hove102 Posted June 9, 2015 Share Posted June 9, 2015 I just became the proud new owner of a Rio Red 1999 OBW, EJ25D, 4EAT, that's had a fair amount of work done by its previous owners, including the timing belt & tensioner, headgaskets, and a full trans service. So far, it seems to run pretty well, but the one weird quirk it has (so far) is that both the Main and Sub Radiator fans seem to be a bit overactive and will often stay on when the car isn't running, but the key is in the ACC or ON positions. The weird part is that when I drove around today in the heat (mid to high 80s) today with the A/C off, the fans didn't stay on, but as soon as I drove with the A/C on on my way home from work, the fans stayed on when I got home. Then, tonight, driving home with no A/C, the fans stayed on again.What I'm trying to figure out is what could be causing this. Bad/unplugged Coolant Temp Sensor? Is the relay getting stuck on sometimes? Are the fans themselves faulty? When I did research on these things before I bought one, I never found anything relating to this topic so I'm kind of at a loss here. I just bought this thing so I'm hoping it's not something catastrophic, as the car runs pretty well other than this weird gremlin. Any help would be appreciated, just go easy on me since I'm new to this whole "Subaru ownership" thing Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 9, 2015 Share Posted June 9, 2015 does seem like it could be the ECU is getting a bad signal from the Engine Temp Sensor. Getting data from it might help with this but, might be a cheap enough part to just throw one on. Even if you're wrong, it eliminates one thing, and you replace a 17 year-old part. you don't have any other relays clicking or odd electronic behavior do you? sometimes people mistakenly connect the green test connectors under the dash and their fans go crazy. 1 Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 9, 2015 Share Posted June 9, 2015 relay or temp sensor 1 Quote Link to comment Share on other sites More sharing options...
hove102 Posted June 9, 2015 Author Share Posted June 9, 2015 (edited) 1 Lucky Texan, where are the test connectors? I know they're under the dash on the driver's side but what am I looking for exactly? The only other electronic gremlin the car has is a speedo that will work for a while, and then stop working and then come back on whenever it chooses, but I know that has more to do with the circuitry in the gauge cluster. Grossgary, do you know which relays control the fans? Edited June 9, 2015 by hove102 Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 9, 2015 Share Posted June 9, 2015 (edited) those connectors activate all the evap solenoids so, probably not an issue. You'd have multiple relays clicking and fans 'cycling' on/off. but, there may be a common ground somewhere affecting the speedo. and the Temp Sensor, or fan relay ? With the age and all the work done, worth inspecting grounds and cable harnesses. GG will have more experience with the specific locations of things. If the fans are on when they shouldn't be and pulling (or tapping) the relay stops them - well, seems like a bad relay. If there are 2 or more identical relays, swap positions to confirm? Edited June 9, 2015 by 1 Lucky Texan 1 Quote Link to comment Share on other sites More sharing options...
hove102 Posted June 9, 2015 Author Share Posted June 9, 2015 those connectors activate all the evap solenoids so, probably not an issue. You'd have multiple relays clicking and fans 'cycling' on/off. but, there may be a common ground somewhere affecting the speedo. and the Temp Sensor, or fan relay ? With the age and all the work done, worth inspecting grounds and cable harnesses. GG will have more experience with the specific locations of things. If the fans are on when they shouldn't be and pulling (or tapping) the relay stops them - well, seems like a bad relay. If there are 2 or more identical relays, swap positions to confirm? Grounding totally hadn't occurred to me, I'll look into that as well. I haven't tried tapping the relays yet but if I can get the symptom to reoccur then I'll give that a shot. Quote Link to comment Share on other sites More sharing options...
