DarkDaysX6

Sigh... Regrettably I'm back again guys. My problems are very similar to this poster's problems: https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/endless-bubbles-coolant-2954042/ I know this would technically be a duplicate thread for this reason BUT his thread was as stub and never got finished.

All of the symptoms of his car are exactly the same as my car except I do not have a B-series. I'm running a D16y8 with stock internals. No turbo, no nitro, just an N/A build with an Edelbrock intake manifold. Nothing special or crazy.

Here's what we're dealing with:

-Oil is clean and new looking still, no discoloration or foam. New oil filter too. Less than 500 miles have been driven on it since I completed the build.
-Coolant and oil are NOT mixing, but the coolant reservoir smells a lot like exhaust and contains lots of little black chips or flakes that look like the black surface of the head gasket which would lead me to believe that my head gasket could be ruined. It was not re-used when I set the head and the mating surfaces appeared to be normal and clean. I used new head bolts and torqued them down in steps with the proper specifications too. New radiator cap with no weird residue or wear.
-Just like the other poster, I have endless bubbles in the coolant reservoir. The tank is sometimes steamy too.
-The upper radiator hose bulges out quite a bit after being driven. (Pictured below)
-Temp is normal when driving but if I stop and let it idle it heats up but never dumps into the red. It will be anywhere between floating right above normal to right below high but never completely overheats. It will just sit there and run hot. (Also pictured below)
-The car runs absolutely great and doesn't seem to tick or knock so this is very frustrating and I can't trust the car to safely transport my girlfriend to and from work. It is a bit rough during starting and putters a bit but eventually stabilizes after a few seconds and drives smoothly. This is such a tease.

My instinct tells me that this is definitely a head gasket problem involving a bad seal between a combustion chamber and the coolant jacket, but does anyone else have any ideas of what it could be? Without the oil and coolant mixing I don't think the gasket has completely failed but I surely think that it is on the way out. I plan to pull the head and send it to a machine shop to inspect for cracks or being warped. I really hope the mating surface of the block isn't messed up.

I think it has to be one of three things, or possibly a combination of them:

-Cracked or warped head
-Bad/blown head gasket
-Bad mating surface

Anyone got suggestions or previous experiences?

Former User

Blown head gasket -- Get the block tester kit from AutoZone to verify.

teamXteg

may seem dumb.. is there a chance the thermostat isnt working?

DarkDaysX6

RonJ: That's what my fear is. It really rustles my jimmies though because it was a brand new gasket, although it was offbrand. I'm in the process of ordering an OEM Honda head gasket and swapping them out. If it blows again, do you think it could be the head causing the problem?

DarkDaysX6

teamXteg: The thermostat seems to be okay, but I don't know for sure. The coolant has been flowing alright. Would a bad thermostat limit the coolant flow?

Former User

Did you check whether the head and block mating surfaces were warped before installing a new head gasket?

Was the engine severely overheated?

teamXteg

well the reason i asked i thought (could be wrong) the purpose of a thermostat was it closes to build up pressure on the system and heat. then opens and lets coolant flow through to cool the engine.

DarkDaysX6

RonJ: Never "properly" checked the head or block surfaces before installing the new gasket. I just gave them a good cleaning and a good look-over and they appeared to check out. The eye never compares to exact measurements though. The engine was smooth as butter when I bought it and looked very clean and clear, but the head came from the old engine which slung a rod and completely detonated. The temp gauge never went up but that can't rule out high heat after it seized up. I had to replace the two intake valves on cylinder 4 because the piston came up and hit them repeatedly. Other damage to the head is entirely possible but there didn't seem to be anything visually wrong with it. I looked at the bottom and the passages and none of them seemed cracked to me.

DarkDaysX6

teamXteg: I thought so too. It seemed to open and close fine when I was attempting to burp the air out of the cooling system. I came to the same conclusion that the other poster did - after several tries the bubbles kept coming out. The endless bubbles coupled with the strange exhaust-like smell in the coolant reservoir + black chips/flakes floating around make me think that the exhaust is escaping into the coolant jacket or some other passage between the block and the head. The only question is why? It would lead one to believe that it's a cracked head, bad gasket, or bad mating surfaces. This is becoming a nightmare. I'm not giving up on this swap and I think my persistence is my curse as well. If I was rolling in dough I would cut my frustration and just buy another but that's not an option.

Former User

When you pull the head off again, check it and the block for warping using a precision straight edge.

Also buy new head bolts and torque them to spec stepwise in the proper order as detailed in the service manual.

DarkDaysX6

RonJ: That's what I plan to do. What can you suggest for a precision straight edge? Any tool in specific that you prefer to use? If the block surface is warped, what are the options? This may be a retarded question but can you resurface it?

I found a good price on a used cylinder head so that shouldn't be too big of a problem to replace if the head I have now is cracked or warped, but I realllllllly don't feel like buying another block and starting this swap all over from the beginning again.

Former User

Check at auto parts stores and even Harbor Freight Tools. You also need feeler gauges.

Yes, if it's only slightly warped.

Find a place to download the 96-00 Civic service manual. You need it.

DarkDaysX6

RonJ: Thanks for the picture. I'll pick up a good straight edge tool and check that out. Do you just use a feeler gauge and slide it underneath the straight edge? Should there be a certain size gap between the bottom of the straight edge and the head's mating surface or should there ideally be no gap there at all?

Former User

Ideally, no gap. But the diagram lists the tolerance.

DarkDaysX6

Alright cool. I guess it's time to tear this thing apart again I was excited when it cranked right up and ran flawlessly for about a week or two. Should've known better haha.