramps, or park on a slope, etc. 2) With engine cold, remove radiator pressure cap, keep bleeder valve closed, attach Lisle funnel to radiator with sealing cap from the Lisle kit. 3) Top off coolant in the overflow tank to the Full mark. 4) Pour coolant in the funnel slowly to allow air at top of radiator to escape. Fill funnel about 1/3 to 1/2 full. The fluid in the funnel is now much higher than any other point in the cooling system, which will encourage the air bubbles to escape from the funnel instead of staying in the cooling system. 5) Start engine, turn heater on full, heater fan on, keep A/C off. 6) Babysit the car while it warms up, you should see air bubbles coming out at the funnel, the fluid level may drop, add more coolant to keep the level at least 1/3 full. 7) Carefully squeeze the upper and lower radiator hoses a few times to encourage air bubbles to come out. Be careful to stay well away from rotating parts on the engine for safety when doing this. 8) After a few minutes, your temperature gauge should read in the middle range, your radiator fan should come on, and the thermostat should be open. Check that the lower radiator hose is warm. Check that warm air is coming into the cabin from the heater core. Keep adding coolant as necessary to maintain the level in the funnel. 9) Rev up the engine to 2500-3000 RPM and keep it there for half a minute or so, then let the engine idle a bit. You should see fluid circulating when you look into the funnel. Coolant from the funnel will produce steam. This is normal. Repeat two or three times. Eventually, you should stop seeing any air bubbles coming out. Note: if you continue to see air bubbles after all this, suspect a leaking head gasket. 10) Turn off the engine. Ideally, keep the funnel attached while the engine cools, the coolant level in the funnel will drop as more fluid gets sucked into the cooling system, but no air should get in as long as the funnel has some coolant left in it. 11) Insert the plunger/stopper in the funnel, remove the sealing cap and funnel. Dump the fluid still in the funnel into the overflow tank or coolant jug - no spills or mess. Replace radiator pressure cap. Hope this very long procedure is helpful to you. Link to comment Share on other sites More sharing options...
Skyhigh001 Posted January 7, 2017 Author Share Posted January 7, 2017 No i am not sure if its a head gasket issue i have looked at the head found no signs of leaking but doesn't mean its not leaking internally so i ordered a pressure tester to test the system that way and also plan to do a compression test. MilesA i am sure the thermostate is correctly installed and the issue started after a week of driving the car, the temo guage would fluctuate while driving and get hot at idle and once give it some gas it would cool down but than got back up, so i did the cheapest fix first, and thank you for the procedure i will give that a try, where can i get the funnel kit? Link to comment Share on other sites More sharing options...
Setnev Posted January 7, 2017 Share Posted January 7, 2017 Autozone rents out block testers and you can pick up the testing fluid there for a few bucks. It's super easy to use. Drain some coolant out of the radiator, start the car, attach the tester and use the suction to draw air from the radiator into the tester. If the fluid turns from blue to yellow, it's detected exhaust gases in the radiator, which is a good indication of a head gasket issue. I bought the funnel that Miles suggested and it works amazing. It got all the air out of my system. I would do the block tester first before you start throwing other things at it. The engine is the right mileage for head gasket failure if it's never been replaced. Link to comment Share on other sites More sharing options...
MilesA Posted January 8, 2017 Share Posted January 8, 2017 ...where can i get the funnel kit? Amazon has it, other online vendors, some local auto parts stores. I think I paid around $20 several years ago. Looks like they have gone up to $25-30 now, which is a bit expensive, but it is a great tool. Link to comment Share on other sites More sharing options...
Skyhigh001 Posted January 8, 2017 Author Share Posted January 8, 2017 Awesome thanks alot for all the help, i will get the tester and order a funnel kit and let you giys know what happens. Link to comment Share on other sites More sharing options...
Setnev Posted January 8, 2017 Share Posted January 8, 2017 That funnel was the best thing I ever bought. This is the one I got: https://www.amazon.com//dp/B01I40ZQWE I bought it for $23.87 shipped with Prime. Same thing as the Lisle funnel. It's got metal cap adapters and color-coded hard plastic parts. I love it. Miles, I just shot a video last night using the funnel in the same way you posted, ironically, this is how I did it before reading your instructions. I should have the video up in a day or two. Link to comment Share on other sites More sharing options...
Skyhigh001 Posted January 14, 2017 Author Share Posted January 14, 2017 So i was able to get the air from the system with the funnel kit, but now the issue i am having is while driving the heater will blow hot air but once i stop at a light or slow down to turn or let the rpms go to ilde while crusing the heater goes cold while the whole time the temp guage says at normal operating temperature.. Link to comment Share on other sites More sharing options...
Setnev Posted January 19, 2017 Share Posted January 19, 2017 So i was able to get the air from the system with the funnel kit, but now the issue i am having is while driving the heater will blow hot air but once i stop at a light or slow down to turn or let the rpms go to ilde while crusing the heater goes cold while the whole time the temp guage says at normal operating temperature.. Did you check for head gasket? The symptom you're describing is air in the heater core. When the thermostat is closed, the crossover pipe provides coolant to the heater core. If there is air in the system, the water pump takes the coolant and circulates it through the engine via the crossover pipe. If your heater core is emptying at idle, you're effectively starving the top end of the heads of coolant. The engine is overheating, but your gauge will never tell you because its being fed by the coolant from the heater core giving a false reading. The exact thing just happened to my Outback and then I discovered that when I refilled it with coolant, I had either warped the heads or blown my head gasket again because the top end of the motor was being starved of coolant but the crossover pipe had coolant flowing through it and giving me a false reading. Engine never got hot, but I ruined something. Link to comment Share on other sites More sharing options...
Skyhigh001 Posted January 20, 2017 Author Share Posted January 20, 2017 I haven't checked that, would pressure test help figure that out also, i havr the adapter to fit the radiator but at the moment dont have the funds for shop fees or other supplies. Link to comment Share on other sites More sharing options...
MilesA Posted January 20, 2017 Share Posted January 20, 2017 The pressure test would let you know if your head gaskets are sealing or not. If they are sealing, your cooling system should hold steady pressure. Link to comment Share on other sites More sharing options...
MilesA Posted January 20, 2017 Share Posted January 20, 2017 Something else you could try for free, since you got the funnel kit. If you have used the funnel and burped the cooling system, do you continue to see gas bubbles coming out? Those bubbles would be from exhaust gas, not air that was trapped in the cooling system. Link to comment Share on other sites More sharing options...
Skyhigh001 Posted January 22, 2017 Author Share Posted January 22, 2017 Ok great thanks for all the advice i will keep you posted. Link to comment Share on other sites More sharing options...
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