friggeth

2000 Civic LX
D16Y7 Engine, stock
P0117 CEL

My friend's car started losing coolant a few months ago, no white smoke, no oil in the coolant or vice versa. All the hoses were good, no notice of coolant loss watching the hoses and radiator with the car idling, bled the system multiple times. While bleeding the air from the system I've always raised the front of the car and turned the heater on max heat/air to help facilitate the process. Last week it started losing coolant so quickly that it needed to be replaced every day. Then yesterday they said the car kept getting so hot that they had to pull over multiple times to put more coolant in, at some point it got hot enough to set the code P0117. When I checked the car the radiator had a 3 inch long crack behind the filler neck, and a small hole on the front of the neck, and it had sprayed some type of light brown fluid from the radiator onto the surrounding hoses and coolant overflow tank, which after drying turned into a light brown powder. Still no oil in the coolant or vice versa, and the transmission fluid looks normal. I replaced the radiator and hooked everything back up and put some Prestone radiator flush/cleaner with plain distilled water, and shortly after starting the car it starts to slowly leak white foam out of the radiator filler neck, similar to the foam on top of soda when you pour it into a glass. After draining and refilling the radiator four times with only distilled water, it still does this. Along with the foaming, the car stays around 2k RPM for about a minute, and then develops a surging idle that ranges from 1200 RPM to 2100 RPM. I've only run the car for 3 minutes at a time, then letting it cool down for 20 minutes. In that time though the radiator gets hot to the touch, which I was under the impression shouldn't happen with a closed thermostat, and even with a stuck open thermostat the coolant should take a long time to warm up. Since it's possible for exhaust gases to enter the coolant, would that lead to the heat from the gases being transferred to the coolant, and thus to the radiator? Any help would be appreciated.

tony_2018

This does sound like a head gasket issue. My sisters car had the same issue, it was too late to replace the gasket as I didn't have time to replace it. Best part was she got an automatic b20b in her integra and her sedan is fast as ****.

friggeth

Sounds like a pretty mean car. My friend bought a backup engine and transmission for their car a few months ago, I believe the engine is another D16Y7. Before actually doing anything too labor intensive I wanted to narrow down the problem because nothing else quite fits the symptoms. For example I've read that a clogged air bleed hole in the thermostat could cause air to stay in the system and be agitated by the water pump, causing foaming. Another cause of the foaming was said to possibly be caused by the flush, but after four drains and refills with distilled water it's still the same. And neither of those fit with the radiator getting hot after only 3 minutes.

tony_2018

there is no bleed hole on the obd2 d16y7. In order to bleed coolant you run the heater and leave the radiator cap off. Little by little air bubbles start appearing and you just add coolant that way.

Edit: I think you should switch to coolant fluid and not use water.