shm91

I changed to a new radiator today morning. The old cap didn't match perfectly, but it's sealing most of it - I don't see coolant seeping out hardly.
I came home with refilled reservoir and rad from 10-mile distance. Now, the reservoir is steaming through the gap under the plastic top, like one from a pot with a top - maybe not that intense by the way.
Advice were the water pump, fan, and the thermostat.

Water pump, I didn't see any leaks under the bottom. But not sure about the possibility of being the pulley slipping or stuck, but I heard it's rare, rather the external leak.

Fan, I tested and it works. Plug connection good.

Thermostat, I changed it right after the recent overheat two months ago.
I'm not sure if I test it, because it stays at the middle all the time so far.
I don't have knowledge if defective thermostat could act like above.

My coolant reservoir is just plastic with plastic top. No rubber sealing.

No leak under the bottom of the car.

shm91

Oh, I remember I haven't bled the coolant, not even bothering turning the heater **** on.
Maybe it's this. Gotta try the next morning.

mechanix619

There's the issue.

You've most likely got a headgasket problem.

Also, a radiator cap has to seal completely. It can't just sort of seal the radiator.

shm91

I guess I'm heading slowly to head gasket issue.

The reason I'm still quite not sure about that is because, the engine compression was 196,182,175,180 three days ago, no leak (at least no change for twenty seconds on the guage).
No milky residue on the oil cap, no white smoke, little bit of sweet smell only before the car is warmed up (this is only sign I see as the sign of the crack).

Though the recent crack on the radiator (might be a pressure, or just being old), and the new rad doing this still got me thinking.

mechanix619

Compression test needs to be done in different stages, cold, warm, oil in cylinder. Doing just one isn't too conclusive.

Make sure everything else is legit, like solid radiator cap, system bleed, ect.

strategy400

You can have good compression and still have a bad headgasket.
I'd still make sure your radiator cap and cooling system as a whole is sealed and keeping pressure in. The system is designed to run under slight pressure and liquid under pressure has a higher boiling point.
Pressure test the cooling system. Get the right cap for your radiator. Get a block tester from an autoparts store and see if you really have a bad headgasket. Then proceed from there.

shm91

Tried to bleed, but the radiator just keeps bubbling incessantly - I can't see any bubble coming up under the liquid, because there's another bubble right under one as chains and four bubbles on the filler neck surface at once always - that much - probably engine pressure.
Oil dipstick smells like exhaust. Hint of sweet smell at cold start. No milky residue - maybe because I changed the oil a month ago.
Could I be certain that it's not any other internal engine issue other than the head gasket?

HondaPartsHero

Block tester

mechanix619

That's not a good sign. That typically means you're getting exhaust gasses entering into the cooling system.

You can keep testing and fiddling with this but because the car has overheated in the past the end result is a head gasket replacement.

A head gasket swap isn't super hard, just time consuming. Be sure to have the head milled just to make sure everything is level. Good luck.

Grape Ape Guy

This is what my 98 did.... new rad cap on old rad, there was a knick in the neck that comes up for the rad cap gasket to seal on. It was allowing the system to run normally and when it got to pressure it allowed the water to boil out into the overflow and out to atmosphere. Warped my head as it never showed steam or anything til it was too late and overheated.

shm91

I'm sure set is better for preventative.
Due to the price difference of about OEM set $200 V. $50 for Felpro valve cover gasket and HG.
Just trying to save money, so, here, asking how much better. It's because exhaust manifold gasket seemed like new a month ago, so, I'm guessing if other gaskets could be fine other than the leaking parts? What's the odd of finding other defective gaskets? Silly question.. I know.. lol

TripleLude

What coolant mixture do you have in there? Too much antifreeze and it will not transfer enough heat. Not enough antifreeze and the boiling point will be too low. I hope you have replaced that radiator cap by now, it is a ticking time bomb that may have already keeled over the HG.

As soon as the gasket-mating part is removed, the gasket is defective. Do not reuse old gaskets that have been heat-cycled, except maybe valve cover gaskets.

It would be awful if you took the time to do this work and didn't replace the gaskets.

shm91

I ordered TYC 2273 radiator. It didn't come with a cap, and I asked the seller and the company of the product for the presence of the cap. Nope. Seller: the product doesn't come with one. Company associate: I don't know. Ask the seller. Just forced the cap on, it doesn't seem to leak, other than the reservoir cap from pressure.

shm91

I honestly would rather have wanted to just see white smokes and milky residue, rather than wasting time guessing, knowing the engine needs fixing soon for whatever is there inside it.

shm91

Today for a short drive of 5 miles, the coolant didn't seem to be lost. The rad cap is unexpectedly holding up, and the reservoir level seems the same. Maybe at least temporarily the bleeding is doing something?