dunbray Posted April 4, 2017 Share Posted April 4, 2017 I posted this in the "older models" section, but I don't know if that was really the best place for this question, so I am copying and pasting here. I hope that isn't too annoying! Sorry this is going to be a bit wordy, but I want to provide all the info I have in case anything trips an idea for whoever might have had a similar problem. I just spent all day trying to fix an overheating problem. My daughter is primary driver on my 2000 Legacy GT. We have had this car (used) since last Aug 2016 approx. Over 150,000 Have had no problems with cooling. Check engine light was on, with a reading for exhaust gas. The other night she was out driving when it shot steam from under the hood. When I got there, I could see it had come out the nozzle on the side of the place the radiator cap screws on, and that the tube and overflow tank were missing. I drove the car a few blocks home and during that time the temp gauge went pinned on hot. Filled the radiator and couldn't get it to overheat at idle, so took it up some hills, and it spurted. Fans never kicked on. When I turn on the A/C they run whenever the compressor engages, which is intermittent. It isn't very hot here yet. Took it to a shop and they said the head gasket was blown. Purchased a tester (combustion gas in coolant tester), and I got a negative. No other symptoms of blown gasket either. I think they lied. On way home check engine light was flashing. Today I replaced the temp sensor, and the thermostat. I also found my O2 sensor was unplugged, so plugged it back in. I also removed the big tube to the PCV valve, removed the valve and cleaned it, then replaced it. The big tube was cracked and brittle at the end. When I started the car it was clearly missing, and ran worse than ever. I bought a fill funnel to burp the coolant, and a OBD2 reader. reader threw codes 0500, 1514, 1101, 1121, p0303. Those codes relate to speed sensor, Idle air control solenoid, neutral position switch, miss on cylinder 3. The speedo works fine. The engine stopped missing and idles ok now. I cleared the codes, but the check engine light is still flashing. The fans will still not come on, even at temp. When I simply turn the key to run, but don't start it, the fans cycle on and off, both together, then one at a time. My best guess is the ECU thinks the car is going fast enough it doesn't need the fans? But if it's the speed sensor, why is the speedo working? Transmission is working fine. Tested hot at the plug that goes into the temp sensor. Link to comment Share on other sites More sharing options...
r.lee89 Posted April 5, 2017 Share Posted April 5, 2017 The fans cycling on/off with the engine off with key on usually means the green test connector has been jumped since you also mentioned the check engine light is also flashing. As for the over heating its quite possible the head gasket is blown. Those testers dont really work if the head gasket slightly blown. Best way is to do a leak down test with the rad full. If coolant slowly rises from the rad then its blown. I would check cyl# 3 first. Link to comment Share on other sites More sharing options...
dunbray Posted April 5, 2017 Author Share Posted April 5, 2017 I have seen mention of the green test connector under the dash. When I look under there, I see two green harness plugs, but they are both plugged into matching ends. Should I unplug them? If it is plugged in when it shouldn't be, would that make the fans trigger during driving? There is one to the left of the steering column, and another closer to the console. I did have a cylinder 3 miss, but I changed all the plugs just now. No sign of burning oil. The gaps were huge on the old plugs. There was oil in all of the plug wells, which I could easily imagine was causing the miss. It runs better, but the check engine light is still flashing, and the fans still refuse to come on during normal operation unless the ac is on or I unplug the sensor. However with the sensor unplugged the car won't start. One other thing you mentioned though: If I fill the coolant up in the radiator, as the motor runs, the coolant does slowly overflow the fill neck (running with the cap off, of course.) Eventually there is enough expelled it stops coming out, but the top of the radiator also appears to be empty. Are we thinking that the head gasket is forcing bubbles into the coolant, which bubbles then rise to the sensor and cause it to fail to sense? If so, why does the gauge on the dash still work? This is a 2000, and I understand (?) the one sensor runs the gauge and the fans. Link to comment Share on other sites More sharing options...
dunbray Posted April 5, 2017 Author Share Posted April 5, 2017 I just watched a video by "briansmobile1" on youtube. I am now convinced that I do indeed need to do the head gaskets, which disappoints me, as this was my first Subaru and apparently this is a very common issue with them. Had I known, I wouldn't have touched this car. I would have stayed with Honda. In any case, I am going to attempt to change the head gaskets in the next few days, and of course I'll take them to a machinist to be checked and worked. Link to comment Share on other sites More sharing options...
