I have 1997 civic ex d16y8 when I first turn on my heater it’s hot for a little while then turns warm/cold. I have to keep turning it off for a while just to make it hot. I did also notice my lower radiator hose is cold after driving half the day. And my radiator fan does not turn on, I jumped to see if it turned on and it did. I’ve replaced thermostat, radiator, and the fan
Heater blowing warm/cold and rad fan not turning
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Cooling Fan Switch.
It should be the one you unplugged in order to install your jumper.
In my experience:
-These DO NOT respond well to seeing temperatures above operating temp. Furtherly, they seem to be more sensitive to overheating, the older the switch is.
Has your Y8 run hot and/or run low on coolant lately? Keep in mind, the stock gauge may not register a slightly higher operating temp.
-I have tried OE spec. replacement switch(s), and always have some issue with them (Shorter life, Fan ON or OFF at temperatures different than with an OEM part, or even zero Fan OFF function..).
That being said, I would buy a new one from Honda. It might cost a little more, but I'm here to tell you, it's worth it having to only replace it once.
Going forward:
Your 'wonky' heater output is strange, but could also point towards being low on coolant.
Keep an eye on your coolant reservoir, like daily (No joke). Determine if the car is using and/or leaking coolant. Next chance you get, do a Headgasket block test and see if the headgasket is compromised.
This all might seem like 'jumping the gun' towards a headgasket breech, but its worth investigating because if you catch the breech soon/early enough, it can save you time/money in the long run.
It should be the one you unplugged in order to install your jumper.
In my experience:
-These DO NOT respond well to seeing temperatures above operating temp. Furtherly, they seem to be more sensitive to overheating, the older the switch is.
Has your Y8 run hot and/or run low on coolant lately? Keep in mind, the stock gauge may not register a slightly higher operating temp.
-I have tried OE spec. replacement switch(s), and always have some issue with them (Shorter life, Fan ON or OFF at temperatures different than with an OEM part, or even zero Fan OFF function..).
That being said, I would buy a new one from Honda. It might cost a little more, but I'm here to tell you, it's worth it having to only replace it once.
Going forward:
Your 'wonky' heater output is strange, but could also point towards being low on coolant.
Keep an eye on your coolant reservoir, like daily (No joke). Determine if the car is using and/or leaking coolant. Next chance you get, do a Headgasket block test and see if the headgasket is compromised.
This all might seem like 'jumping the gun' towards a headgasket breech, but its worth investigating because if you catch the breech soon/early enough, it can save you time/money in the long run.
You might have a bad thermostat, even having replaced it. Mine did something like what you're describing, it was just the thermostat staying partially open. The fan won't come on if you're not getting up to temperature, and I hope you bled the air out of the system when you replaced the parts.
*Edit: with the engine COLD take the cap off and start the car, can you see coolant flow? Can you see coolant at all?
*Edit: with the engine COLD take the cap off and start the car, can you see coolant flow? Can you see coolant at all?
Is the valve for the heater core opening?
Hoses can have a weird failure mode where an inside layer de-laminates and blocks fluid flow. It's mostly a thing on brake systems, but should be possible on heater hoses too. Maybe it's tied to the cooling system coming up to temperature and pressure? Squeeze the hoses looking for soft or lumpy spots when cold, look for bulges when hot. Or ideally, just remove the heater hoses from the car and use a faucet to test that water flows unrestricted in both directions.
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