hove102 Posted June 9, 2015 Author Share Posted June 9, 2015 Update: tried tapping all the relays and the fan stayed on. It was the fan on the passenger side of the car, which, if I'm not mistaken, is the Sub fan. I know they both work because the main fan was running the other day, and the car doesn't overheat or feel like it's heatsoaking. Should I change the relays anyway, or should I check the grounds and the CTS? Or do all three? Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 9, 2015 Share Posted June 9, 2015 (edited) is there another relay there with the same part number? swap them if so. see if the fans work better. some people have had intermittent fans. Edited June 9, 2015 by 1 Lucky Texan 1 Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted June 10, 2015 Share Posted June 10, 2015 Have you checked the Coolant level? Might consider a coolant change, and put a new Subaru thermostat in it. 1 Quote Link to comment Share on other sites More sharing options...
hove102 Posted June 10, 2015 Author Share Posted June 10, 2015 (edited) Fairtax, I was thinking about that. The coolant isn't low, it was between the markers and I put a splash more water in it (just a tad) to keep it level. I haven't checked to see if the car has the original t-stat in it or not but it doesn't run hot so I'd like to think it's not a cooling issue, but some sort of electrical gremlin, mainly because the symptoms are erratic and not constant. That being said, I know it should have Subaru coolant & conditioner in it. Edited June 10, 2015 by hove102 Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted June 10, 2015 Share Posted June 10, 2015 The guage may not show it running hot, but if the coolant temp is not getting below 194°F when the fans are running, they will not turn off. Even with the engine off, the fans may continue to run. A low coolant level can cause the engine to run slightly warmer than usual, but not read any hotter according to the guage on the dash. A non-Subaru thermostat can cause similar behavior. Coolant to water mixture ratio can also play a factor. If coolant is mixed more than 70:30 (coolant:water) the coolant will not dissipate heat as easily. A 50:50 mix gives better heat dissipation without greatly lowering the freeze point. (Not that the freeze point matters right now, unless you're at the South Pole) Another factor of the cooling system on these engines is proper coolant flow through the heater core and hoses. A clogged heater core can slow the coolant flow going back to the thermostat via the bypass route, and cause the thermostat to close as cooler antifreeze comes into the t-stat from the radiator. A closed stat blocks coolant flow in the block and raises block temperature. This doesn't typically present an issue during the warm months unless the heater core is totally blocked, but it is something worth considering especially on a new to you vehicle. I'm sure you made sure the AC worked (or you at least asked about it, but did you check the heat when you went to look at the car? If it was hot outside... Probably not? 1 Quote Link to comment Share on other sites More sharing options...
hove102 Posted June 10, 2015 Author Share Posted June 10, 2015 (edited) You are right about not checking the heat...it was warm on Sunday, when I bought the car, and I ran the AC the entire hour-ish drive home with no incident (no running hot). The fans didn't stick on that day even though they were functioning, even in traffic with the AC on. The receipt for the timing belt and water pump change, which was the most recent service (done back in April, IIRC) shows 2 gallons of premix on the materials list, so I know the coolant mixture is at least 50 antifreeze/50 water. I'm assuming the easiest way to check for a clogged heater core is to turn the heater on and see how hot it gets? You'll have to forgive me for not knowing a lot about cooling systems; I did my research on these cars before deciding to buy one but I've never driven anything where I've had to think about cooling this much! Edited June 10, 2015 by hove102 Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 11, 2015 Share Posted June 11, 2015 you cannot rely on just looking at the overflow tank's level. You must also confirm coolant is up to the bottom of the rad cap in the radiator. 1 Quote Link to comment Share on other sites More sharing options...
hove102 Posted June 11, 2015 Author Share Posted June 11, 2015 I'm definitely being schooled on this, and that's not a bad thing! I'll check that first thing in the morning. I'm starting to think that it might not be bad insurance to check the t-stat and refill the car with fresh Subaru coolant & conditioner, just so I know what's going on in there. Also, is it easier to replace a clogged heater core or flush it out? Quote Link to comment Share on other sites More sharing options...
hove102 Posted June 11, 2015 Author Share Posted June 11, 2015 Update: checked radiator today, full to the brim with fresh, bright green coolant. Doesn't smell gassy or abnormal. Car doesn't run hot, and heat seems to work (checked it last night), so all signs seem to point towards something electrical unless there's something I'm missing. Quote Link to comment Share on other sites More sharing options...
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