dp213 Posted November 1, 2017 Share Posted November 1, 2017 My 98 gt has been getting hot sometimes. I had a leak down test done and that was fine. I then replaced the water pump, thermostat, and radiator. It was fine for a couple days, but now it's doing it again. The only thing I haven't changed is the heater core and this morning I noticed a bit of a film on the lower windshield inside. It's not losing coolant anywhere and it's not pushing bubbles into the overflow. Quote Link to comment Share on other sites More sharing options...
montana tom Posted November 1, 2017 Share Posted November 1, 2017 Are both electric fans working ? Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted November 1, 2017 Share Posted November 1, 2017 Your 2.5 motor is prone to have head gasket problems. I have a 99 OBW with the same engine. It started to over heat like yours. Keep an eye on the temp gauge, when you see the temp going up, stop if you can, open the hood and look if the radiator over flow tank has bubbles in it. If so, then you will know for sure that it is head gasket trouble. Lots written on this subject on this forum, and can be accessed using the "search" feature on top right of the forum page. Don't drive with the motor over heating, it will warp aluminum parts badly, and ruin your engine. Let it cool down, or have it towed if necessary before driving again. Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 2, 2017 Author Share Posted November 2, 2017 Sorry, it has a 2.2 installed. I will check the fans Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 2, 2017 Share Posted November 2, 2017 Subaru thermostat or aftermarket? Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 2, 2017 Author Share Posted November 2, 2017 Subaru Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 2, 2017 Author Share Posted November 2, 2017 Friday I'm going to bypass the heater core and see what happens. Does suck, it's starting to get cold around here to drive around without heat for a while. Lol Quote Link to comment Share on other sites More sharing options...
idosubaru Posted November 2, 2017 Share Posted November 2, 2017 (edited) that's a good test. subaru heater core failure is very rare. internal headgasket failure is more likely. when it starts overheating look for bubbles in the overflow tank and turn your heat on high - if it starts out smoking hot and in a minute or so gets cool - those two things are signs of internally blown HG. those headgaskets are very easy to replace relatively speaking. Edited November 2, 2017 by idosubaru Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 2, 2017 Author Share Posted November 2, 2017 If it had bad head gakets, wouldnt the leak down test fail Quote Link to comment Share on other sites More sharing options...
montana tom Posted November 2, 2017 Share Posted November 2, 2017 Easy way to check the fans is to turn on the A/C , both fans should run. My wife's 01 started heating when pushed hard uphill. a check of the fans showed that the secondary had blown a fuse.. new fuse no more overheat. Your 2.2 is not prone to HG failure (but it can happen) and in my opinion a plugged heater core will not cause an overheat either. You have changed the radiator/ subi thermostat / waterpump... not much left... confirm the fan are working ... if they are, then you can try bypassing the core but order your subaru head gaskets promptly Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 2, 2017 Share Posted November 2, 2017 Do you still have good heat? Try back flushing the core. I stick a water hose nozzle in the heater hose and just let it rip. Flush it both ways a couple times and see if that changes anything. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted November 2, 2017 Share Posted November 2, 2017 Agreed - verify fans and system is properly burped. And make sure the condenser in front of the radiator isnt' all plugged with debris, leaves, bug, dirt, bent all to !%)*%)( from an accident or something. Is there any trend with the overheating - only when going up hill, idling, RPM's, highway? Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 2, 2017 Author Share Posted November 2, 2017 Lower rpms at any speed. If I give it gas the temp starts to drop. Quote Link to comment Share on other sites More sharing options...
