I have a 93 Civic with a stock d15b7. I had oil leaking into my coolant, and a endless stream of air coming up through my radiator. So much so, it blew my overflow cap off... So, I replaced my head gasket. I STILL have a steady stream of air, but no more oil in my coolant... I know I should have checked the head for warping, but it's never overheated and I thought it would be good.

Is there any other possible way air can get into the cooling system? I'm not loosing any coolant, no visible leeks or smells, nor am I burning it. It causes my idle to surge a bit, which should be because of air reaching the IACV. Could there be a small leak by a clamp sucking in air? I know it's pressurized, and it should leak out, but I have read the bleeder valve can draw air into the system if it's not bled correctly.

I know some Chevy and GM's the intake manifold gasket can leak air into the cooling system (or coolant out), but I don't think that's the case with Honda.

Any suggestions would be appreciated. Other than the idle surging and air in coolant she runs great, so I'm confident I replaced the gasket correctly.

 

cracked or dropped sleeve, warped head, cracked head, or thousands of other possibilities.

 

sounds like the HG is still leaking. best way to tell is to do a leakdown test on all 4 cylinders, and do it with the radiator cap off and the coolant topped off. if the coolant rises at all when you pressurize a cylinder, then the HG is definitely still leaking.