1997 Honda Civic Temp raising when idling.

Tiny
MYTHORN
  • MEMBER
  • 1997 HONDA CIVIC
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 112,500 MILES
Hi there!
I just replaced the overflow tank as it was disgustingly dirty, the cap for the tank and the internal hose. I notice a bit of leak on the hose leading from the rad (at the reservoir tank), and I think that this is why it's happening (a vacuum seal is not being properly made for the rad to suck fluid back in). Can I get away with a clamp, or do I need a new hose? I have a clamp on hand, a hose I will have to go and get. Thanks!

Ok, I just replaced the hose. I'll let you know if that's it. But if it isn't, what else could it be? I could only think of the Thermostat?
Saturday, February 7th, 2009 AT 12:19 PM

7 Replies

Tiny
F4I_GUY
  • MECHANIC
  • 3,302 POSTS
You may need to replace the hose if the clamp doesn't work. There isn't much vacuum/pressure on that hose so if it's leaking usually its ripped.

If your vehicle is overheating only while it's idling, first thing I'd check is to see if the cooling fan is coming on. If that's in check, feel both rad hoses, they should be around the same temperature if the thermostat is fully opened.
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Sunday, February 8th, 2009 AT 8:25 AM
Tiny
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Well, it happened again. What seems to be happening is that when it's running for a while, especially at highway speeds, the overflow tank just keeps filling up. Then, when I slow down, because there's not much air intake, the temp starts to rise within a couple of minutes. This last time, I let it cool down a bit (only for 30 mins or so) and opened the rad cap. There was no pressure. I took another look at the cap, it seems like the seal ring is compromised. I've just bought a new cap, and hopefully this will finally resolve the problem. I will take a look at the cooling fan, though. Would that cause the coolant to overflow, though?
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Sunday, February 8th, 2009 AT 2:04 PM
Tiny
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Usually excessive/unwanted pressure in the cooling system will cause the overflow to overfill or bubble. Usually this is a headgasket issue unforunately.

Get a leakdown test done on your cylinders, this may be your issue.

Do you have to keep on refilling your coolant?
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Sunday, February 8th, 2009 AT 3:07 PM
Tiny
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Only because the overflow tank itself overflows. As far as I can tell, there is no leakage into the oil or anything like that.

I'll get a mechanic to take a look tomorrow. Thanks!
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Sunday, February 8th, 2009 AT 8:51 PM
Tiny
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Unfortunately like I said, if the coolant in the overflow tank bubbles or overflows it is usually unwanted combustion pressure entering the system. The oil and the coolant don't always mix, that depends on where the leak on the gasket is.

Let us know what happens Mythorn. Goodluck.
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Monday, February 9th, 2009 AT 1:07 PM
Tiny
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Yeah, it turned out to be the head gasket.
*sigh*

Ah well.
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Saturday, February 14th, 2009 AT 11:51 PM
Tiny
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That is unfortunate.

If you opt to repair the vehicle you should send the cylinder head to a machine shop to get re-surfaced and checked for cracks or anything out of the ordinary.

Goodluck.
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Sunday, February 15th, 2009 AT 12:03 AM

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