Impreza 2.5i sedan cooling problems

[matt384]

A few days ago I turned on my a/c and noticed hot air coming out, I turned it over to heat and it was super hot. I investigated and found that neither fan was running. I thought well the most common thing would be the thermostat, I changed that and still the same thing, no lights have come on at all. I was told it may be the temp sensor, I unplugged it and the fans came on instantly along with the check engine light and flashing temp light, still super hot air though even with the fans running. I tested the old thermostat by boiling it, it opened so that was a wast of cash. I have ordered the temp sensor from my local Subaru dealer, it should arrive this Wednesday. I'm not sure this will help unless the temp sensor tells the water pump when to start, because I believe nothing is circulating because the top hose is hot and the bottom is cool, I can take off the radiator cap while the car is running and see no movement of the coolant. I flushed the system when I changed the thermostat, so I don't think there is a block, and bleed the system also. I have seen no leaks either the fluid level is stable. If anyone can help or has any Ideas please let me know.

[SD_GR]

I'm a little confused in that you are describing a problem with the A/C but are also describing troubleshooting attempts involving the engine cooling system. Please clarify what the problem is you are trying to diagnose, and which system you have attempted to fix?

[matt384]

I'm a little confused in that you are describing a problem with the A/C but are also describing troubleshooting attempts involving the engine cooling system. Please clarify what the problem is you are trying to diagnose, and which system you have attempted to fix?

The problem is with the car overheating, which is causing the super hot air to come out of the vents anytime the car is running. Sorry for any confusion, not an A/C problem.

[SD_GR]

OK thanks.

If the fans were malfunctioning I think there would be a CEL. The sensor would have seemed a good place to start, however you say you are not getting circulation even though you have burped the system. This doesn't make sense to me.

Since you know the sensor could be an issue and it's on the way anyway, see what happens when you change it. The fans should work if the car is warm enough.

One explanation if I have the sequence of events right is that the sensor has a fault, and you still need to burp the system after opening it up last time to change the thermostat.

[matt384]

Thanks, I will let you know when I get the temp sensor replaced, probably Friday when I'm not working. I did burp/bleed the the air out when I changed the thermostat, I'm just worried it may be the water pump, but there is no leakage there, so I assume it is ok.

[SD_GR]

If you don't see leaking, and the car is running, I would operate under the assumption that the pump's impeller is working, because the pump is directly driven by the timing belt.

If you are indeed seeing no circulation once the sensor is replaced then I would suspect a blockage, but I'd do one thing at a time first though. Hope it goes well Friday.

[matt384]

I was able to change the temperature sensor today with no issues. But I'm not sure at all what my problem is now because that did not fix the issue. Do you think it may be an A/C problem. I can turn the A/C on high and it puts out super hot air, and radiator fans still will not turn on. I'm still not sure if the car is overheating, since I have replaced the temp sensor and the light does not come on, but the heat coming through the vents is almost unbearable, I had to put the windows down today when it was only 32 degrees out. Do you know of any other problem that may be causing this ?

[SD_GR]

The fans should come on with the A/C on regardless of engine or ambient temperature. I'm stumped though, sorry. Bump for more eyes to see this thread and hopefully a better answer than mine.

[matt384]

"Help anyone... Bump"