Humming when car is off + coolant leak.
Humming when car is off + coolant leak.
What's up Smart People?!
New to the club. We have a 1987 Firebird 5.0, 305, fuel injected. We just resurrected it after sitting for a time. We drove it and turned it off after it's virgin run. When we came back to it there was what sounds like an electric motor behind the passenger front fender/passenger dash area. There was also a small coolant leak that appears to be dripping from under the car in line with the dash, riding the exhaust pipe on the drip flow. If I turn on the AC (or really just the control *** out of the off position) it'll turn off for the duration of the ride. But when I kill it, it turns back on. I disconnected the battery to stop it). Doesn't seem to leak coolant when it's not running.
Heater core? Something else? Any thoughts/ suggestions for diagnosis or fix. Limited budget, currently triaging fixes. Even a temporary disabling would be helpful till we can see what else is gonna break. Thanks in advance.
New to the club. We have a 1987 Firebird 5.0, 305, fuel injected. We just resurrected it after sitting for a time. We drove it and turned it off after it's virgin run. When we came back to it there was what sounds like an electric motor behind the passenger front fender/passenger dash area. There was also a small coolant leak that appears to be dripping from under the car in line with the dash, riding the exhaust pipe on the drip flow. If I turn on the AC (or really just the control *** out of the off position) it'll turn off for the duration of the ride. But when I kill it, it turns back on. I disconnected the battery to stop it). Doesn't seem to leak coolant when it's not running.
Heater core? Something else? Any thoughts/ suggestions for diagnosis or fix. Limited budget, currently triaging fixes. Even a temporary disabling would be helpful till we can see what else is gonna break. Thanks in advance.
Joined: Dec 2004
Posts: 16,774
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Humming when car is off + coolant leak.
Sounds like hvac blower motor is running, it should have no power going to it in the off position so probably a bad switch. The coolant leak you should lift the car and look by coolant hoses at bulkhead going to heater core.
Joined: Dec 2004
Posts: 16,774
Likes: 1,002
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Humming when car is off + coolant leak.
To temp disable the blower motor unplug the blower motor under the hood at motor or try unplugging the resistors in the hvac box under hood passenger side.
Re: Humming when car is off + coolant leak.
Thank you so much! I’ll try it. I’m sure I’ll be back with more questions. Thank you for your generosity of time and expertise.
Re: Humming when car is off + coolant leak.
Hey folks, we tried unplugging the HVAC motor (the 2 plugs to the front of the motor, pass side, against the fender) and there is still something running. It is in the vicinity of the HVAC motor, but it sounds like it is behind it, deeper in the dash. Any other suggestions? I will try and include the video later, if possible.
Thanks again
Thanks again
Re: Humming when car is off + coolant leak.
Hey folks, we tried unplugging the HVAC motor (the 2 plugs to the front of the motor, pass side, against the fender) and there is still something running. It is in the vicinity of the HVAC motor, but it sounds like it is behind it, deeper in the dash. Any other suggestions? I will try and include the video later, if possible.
Thanks again
Thanks again
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Joined: Oct 2021
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From: Windsor, On
Car: 1984 Trans AM
Engine: 305
Transmission: 700-4r
Axle/Gears: 3.23
Re: Humming when car is off + coolant leak.
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Re: Humming when car is off + coolant leak.
YEESSSSS!!!!! That was it! So simple. Thank you. I just have to address the coolant leak now. It appears to be coming out the heater core. Is there a way to cap it temporarily until I can address it? Do any of you geniuses know which hose is the correct one? I'm assuming the one that goes to the fire wall, passenger side of the engine. Best way to cap it? Thanks again!! I'm so grateful.
Joined: Sep 2005
Posts: 27,918
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Humming when car is off + coolant leak.
which hose is the correct one?
Is there a way to cap it temporarily
Probably not hard to find something at any hardware store. Metal is better than plastic. Thread
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