Its a 95 B2500 5.9.
Headed to work at about 5a.m. and noticed the heater wasn't warming up. It was 14 below so figured it might take a few extra minutes. Looked at the temp gauge a few miles later and noticed the I was up to about 3/4 and about 15 minutes out of cell service. Made the bad decision to keep going and kapow the upper radiator blew off. Hooked the hose back up and topped her off w/antifreeze. Temp gauge dropped to normal and stayed there for a couple of miles then shot up again. Started to loose power so I stopped.
Let it cool down and restarted. I have lots of steam out the exhaust, a miss and I am pretty sure I have antifreeze in the oil.


Im sure I have either blown a head gasket or a head. Anything I should do or check before I tear these heads off?

 

Buy aftermarket castings to replace your cracked stock heads.

 

The minus 14 may have cracked it already even before you ran it.

 

I put J@C heads on about 4-5 years (65k miles) ago.
Im hoping I didn't hurt the heads.

 

Im thinking my antifreeze/water ratio was off.
A few months ago I replaced a radiator hose and flushed the system. Only drained it at the radiator drain and added 50/50 antifreeze.
I knew better. I should have checked.

 

It's often just the head gasket or an intake manifold gasket that goes, but heads will warp when run that way. I'd pull 'em off and if nothing is obviously fubar get 'em checked by dye penetrant and magnetic flux inspection and for warpage. You might have got lucky and need just a gasket set.

 

Im usually not that lucky.
Ive got my fingers crossed.




How much antifreeze and how long would it take to hurt the bottom end of my motor?
I let it cool down and drove it about 4 miles before it started to miss. I assume its missing due to thinned out oil.
There appears to be an extra 1-2 quarts in the block.

 

Neither am I, but every now and then the fickle finger of fate is stuck in someone else's backside so misses the opportunity to get me again.

If I'm understanding the question you're asking how much coolant in the crankcase you can get away with, and for how long. The answer is "It depends". When you get enough coolant in there that the oil pump pickup is pulling coolant instead of oil it's not long at all before spun bearings and other nastiness occur. Until then you're probably okay for a little while, but how little that while might be is anyone's guess.

The worst possible outcome that doesn't involve the oil pump sucking coolant is the (relatively cold) coolant causing thermal stress cracks in the (relatively hot) cylinder walls. That's a real stinker of a problem. Or an excuse to build that engine you've been wanting but couldn't justify.

Compression loss and coolant in the cylinder are the more likely causes.

 

Im thinking the 1st thing Ill do is a compression test.
New heads I can live with. I haven't decided if she's worthy of a complete new long block.

 

Got the heads off yesterday.
Drivers side head looked normal. Normal looking plugs and minimal carbon. What I would expect a head to look like w/60-70,000.
Passenger side 4,6 and 8 had more carbon than I would have expected and plugs are pretty black. #2 dome looked the cleanest of all of the domes but has signs of some rust. I can not see any obvious signs of the head gasket leaking but I am pretty confident that it was the passenger side based on the condition of the domes compared the drivers side and the rust in #2 dome.
You can see all the honing marks in all cylinders and they look good. #2 has a small amount of vertical scratches but not to bad in my opinion. You cant feel them. It looks like 2,4 and 6 got hot. You can see between the valves were the head was starting to (melt) and #2 looks the worse. Even a tiny bit of metal flake stuck to the #2 valves.
Ill try and post some pictures.
Im thinking new head gaskets and maybe take the passenger side head to a machine shop for a once over.
Any thoughts?