red95lt1

Well i had one more bolt to go till i get the heads off and i get to see how bad my head gasket was. Well i got the head off and there was my head gasket, intact and perfect.
I went up to my buddies shop and they looked at the heads and they said they were fine. Now my question is why when i did my compression test it was 60 psi, but on the other side it was like 140 psi. Could it be something with my piston? It leaks antifreeze bad and it was smoking out of the breather on the valve cover. What else could be my problem?

shoebox

If you did the compression test correctly, rings, valves, valve seats are suspect. What were the symptoms?

Dave C. '97 Z28

Is there water in the oil? If so, maybe your block is cracked?

Otherwise, check for a bent valve and/or worn valve guides.


-Dave C. '97 Z28

kirschman

Is it leaking anti-freeze or burning it? I just replaced a blown gasket last week on my ride. Look at all the plugs, and the exhaust valves. Mine was blown on the no. 1 cyl. Plug was wet, piston top and exhaust valves where kinda brownish in color, due to the coolant "cleaning" as it was burning in the cyl. Once I got the head off u could barely see where it was blown. U need to look carefully at the gasket, mine was leaking around a bolt into the cyl. and u could barely see where it was leaking. If your losing coolant,and its not leaking, brown oil(water in oil), steaming out the exhaust pipe, or shooting coolant out of the rad. then its either gasket or cracked head. Has to be one of the two if u have any of those symptoms, look at everything again closer.

red95lt1

i did do the compression test right. The symtoms are it was backfireing ALOT i mean almost every second. It took it awhile to start, smoke out of the tail pipes and out of the breather on the valve cover, i had to refill my antifreeze almost every couple of days, and it had a hard time reving. It just wasnt smooth when i reved, and it had a slow response when i reved.

shoebox

Your plugs should have told you if any cylinder was burning coolant.

red95lt1

What would my plugs look like if it was burning coolant? When i pulled them they looked like i was running REALLY rich and i found oil on a couple of them.

shoebox

They would be light color and look very clean.

red95lt1

Well here is something else i found. I went out and checked the gasket very close and i didnt find anything. I looked at the pistons and 3 of them were holding antifreeze in them and one wasnt. So i pored some in the one that didnt have any and it didnt leak through. But i went back about 2 hours later and i looked again and it had leaked through. All the other pistions still had the antifreeze still standing there. Does this even mean anything. Maybe a cracked block, or pistion? I have no idea.

red95lt1

????

shoebox

Was that the cylinder with the low compression? You need to look at that thing with a magnifying glass.

Vader

When glycol gets into a cylinder and causes a misfire, the piston and combustion chamber will not be "cleaned". The effect will produce the oily appearance you have seen. Normally what carbon is present can be wiped off easily after a cylinder has seen glycol antifreeze. Pure water, fed into an engine that is running properly and not induced to misfire will clean the cylinder. Antifreeze doesn't do that.
The coolant will migrate to the cylinder across the fire ring, which is the steel ring around the bore hole in the gasket. Look carefully at that area. In these engines the ring will be distorted and possibly move into the cylinder area or look burned through.
In many cases it is the corner cylinders that blow the head gasket due to poor clamping loads in that area. Number 7 and 8 are particularly prone to this.

shoebox

Apparently all the blown head gasket cars I have ever seen had low concentrations of antifreeze, because they all looked pretty clean <shrug>.