Does anyone recognize this or know what it might be?

I’m having occasional overheating issues, fairly certain there is air in the system as I have no heat.

Trying to rule this out too.

 

Looks like a coolant bleeder screw. Odd place for one, but not necessarily the source of your overheating. First bleed the system carefully to get the air out (follow Billman's thread). If you see evidence of it leaking, or if the problem keeps happening even after a successful bleed, then you might just go ahead and replace the whole hose with OEM or equivalent.

 

Overheating and no heat is a major sign of air in the system. Probably lots of it. Several photo essays here on how to bleed it. Start with the front of the car on jackstands or ramps.

Looks like it's a bleeder or diversion of some type in that hose. Was the car ever supercharged? Hose is aftermarket and no reason for it I'm aware of. Pair of OEM hoses, which will last the life of the car, is under $100 maybe closer to $80. If the antifreeze is suspect or unknown or more than a couple years old I'd replace it with proper Honda Type 2. Takes a little under 2 gallons. I'd personally do it right and install new OEM hoses (the questionable top hose for sure), fill and bleed the system with fresh OEM coolant/antifreeze.

-- Chuck

 

Thanks.

Working on bleeding it now.

Is the rear bleeder really just a rubber vacuum cap or is this some aftermarket nonsense too? This was all on the car when I got it.

 

The system is under about 16psi pressure so the bleeders are little screw valves.

The Lislie funnel is invaluable.


-- Chuck

 

This is what I am referring to. If this isn’t the bleeder, where is it?

front one was easy to find.

 

[edit: nothing to see here lol]

 

No, it was definitely spewing coolant when I opened it. It’s just a rubber vacuum cap, it goes to the heater core.

 

Run the car to temperature -- both fans run -- before bleeding.

Because of the pressure the rubber cap over the rear bleed needs to be held in place with a hose clamp.
The front bleed is on the left side of the engine just below the valve cover and may be hidden behind some hoses.

-- Chuck

Rear bleed:


Front bleed:

 

Tried jacking front of car up heater on full then undo the intake mani bleed.Worked fine for me.