Heat randomly stops working and temps shoot up
Thread Starter
Registered!!
Joined: Nov 2014
Posts: 2
Likes: 0
Rep Power: 0 
Heat randomly stops working and temps shoot up
Strange, I posted this 2 hours ago but I can't find it anywhere.
Anyway, I have a 2004 Civic LX, 4 door, automatic. The car normally takes long'ish to warm up on cold days but I only noticed today because it was taking longer than it typically does and was blowing cold air on the full hot setting. I then saw the temp gauge shoot way up. I pulled right over and shut the car down, started it back up and the temp went down and hot air started blowing out the vents.
It was fine for a few miles, then I stopped at a traffic light and the air switched to blowing cool air again and the temps shot up. I was right next to work so I just pulled in and parked.
Any ideas? I saw the sticky for temp issues but this seems more random. I can call the mechanic but I'd like to have an idea of what I'm potentially facing first.
Thanks!
Anyway, I have a 2004 Civic LX, 4 door, automatic. The car normally takes long'ish to warm up on cold days but I only noticed today because it was taking longer than it typically does and was blowing cold air on the full hot setting. I then saw the temp gauge shoot way up. I pulled right over and shut the car down, started it back up and the temp went down and hot air started blowing out the vents.
It was fine for a few miles, then I stopped at a traffic light and the air switched to blowing cool air again and the temps shot up. I was right next to work so I just pulled in and parked.
Any ideas? I saw the sticky for temp issues but this seems more random. I can call the mechanic but I'd like to have an idea of what I'm potentially facing first.
Thanks!
If you think a good mechanic is expensive, try hiring a bad one
Joined: Dec 2011
Posts: 32,017
Likes: 256
From: Midwest. Aiming about mid-chest
Rep Power: 517 
Re: Heat randomly stops working and temps shoot up
The system 'ghosted' your first post for some reason.
Symptoms listed are usually caused by low coolant level, typical root cause is head gasket failure (if external coolant leaks are not found).
Most people will find their coolant has puked out of the overflow bottle covering the battery and fan shrouds, while the coolant level inside the radiator is found to be very low.
Also, many people (mechanics included) aren't able to correctly diagnose the head gasket problems in this particular engine on the first try because it may pass every typical check they can think of (at least while the leak is small).
You can find a ton of threads on this.
Symptoms listed are usually caused by low coolant level, typical root cause is head gasket failure (if external coolant leaks are not found).
Most people will find their coolant has puked out of the overflow bottle covering the battery and fan shrouds, while the coolant level inside the radiator is found to be very low.
Also, many people (mechanics included) aren't able to correctly diagnose the head gasket problems in this particular engine on the first try because it may pass every typical check they can think of (at least while the leak is small).
You can find a ton of threads on this.
