Over Heating Engine after Flush n’ Fill

[Dave]

Hello Everyone;

Within the past three weeks, I’d performed a flush and fill on my 98 Honda Civic Cx, along with replacing the thermostat and within this last week, I’d noticed the needle beginning to rise.

Given that it’s a 98 Civic, it doesn’t have a bleeder valve like the earlier models and I’m starting to wonder if I may still have air pockets. What I did was run the engine with the heater on, while I watching the bubbles pop at the neck of the radiator, and then refilling gradually. In addition I was also mindful on how I installed the new thermostat with the pin at the top.

Presently, I’ve noticed that the upper radiator hose looks collapsed from under the hood, whereas, the car attempts to overheat while driving. The only thing that seems to resolve this problems, is whenever I run the heater at full blast, which brings the temperature needle down to the center of the gauge. From that point, the upper radiator hose appears to be firm again with fluid within it.

Additionally, if I sit at a light, the needle goes up; but whenever I start driving with the heat blasting at me, the needle comes back down.

What does it seem like I’m dealing with?

Topic

[Jim Davis]

Two things to try, run the engine till its warm with the radiator cap loose, and if you have some service ramps, pull the front of the car up on them or get the front of the car higher than the rear while letting it warm up with the cap loose so air can escape the system.

[Dave]

Thank you, I will try both suggestions.

[Lorrin Barth]

As the engine cools after being run the coolant contracts creating a vacuum in the cooling system. The radiator cap should allow coolant to move from the reservoir to the radiator. The upper hose collapsing makes me think this isn’t happening. Maybe it is a bad cap or maybe the hose is plugged.

[Author]

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