Just a few "percolating" bubbles for a few minutes. Not foaming. But right now I am very focused on the engine. It is missing after warm up. So head gasket is in the back of my mind.

 

Yeah, it's just returning fluid to the reservoir

 

Or burping air to the reservoir. If you remove the radiator cap when everything is dead cold and the fluid level is at the top, everything is normal.

 

Thanks. So far so good.

 

That's not normal.
Cracked head or blown head gasket.
I've already experienced the cracked head; your symptoms exactly.

Look at the bright side: Time to slip a 350 in there

 

That could be correct, but after opening the system cold the level would likely not be normal.

If a compression leak is driving off coolant, eventually the cool down cycle will not draw enough coolant back into the system, and the level will be low. By running in this manner, the temperature gauge should be pretty high, too.

I'm not saying it isn't a cracked head or failed gasket, but just waiting for feedback on the level over time.

 

How's your water pump?

when my pump crapped itself internally this would happen.

 

I should have mentioned my coolant level was near the bottom of the reservoir. I have a fussy lower radiator hose that keeps insisting on leaking at the pump connection. I suppose a bit of air could have gotten in there.

 

If you know you have a hose that is old, stretched out, bulging, or leaking for any reason it's always best to replace it while you can still choose where you will do the job. Home beats the middle of nowhere hands down

 

I had a similar problem on my 88 5.7L. Car was parked but I would turn it on to keep the battery from dying and found out my fans were not turning on.

 

Have you pressure tested the system?

When I got my 86 it had a failed water pump. I replaced that and all the hoses. Still leaked - the aluminium manifolds like to erode around the coolant ports on the back of the heads. I bead blasted the pitted areas and then filled them with Devon and block sanded it. New gaskets with a thin smear of RTV around the coolant ports. No more problems.

I believe my head gaskets are original 1986 with 160k on them. Seem to be ok so far.

GD

 

If It Bubbles Every Time The Engine Is Shut Down,That's Not Normal.

 

I hoping to avoid cracking open the time capsule. I am close though. In another thread a fuel rail bolt busted off and I am drilling it out with diamond grit hole bits- after I broke off a hardened Ez-out in it. Ugh.

 

NEVER use ez-outs. They don't work on anything with corrosion. Left hand drill bits are your best bet. Beyond that sometimes you have to get out the carbide burr set. About 1/3 of the time I have to install a thread repair and I've been doing broken fastener removal for a long time.

GD

 

i didnt have bubbling when shut down, but after long/hard drives when i would finally get in my drive way and shut down, i would hear(and i did at multiple points verify by watching) water passing into the expansion tank. I replaced my radiator cap with a new one (16psi) and have not heard or seen any coolant expanding into the coolant overflow anymore.