Boiling Over

[johnk]

I pulled a stupid. I just put in my new short block and everything was going fine. I drove a few times went to fill the coolant and forgot to put the cap back on. I ran it on the highway and the car over heated I pulled over right away while it was still climbing through normal range (after mid-point). I replaced my cap and refilled the coolant. Now everytime I drive even just a mile it will boil over the coolant. A lot of times it will produce air bubble in the over flow bottle even from short runs.

I tried re-torquing my head studs. One of the middle ones was a little low only 65 ft/lbs. I tried turning them on harder to see if they were down enough first. Then I took them down to 60 and back up to 80 to make sure they were set right. I am using ARP's and had moly lube on them when I installed them originally.

Now the coolant is still boiling over just the same so I did a compression test. I have 8.3 pistons in it. The compression is 190 across the board. When I took the plugs out #2 definitely had some liquid on it. I'm almost positive it was slightly green so coolant got in the cylinder I'm thinking....

What do you guys think I should do? Replace the HG? Anything more? Something different?

I don't think that it's a radiator or coolant/water ratio issue because this will happen even before it reaches full temp. I have had effects start at even a half mile of easy driving.

 

[ddavisaf]

Something isn't right if you've got liquid in the cylinder. You might want to replace the t-stat, rad cap first. Make sure your fan is turning on, and check for small holes or tears in all the rad hoses before you tear the engine apart again.

 

[johnk]

I've replaced the cap and the hoses already. The top hose is getting hot if I run it long enough. That means the thermostat is opening right? Anyway the car will do it on short runs that don't even allow it to heat up to regular running temp.

 

[ddavisaf]

The bottom hose lets you know whether or not the tstat opens.
Check your coolant temp sensor.