golucky66 Posted November 2, 2017 Share Posted November 2, 2017 So just want to throw this out there. I'm not sure about the EJ22 (only worked on that engine once) But on the EJ251/253 where the coolant for the heater core flows from the crossover pipe, through the heater core, then to the nipple on the water pump. In this case, a restricted heater core can cause an over heating condition. (had it happen to two different EJ253's) When coolant goes through the heater core, that hot coolant from it then goes to the water pump. And because where the nipple is on the water pump, it's directly behind the thermostat. If not enough hot coolant is able to make it through the heater core. It won't keep the thermostat warm and keep it open. Once the thermostat closes...well over heating happens. On the two car that i had this issue with. Low RPMS, temperature would spike. Give it gas (above 2.5k) temp goes back down. All while stationary, cruising. Literally didn't matter. Easiest was to rule it out, is as other said and you planned to do. By pass it. But i wanted to share my experience that yes, a restricted heater core can cause an over heating issue. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted November 2, 2017 Share Posted November 2, 2017 The 2.2 motor can develop bad head gaskets, though it is not a common problem. I had that happen on a 91 Leggie years ago. As many have said, look for bubbles in the radiator over flow container. If bubbles seen, then it is head gasket trouble. Quote Link to comment Share on other sites More sharing options...
987687 Posted November 2, 2017 Share Posted November 2, 2017 If it had bad head gakets, wouldnt the leak down test fail No, not necessarily. It's possible it only leaks when things heat up. The fairly deterministic way of telling whether you have an internal headgasket leak is a hydrocarbon test in the radiator. You can get test kits pretty cheap if you want to do it yourself. When it's overheating, do you have heat? When it's overheating, is the bottom radiator hose way cooler than the top? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 3, 2017 Share Posted November 3, 2017 Hydrocarbon test won't tell you anything on these engines. A leak down test is guaranteed, hot or cold. If a head gasket is bad and you feed 100+psi shop air into the cylinder it will leak out and cause bubbles in the radiator. Getting warm at low RPMs isn't a usual symptom of a bad head gasket either. Coolant flow or air flow are factors here. Clog in the heater core will produce overheating in this situation in cold weather. What kind of coolant are you using? Is it mixed 50/50? Radiator fans are definitely working? And good point above, make sure the AC condenser isn't clogged with dirt/leaves and the fins aren't all bent over. Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 5, 2017 Author Share Posted November 5, 2017 Well, I have figured out the fans aren't working. I plugged the green test plugs in and they work, but otherwise they don't work. There are 2 sensors in the coolant tube that goes across the top of the motor, is the single wire sensor feed the temp gauge and the multi wire sensor right next to it the one that controls the fans? Quote Link to comment Share on other sites More sharing options...
sparkyboy Posted November 5, 2017 Share Posted November 5, 2017 (edited) Maybe there is simply an air bubble or your thermostat isn't opening. My 2.2 would get hot on rare occasions, so I would feel the top hose and it would be hot, but the bottom one would be cold, same with the top and bottom sections of the radiator. I fixed it a couple of times by squeezing the hoses and the thermostat would open. I had a failing radiator cap that caused this nonsense. If it just the fans not coming on, the car should cool right back down once you start driving again. These cars have a sensitive cooling system and have to be filled a certain way to minimize air bubbles. Water should flow immediately to the heater core, so if the heater hoses are staying cold, or only one gets hot (check the bypass hose) then you have the right idea about looping the hose so you can drive her until you replace the heater core, but it probably just needs a flush. If the heater core had a leak then it would fog up your defroster, but maybe the leak you have is a tiny one. But small enough to let some air in while cooling off Someone correct me if I am wrong here, but I thought that an easy way to test for head gasket problems was to take the radiator cap off and turn the starter, and if a bunch of coolant squirts out then hg for sure, but maybe that is just for one that is blown and not just leaking a little? Edited November 5, 2017 by sparkyboy Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 6, 2017 Share Posted November 6, 2017 Two wire sensor is for the ECU, ECU controls the fans. Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 6, 2017 Author Share Posted November 6, 2017 So if the 2 wire sensor is bad, does that make fans not work Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 6, 2017 Share Posted November 6, 2017 It will if the ECU thins the engine is cold. It won't turn the fans on. You can check engine temp with an OBD2 scanner to see what temp the ECU thinks the engine is. Fans should turn on around 204°F. Quote Link to comment Share on other sites More sharing options...
dp213 Posted November 6, 2017 Author Share Posted November 6, 2017 Good call. Thank you Quote Link to comment Share on other sites More sharing options...
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