I have a 99 Civic with around 109,000 miles, my original radiator top seam was leaking for a while, just didn't have money to get it fixed. Few weeks ago car almost overheated, temp was sitting normal then shot to red instantly. I turned the heater on full and shut the car off as the temp got back to normal, there was not steam or smoke so it didn't overheat thankfully.

After that incident, I dropped it off at a mechanic. I had them change out the original hoses, radiator, and thermostat. When I checked the work that was done I noticed I still have my original cap.
When I picked the car up, the mechanic told me there was lines to the transmission that were cracked (auto) and he replaced them. He also told me he flushed the system for a quit a while, as there was a lot of black crap built up. Also if it matters or not they get there parts from Carquest.

So driving home, the gauge stays quit low, but I feel heat pouring in the car like the heater is on but it's not. Also when stopping at lights it acts like it wants to stall. I'm guessing the stalling maybe wet plugs and or wires from the flush?
As to the heat I'm stumped, sounds like the fan kicks in as normal, I don't notice any smoke or steam from tailpipe (thinking head gasket). Possible the old rad cap should be replaced?

Edit:
Also forgot to mention the water pump and timing belt was changed out by a Honda dealer about 30,000 miles ago. I also changed out the front 02 sensor (Bosch), Plugs (Bosch +4), Wires (purchased at Honda Service counter).

Thanks in advance

 

Sounds like you ran the system dry. Define heat pouring into the car more. Doesn't sound like a radiator cap issue.

You could have still warped the head with your redline incident.

 

Well my a/c quit a long time ago, so I'm pretty much use to heat..but this almost feels as if I have the heater on. Only other way I could describe it is standing in front of an oven that was just used, feel all the heat coming from it. Feels like from under the dash heat is coming into the car, and in the 12 years I've had this car don't remember it ever running that hot. Someone else I had in the car asked if I had the heater on, as well.

It was almost dry, I was stupid and didn't check the levels, before running to the store. The dump off was just about dry and the radiator I couldn't tell how much fluid was in there. It took about 1/2 to 3/4 of a gallon bottle of distilled water between the dump off and topping the radiator. I drove it home and to the mechanic, both trips it staid half way or under.

 

Yea, you can limp around with a leaky radiator if you replenish it on a daily basis. You almost certainly rain air through the system then, hence the temperature spike....easy way to trash your engine.

The heat thing is probably your heater core valve stuck open. Maybe all the crud that was in your system gunked it up when it got flushed out. When you run a huge air pocket in your cooling system, the aluminum starts to corrode and it circulates it around. Since it's coming into winter time I guess you have some time till it sweats you out.

As for almost stalling at idle after temperature spiking the engine, that's never a good sign. With my experience in Subaru HG failures (there are a ton of them) the stalling is usually a really bad sign that you warped the head or fried rings, cracked block, etc. I would monitor your coolant levels daily to make sure you're not loosing any to make sure your head gasket isn't leaking. Maybe you can see what the mechanic says, but it will probably be a guess at this point. Maybe he can do a compression test. You may want to make sure there's not an obvious sensor that was left unplugged or something.

 

Thanks for the information boiler1, I'll try to contact the mechanic I brought it to and see if he can take another look at it. The idle thing seemed to get better though not completely by the time i got home.

I feel like #$(*% for letting this happen to my Civic, I took care of it all these years, then my health took a turn. No excuse, especially for something as simple as checking levels. It didn't rack up a lot miles with the radiator in this shape, did more sitting then driving.