weldersd Posted June 16, 2011 Share Posted June 16, 2011 1996 auto, (ej 25) new here, I got this car a couple of years ago w/ a head gasket bad. I refurbished the motor myself, I did everything, including water pump and valves. the car has been flawless until of late I noticed that the cooling fans (both) would not cycle normally. I replaced the thermostat, bleed the system, it works good after you let it cool down, then I start it up, it heats up, I feel the thermostat open, radiator gets hot then fans turn on for just a short period of time then shut off, (normal) well after driving it in the city for 30 minutes, I get back to the driveway and I listen. fans don't turn off, I ran the AC while driving but when I hit the slow roads I turn it off. heater blows hot, radiator seems to be clear and un obstructed(water hose flows freely through it) no leaks, not using any coolant, the HG's I used were the updated style. and I do run the conditioner (subaru) I was thinking the coolant sensor in the coolant pipe but like I said earlier, when I feel the bottom radiator hose get hot, the fans turn off right away, after the 30 min use, the bottom hose is cool (no circulation) and radiator feels cool, fan stays on. again, it does not over heat, or even fluctuate when circulation stops. I know I should pull the sensor out when fans stay on, but the lower hose is cool, so the engine is hot, that's why the ecu is telling the fan to stay on, why is in not circulating?? Link to comment Share on other sites More sharing options...
ericem Posted June 16, 2011 Share Posted June 16, 2011 I had this exact same issue with my old legacy I found my heatercore was clogged if you look at a coolant diagram it bypasses through the heatercore when the thermostat closes. What I did was flush the heater core back and forth with a hose, including filled it with water and again flushing both ways express with 100+psi of compressed air and I saw little pieces of stop leak that were clogging the cores. Just incase though I assume your using a new OEM thermostat. I also replaced my ecu coolant temp sensor multiple times as well as thermostat's because it drove me crazy! You can still replace the temp sensor anyway since it's not a bad idea to replace it. Another question a/c is off i assume Link to comment Share on other sites More sharing options...
Olnick Posted June 17, 2011 Share Posted June 17, 2011 and I do run the conditioner (subaru) I may be wrong here but I don't think the '96 EJ25 requires the conditioner. Link to comment Share on other sites More sharing options...
weldersd Posted June 17, 2011 Author Share Posted June 17, 2011 I had this exact same issue with my old legacy I found my heatercore was clogged if you look at a coolant diagram it bypasses through the heatercore when the thermostat closes. What I did was flush the heater core back and forth with a hose, including filled it with water and again flushing both ways express with 100+psi of compressed air and I saw little pieces of stop leak that were clogging the cores. Just incase though I assume your using a new OEM thermostat. I also replaced my ecu coolant temp sensor multiple times as well as thermostat's because it drove me crazy! You can still replace the temp sensor anyway since it's not a bad idea to replace it. Another question a/c is off i assume yes, I tested AC function and it turned on and off w/ ac. I'm going to try to flush the heater core, thanks for your help. why would it work when first started but then later fail? i really don't want to replace a heater core.:-\ Link to comment Share on other sites More sharing options...
weldersd Posted June 17, 2011 Author Share Posted June 17, 2011 I may be wrong here but I don't think the '96 EJ25 requires the conditioner. yes they do, I am running the conditioner Link to comment Share on other sites More sharing options...
ericem Posted June 17, 2011 Share Posted June 17, 2011 Mine was the exact same way i would idle till it warmed up and the fans would cycle start driving it bam exactly what your talking about. I was searching for months and posting sooo many threads about this problem because it would drive me crazy I replaced my rad, 3 oem thermostats, rad caps, running lines differently etc. Blowing out the stop leak crap from my heatercore fixed it. IMO I wouldn't put another dose of subaru conditioner this round. Link to comment Share on other sites More sharing options...
weldersd Posted June 17, 2011 Author Share Posted June 17, 2011 Mine was the exact same way i would idle till it warmed up and the fans would cycle start driving it bam exactly what your talking about. I was searching for months and posting sooo many threads about this problem because it would drive me crazy I replaced my rad, 3 oem thermostats, rad caps, running lines differently etc. Blowing out the stop leak crap from my heatercore fixed it. IMO I wouldn't put another dose of subaru conditioner this round. wow, I bet you have it, I'm looking into flushing core now. Link to comment Share on other sites More sharing options...
