kruteck Posted March 14 Share Posted March 14 I replaced a timing belt, water pump, and thermostat recently. I drove it for the first time since and I heard gurgling. It dawned on me that I forgot to burp the coolant system. I drove it a few more times with no overheating issues and finally got around to burping it. I rigged up a funnel in the radiator, started the car, and started adding coolant. It took a few cups of coolant, then looked as though it was full, so put a bit more coolant in the funnel and let the car idle for about 5 minutes. It burped once or twice, but that's it. I let it continue to idle. I was expecting the fan to come on at some point, but it never did. This perplexed me a bit because the fan worked prior to and after installing all the new parts. The upper and lower radiator hoses were warm/hot to the touch. No more air bubbles showed up even after 10 more minutes of idling. At this point the coolant started to boil. I put the radiator cap on and shut the engine off. I wouldn't think it's a thermostat issue since both hoses were hot. I suppose it could be the water pump maybe, but it's a brand new Aisin pump. Still not sure why the fans didn't kick in. Any ideas would be appreciated. Link to comment Share on other sites More sharing options...
lmdew Posted March 14 Share Posted March 14 Sounds like you still have air trapped in the system. Temp switch for the fans is up high on the crossover pipe on top of the engine. Is the temp gauge operating normally? Good Subaru, warms quickly to the same temp every time and stays there. Link to comment Share on other sites More sharing options...
kruteck Posted March 14 Author Share Posted March 14 Not sure why I didn't put this in the original post, but the temp gauge was normal. It didn't show the engine overheating. I'll take a look at the temp switch. Thank you. Link to comment Share on other sites More sharing options...
nvu Posted March 16 Share Posted March 16 Check if the cabin heater working. If so the pump is working. Might still be some air trapped in it, try parking at the steepest incline you can and do the radiator fill again. Link to comment Share on other sites More sharing options...
kruteck Posted March 22 Author Share Posted March 22 Finally got some time to get back to this. Cabin heater is working, so not the pump. I also tested the fuses and relays for the radiator fans. They tested fine. I did a bit of research and found out about the green connectors under the steering column used for diagnostics. When I plugged that in and turned the key I heard lots of noises and clicking. The radiator fans were working. I dug into the engine to find the temp switch, per Imdew's suggestion on 3-14-2025, which I believe is also called a coolant temperature sensor. It's kinda buried underneath alot of wiring. I unplugged quite a few electrical connections to give myself enough slack to get to the coolant temperature sensor. I was able to access it and unplug its electrical connection. There was a small hose I wanted to remove to get better access for the wrench, and when I put my hands on it I realized it was broken. See attached photos (#1 and #2). I put a circle around the sensor and a rectangle around the hose. Unfortunately, the plastic nipple is broken. I think I'll need to replace the part the nipple is connected to. Hopefully not, but my gut says that's the way it's gonna go down. Anyone know what this part is? The hose that connects to it goes under the intake manifold and then travels off toward the driver's side of the vehicle. For reference, there is another black nipple to the left of the broken one (see photos #1 and #2). It's intact. The hose that connects to it travels up past the coil. The attached photo (#3) shows a wide view of the hose/nipple that's broken (bordered with a rectangle) and the connection past the coil with a triangle. 1 Link to comment Share on other sites More sharing options...
ocei77 Posted March 22 Share Posted March 22 Been a while since I worked on this series, but IIRC thats the air temperature solenoid. Look at the manual here to confirm. http://www.main.experiencetherave.com/subaru_manual_scans/ There is still some air. Make sure the overfill bottle has coolant. Loosen the top radiator hose. If coolants starts coming out, the block is full. If not, add to the top hose then reconnect. Leave the radiator cap off overnight and check level in the morning O. Link to comment Share on other sites More sharing options...
kruteck Posted March 23 Author Share Posted March 23 So many names for this thing. Purge control valve. Purge valve. Purge Solenoid. Ordered it and the coolant temperature sensor. Will be here in two days and follow up when installed. Thank you guys for your help. Link to comment Share on other sites More sharing options...
kruteck Posted Wednesday at 01:20 AM Author Share Posted Wednesday at 01:20 AM Got the coolant temperature sensor and the purge control valve replaced. Filled the overflow coolant reservoir between the low and high marks. Filled the radiator with coolant and filled the funnel about half way. Started her up. Ran fine. Burped several times. Let it run for about 15-20 minutes. Temp gauge never got above normal. Radiator fans never came on. Coolant eventually started boiling. Shut her off. Will let her cool down, then try again this evening. If I get the same result, I'll leave the radiator cap off and check the level in the morning per ocei77's suggestion. Can't figure this one out. Link to comment Share on other sites More sharing options...
kruteck Posted Wednesday at 04:42 AM Author Share Posted Wednesday at 04:42 AM Update - I let the car cool down for a couple of hours and burped it again. Just when I was about to lose hope... the fans kicked in. Just to be safe, I hung around until they kicked in a second time. All seems good now. Thank you everyone for your advice. I really appreciate it. 2 1 Link to comment Share on other sites More sharing options...
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