MilesA Posted April 5, 2017 Share Posted April 5, 2017 I just watched a video by "briansmobile1" on youtube. I am now convinced that I do indeed need to do the head gaskets, which disappoints me, as this was my first Subaru and apparently this is a very common issue with them. Had I known, I wouldn't have touched this car. I would have stayed with Honda. In any case, I am going to attempt to change the head gaskets in the next few days, and of course I'll take them to a machinist to be checked and worked. It is a Subaru flaw, especially with models of this vintage. Once the head gaskets are replaced with the correct gaskets with better design, you should not have to do them again. If the car made it to 150K, that is longer than most. It's an expensive repair if you have to pay someone else to do it. If you can DIY, it's not too bad. Link to comment Share on other sites More sharing options...
r.lee89 Posted April 6, 2017 Share Posted April 6, 2017 The green connector should be unplugged. If you start the engine cold with the cap off and it slowly rises within a min or 2 then more than likely its blown. When the head gasket blows it pushes exhaust gases into the cooling system. Which is like air. First symptoms would be no heat then overheating. If the head gasket is really bad the oil can look like milk shake or coffee. Pull the oil dipstick if it looks overfilled could be coolant filling in. For the 3rd gens those are almost guarantee head gasket problems. Link to comment Share on other sites More sharing options...
dunbray Posted April 6, 2017 Author Share Posted April 6, 2017 Thank you for all of your feedback. The upside of this whole very prolonged (for me) diagnostic exercise is that I have found multiple little problems which I have been correcting along the way. I will unplug the green plugs under the dash and see if that helps with the fan problem. Other than that, I plan to actually pull the motor and dissect that sucker. Hopefully, as MilesA says, once done is the only time needed. Too bad Suby doesn't give some sort of allowance for this obvious design defect. Link to comment Share on other sites More sharing options...
GEE-OTTO Posted April 6, 2017 Share Posted April 6, 2017 Yes, tackle all the annoying bits while the engine is out. I would send the heads to be cleaned and tested and have the lash adjusted once its all back together youll have a solid engine for a long while to come. Link to comment Share on other sites More sharing options...
dunbray Posted April 8, 2017 Author Share Posted April 8, 2017 Well, I have it out of the car and the heads stripped off. If it was leaking at the head gasket, it is keeping the secret. There is no sign of blow out, and the coolant passages are clean as a whistle. Little helpful hint for 1st timers like me: when you buy the new $60 head bolts, be aware they only give you the six you need for 1 side. That means $120 just for the bolts, which they say are mandatory in the service notes. Also, it appears someone has been in this engine before me, so the gaskets may have already been replaced. If so, I am even more disappointed, as I was hoping once changed they don't need it again. The radiator is dirty and has a bunch of gunk at the bottom of the fins that I assume is stop-leak. I am thinking I'll replace that, along with all the belts, water pump, alternator, starter, fuel filter and pcv valve, to name a few... Link to comment Share on other sites More sharing options...
dunbray Posted April 13, 2017 Author Share Posted April 13, 2017 Here is the end to the saga! Just in case anyone is interested, I found the answer to my Subaru problem. It is a long story, but the bottom line is: my repairs were flawless. The car was not overheating after the overhaul. The gauge on the instrument cluster went bad, and reads overheat when the temp is really fine. Ran it way past the gauge redline in the shop where we could monitor the actual engine temp, and when it got to the temp where the fans should kick on, they did so. As Spock said: "when you have eliminated the possible, all that is left is the impossible." Moral of the story, if your car shouldn't be overheating, but says it is, get a second opinion! Also: the majority of mechanics appear to agree you can just re-use the head bolts, which I did. I returned the ones I bought. Kudos to O'reilly for crediting me for both boxes, even the one I had opened which said "not returnable if opened" Link to comment Share on other sites More sharing options...
MilesA Posted April 13, 2017 Share Posted April 13, 2017 Thanks for the update. Glad you got it resolved. Link to comment Share on other sites More sharing options...
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