weldersd Posted June 17, 2011 Author Share Posted June 17, 2011 Just hooked the garden hose to the inlet/outlet of the radiator core, and flushed both directions for a while, at first it came out as a dribble, then a ton of crud came out and now it flows freely. put it all back together, burped the system, filled it, ran it trying to get the fan to cycle took forever, cooling seemed more efficient, I haven't yet taken it on a long trip but i'm thinking it's good. i'll keep you posted. Link to comment Share on other sites More sharing options...
ericem Posted June 17, 2011 Share Posted June 17, 2011 Great to hear! It definitely cured the problem if you saw that. I always found it odd how it produced good heat even though it was clogged! Link to comment Share on other sites More sharing options...
EVOthis Posted June 17, 2011 Share Posted June 17, 2011 I have seen sticking relays cause this problem, however if both fans are doing it, considering they are run on separate relays I would doubt 2 relays would stick at once... Link to comment Share on other sites More sharing options...
weldersd Posted June 23, 2011 Author Share Posted June 23, 2011 ok, so it's still doing it, intermittent, I just used a hose, should I try the air thing? Link to comment Share on other sites More sharing options...
ericem Posted June 23, 2011 Share Posted June 23, 2011 I dont recall if you answered the question when I asked you but did you use a oem thermostat? Also when you flushed the heatercore if alot of crap came out I would asssume the rad is probably similar. Link to comment Share on other sites More sharing options...
weldersd Posted June 25, 2011 Author Share Posted June 25, 2011 I dont recall if you answered the question when I asked you but did you use a oem thermostat? Also when you flushed the heatercore if alot of crap came out I would asssume the rad is probably similar. I had a oem thermostat, I replaced it with a AM thinking the prob was the thermostat, i'll get a oem, I flushed the rad as well, it flowed water freely, i'm going to pull the motor soon to replace the oil separation plate that is leaking, i'll take the rad to a local rad shop to clean, i'll also try to do a better job at flushing the core. Link to comment Share on other sites More sharing options...
ericem Posted June 25, 2011 Share Posted June 25, 2011 Hmm I would blame the thermostat now maybe because the aftermarket ones are much shorter and don't flow as well. Might as well get a new rad there only usually $100 or so around here new idk if they are reman or w/e but they have lifetime warranty most. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 25, 2011 Share Posted June 25, 2011 Reading this thread reminds me of the early 90's (cars may still do this) but remember how the cooling fans would still run after being turned off until the car cooled? I know Honda's did that but don't know about others. Link to comment Share on other sites More sharing options...
weldersd Posted June 29, 2011 Author Share Posted June 29, 2011 Reading this thread reminds me of the early 90's (cars may still do this) but remember how the cooling fans would still run after being turned off until the car cooled? I know Honda's did that but don't know about others. the problem with this situation is the fans are spinning in vain, the cooland is stuck in the engine block loop bypassing the radiator, the fans are useless. I just flushed the crap out of the core and radiator, they both flow free, now I need to put a oem thermostat in, hope that fixes it. Link to comment Share on other sites More sharing options...
mountainchef Posted June 30, 2011 Share Posted June 30, 2011 You said you replaced the WP when rebuilding engine. I have had issues with refurb'ed WPs, and recently had one fail right after the warranty expired. I decided to run "new" WPs from now on. The symptoms I had were similar to what you're expressing. I did my WP and coolant temp sensor; no more issues. Link to comment Share on other sites More sharing options...
weldersd Posted June 30, 2011 Author Share Posted June 30, 2011 WOW, it was the thermostat, I never had a oe unit in there, it functions beautifully, I flushed the core and rad like a mad man, hope it stays good for a while. No joke oem thermostat are the only things that work in these aluminum subaru engines, I guess it has to do with the high heat sink properties that make the single stage AF therms not function properly. Thanks for the help guys! Link to comment Share on other sites More sharing options...
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