Hey guys, this question relates to a '74 Firebird with a 400, not specifically a thirdgen. But I'm kinda desperate for some advice.

I was driving my firebird home and apparently due to a leak in the water pump, the engine ran out of coolant. The car started shaking very violently which I assume was ping, caused by the car running WAY too hot. As soon as I realized what was going on (which unofrutnately was not as quick as I would have liked), I turned the car off and coasted down to the bottom of the hill I was on and had the car towed to my house.

My question of you guys is, how do I tell if the engine is destroyed? I have heard that ping/knock is the death of any engine, and the car was pinging quite violently. Tommorrow I can fill the thing with coolant and drive it around to see if the engine shakes and feels completely out of whack, but is there anything in specific I should look for? It would be a shame to scrap such a wonderful car, but I'd also hate to replace the water pump and put so much effort into the car to find out that it was destroyed. Any advice would be REALLY helpful right now as I am a little panicked.

-- Henry

 

fill it with water and see how it runs. it ought to be ok. about the worse damage you'd find is warped heads or leaking head gasket. if it runs good fix the leak, if not might want to investagate a little more, leak it down, compression test, preasure test cooling system.

 

Oh, so we're your last resort, eh?

Your engine is trashed, and the car has probably suffered irreparable damage, so you might as well just park it on a trailer and ship it to me...

Seriously, the old Pontiac V-8 cases are so massive and stable that I doubt you did any damage at all. Follow Ed's advice, and when you replace the water pump check the replacement very carefully. Pontiac had several impeller sizes, and you want the deepest vanes you can find. If you compare the impeller to the pump you remove, you want at least that much vane, no less, or you could be looking at overheating again.

Or if you're tired of it, you could still ship it to me....

 

I overheated 305 really bad one time. Didn't notice the coolant leaked out till it was knocking really bad and didn't have any power.
I thought for sure the bottom end was history. It sounded terrible.
When the wrecker showed up, we fixed the busted hose and started it up. As soon as the eng fired, the wrecker guy poured a quart of auto trans fluid down the carb while holding it at abt 2500 RPMs. He said most likely, the oil had burned itself off the cyl walls and the tranny fluid would help lube the rings to prevent ring sticking.
He poured it in at a pretty aggressive rate. Just not quite fast enough to kill the eng. He said the "loud knocking" and loss of power was probably from the hyd lifters pumping down since the oil was so thin at those temps.
Once the smoke settled, I got back on the highway drove it another 150 miles home. That eng went another 50K miles with no problems.