I have a 2004 Honda Civic Lx and I was driving one day and I look down to see if I was speeding or not (easy to do) and I see that the thermostat is almost all the way to the red line. So I pull over to a store and check my fluids. The oil was low so I put two quarts in. There are no signs of leaks anywhere. I also topped off the coolant. Ever sense the care has been fine so could of it been the low fluids? And it being such a quick fix?
You have two signs of an internal head gasket leak: overheating and disappearing coolant. Keep the coolant level topped up in both the radiator and the overflow tank. If the car continues to overheat, have the cooling system pressure tested for a head gasket leak.
If you’re lucky, though, it was just low coolant level. Hopefully it won’t happen again.
It appears you have at least two issues:
You aren’t checking the oil often enough, especially if it was down two quarts without you knowing.
Getting even close to that red line on your temperature gauge means your engine probably overheated. That thin red line is way up on the temperature gauge, with a lot of room in between the red line and where the needle normally sits.
If you’re lucky, everything will be fine, but you should get into the habit of checking your fluids (all of them) every day for a while. If you’re lucky, and the situation goes back to normal, you should get into the habit of checking your fluids every time you fill the tank with gas.
I bought my ''04 Civic new and went thru the “reservoir full-coolant low in the radiator” drill in the late summer of 2010. Yep-head gasket, and after the repair, it has been fine since then.
When the car is overnight cold, check the fluids-oil, and coolant in the reservoir and radiator. Add coolant to the radiator and reservoir as required. The radiator should be filled to the max at the neck, and the reservoir should be at the MIN level when cold. Watch the temp gage, and drive the car for several warmup-cool down cycles. Then, when cold, check the coolant levels. With a head gasket leak, the reservoir and radiator levels will have changed.
With that situation, the nuisance is having to check the coolant levels. The repeated “to the red” overheat will warp the head-BTDT, and in a worst case scenario, will warp the block. The permanent solution is to find a mechanic you trust, and have the gasket replaced.
BTDT = been there done that.
Make sure to keep a very close eye on the temperature gauge for a while. Repeated overheating is something you want to avoid.