Hi guys. I had to take my 05' Civic EX (183,000 miles, original clutch & MT) to a shop I haven't dealt with. In diagnosing the head gasket problem each time I received the car back they had filled the coolant tank to about 1inch less than the top, clearly way above the Max line.

It seems they did a nice job on the HG, machining etc. They are closed for the weekend and I plan to call them on Monday. But could there be any reason/benefit of filling it up near the top or is it just carelessness?

Also, I'm being paranoid but when driving the heat will be scorching hot but even when the engine is at temp and then I idle for just 10 seconds I can feel the heat decrease to a decently warm temperature. Is this normal for such small engines?

Thanks in advance.

 

The heater not working consistently is a good sign that the cooling system is not completely full. Park on level ground and wait until the engine is COLD. Then take off the radiator cap and confirm that the radiator is full to the top.

 

The return tank should not be filled to the top.

 

Are you checking the coolant reservoir when the engine is at normal operating temperature, or, when it is completely cold?

The coolant level in the reservoir is dependant on the temperature of the engine. If the engine is completely cold, the fluid level will be lower. If the temperature of the engine is of normal operating temperature, it may be fairly high. If you're checking the level when the engine is at operating temperature, then your coolant level sounds just fine. If you're checking it when the engine is completely cold, then yes it is over filled.

 

When COLD, the coolant was 1inch from the cap of the reservoir. I pumped enough out to be right at the MAX line. Thanks everyone for the replies.

Oh and I did check the coolant level in the radiator. I could see coolant right at the top, on the fins but I filled it up into where the cap sits. Later I found out all this did was increase the level in the overflow tank so I guess it was at the correct level to begin with.

 

There should be no air space in the radiator. Should be full to the top all the time. If you have coolant leaving the radiator for the reservoir and not returning, it could be a bad radiator cap, air leak in the hose between the radiator and reservoir, or bad head gasket.

 

Ah gotcha. Since the HG was done a few days ago, I'll try a new radiator cap first. Thanks for the post mk378!

Update: after a short drive (1+ miles) I turned the car off and the temp gauge was at the 4th tick mark. Restarted, said still at the 4th tick and the heat output is luke warm until I get the revs up. Something must be wrong.

Update: well I got a Stantz brand cap and it replaced the exact one that was on there (must have been Stanz). I added about 1 cup of 50/50 right in the radiator to get it all the way up. The same mech that did the HG had replaced the radiator the week before, could this be causing anything, wrong part or something?