I have a 89 GTA with 5.7 and I was on my way home from college when 2 seconds I got before my house and I noticed my engine temp was almost pushing the red line. I took the turn to get into my driveway and it dropped back down to normal within seconds. Then it started climbing again so I just off the engine immidiatly. I noticed most of my coolant was dumped into the overflow tank and the oil was full. I waited for the engine to cool then filled it back up with coolant. I tried starting it but there wasn't anything but a clunk. Tried again nothing clunk, clunk, clunk. Wouldnt turn over the pistons. Does that mean the pistons froze up? Anyway I think possibly the thermostat stuck closed. Thermostat is 6 months old, water pump is 1 year old and radiator is 2 years old. Anyone have any suggestions. Or comments of how much this might be messed up? Thanks in advance.

 

Id say the coolant level was low if the temp was fluctuating. This could be due to a coolant leak, or a blown head gasket. If there was alot of coolant leaking into the cyinder(s), it could have hydrolocked the motor. Doesnt sound like it got hot enough to freeze up from overheating, but who knows.

Id try turning it over by hand with a breaker bar. If it doesnt turn, then pull all the sparkplugs. If you get any coolant out of the sparkplug holes then its likely you could have bent a rod trying to start it.

 

If the engine oil was full as in over full and the coolant was low then you are probably looking at a seriously blown head gasket. You would have a hard time turning the engine over because one or more of the cylenders have been filled with coolant. Pull the plugs and crank the engine if any spit out coolant than this is most likely your situation.

 

before i even cranked it again i'd be taking a good look at that oil!if it looks like a foamy chocolate milkshake you blew a head gasket,cracked a head or a block.time to take her down and clean/inspect everything
if the oil looks ok,change it and follow steps above.chevys are tough!they can handle getting pretty hot once in a while,could have been a heater or radiator hose.oh yeah,an intake leak at the water jacket can cause the "milkshake effect too.
Eric

 

EDIT: Oops...Already covered in the above post.

 

After troubleshooting this weekend when I was looking I noticed my block was wet in near cylinder 8. I pulled the plug and sure enough coolant come pouring out. That was the only cylinder that was hydrolocked. I was able to crank the pistons after releaving the pressure. The question is do you think it got hot enough to damage the head? I am planning on tearing it apart next weekend when I am done with finals. Will I be able to remove the head without removing the engine? I also noticed in the haynes manual it suggests removing the compressor and air conditioning unit. Has anyone else done this without having to remove a ton of accesories? Let me know what you guys think.

 

Just look around and remove what you need to get to the head. Items needing to be removed I can think of: intake, A/C (just take the belt off, disconnect at the mounting brackets, lay aside) manifold. But since you blew one gasket, I'd make a day of it and take off the front accessories (PS, A/C, alt, etc.) and lay them aside, take out the intake, and remove both heads.

Assuming nothing else is wrong with the piston/rod, I'd plan on replacing both head gaskets and intake gasket, as well as the thermostat and it's gasket. You'll want to scrape the surfaces clean, so do so with a razor blade (the kind you get that are 1.5-2" long, rectangular shape bulk packs, bigger than box cutter blades, and not angled) and scrape the surface with the edge of the blade straight down, perpendicular to the surface. Move it back and forth until you have a smooth surface (which means you go rid of the little bumps of gasket left here and there). It will probably take 3-4 blades for the whole motor/heads/intake. Then pop on your head gaskets. For the intake gasket I use "The Right Stuff" for gasket seal, and also for the thermo gasket. Run a bead (1/8" high or so, then smooth to cover gasket with your finger, you'll need a little more on fatter sections) on the bottom of the intake gasket, let it sit for 5 minutes, then put it down. Then run a bead on the top of the gasket, let it sit for 5 minutes, and then put the intake on it. Tighten it like you normally would.

It's not that hard... just takes time. Good luck.

 

finally removed both the heads and to find i blew out head gaskets on both cylinder 7 & 8. I also noticed many of the coolant ports in the head were clogged. Could this be the reason for the overheating? Anyway Im takin the heads to a machine shop to have it checked for cracks. Question concerning reinstallation of the head gasket. I have been told by a couple of gearheads that its not necessary to use head gasket sealant? Is this true. Thanks in advance.