DISASTER: 1998 Grand Am with 3.1 Overheated

[LeadBasedPaint]

Folks, this is one of the hugest disasters I've had with any car - - even considering the FORD that I had.

I had this little radiator leak problem so I patched up the plastic with some Quick Steel from AutoZone. Mine was leaking in the plastic part on the side near the battery. Well, that stuff worked great!!! My car was performing awesomely... Until last night after my boy's soccer practice.

I had just gotten on the interstate and I saw that the temp was way high. I'm not sure, but I think the light came on, but I'm not sure. Anyways, I sat and let the thing cool down. It would turn over, but it was sluggish as if the battery were low. But it started and I started driving again. The FUNNIEST thing happened: the temperature gauge started going down. I said, "Great. Must have been a freak problem." HA HA HA HA HA HA HA HA HA!!

I was cruising along and all of a sudden the engine started knocking really bad. It wasn't to far to the next exit, so I switched the engine off and coasted down the of-ramp.

Dudes, this thing was hot. Smoke was coming in through the air conditioning vents.

You're probably thinking that I was pretty pi$$ed about the ordeal, but you're wrong: I've been left stranded by this piece of junk more times than I'd care to admit, so I'm pretty much used to it.

So anyway, I got it to a parking lot (yes it started again) so it would be off the road. This morning, the engine won't turn over at all. I hear like a whistling sound along with the "click" so I'm not sure what that is.

What else.... Oh yes. I put coolant in the reservoir but the level goes down very quickly. I don't see any coolant on the ground below.

So... probably a seized engine. This is the second one of these engines I've put in the car so I'm just a wee bit discouraged about doing this again.

1) What do y'all think is wrong?
2) Is there a different engine that might fit in this piece of crap car I've got?

V6 Grand Am 3.1 (3100) engine, 1998 SE

[sunrunner_pei]

Wow. Yeah, it seems as that you've done major damage. The 3400 will swap in with some additional work, but may be worth it. Then again, on a 10+ year-old car, it's hard to imagine spending a whole lot on it. Check http://www.3400swap.com for swap instructions.

[LeadBasedPaint]

Is the 3400 any better? It's got beaucoup miles on it, but I think that replacing the engine might be less expensive than buying a new car... maybe. I'm a bit tight on cash right now.

Any pointers on verifying whether it's actually seized or not?

[sunrunner_pei]

The 3400 is the same basic design and shares many of the same faults. Particularly, like all GM 60* V6 engines, it's prone to having the Lower Intake Manifold gasket leak. But the 3400 is newer, more abundant, and more powerful than the 3100 it replaced. It won't be a perfect straight swap, but it's pretty close.

[AznGA]

3400 is basically the same design as 3100, except being more powerful.

[Shadow-D]

Get a breaker bar and try turning the motor over by hand, if it will not budge then it's most likely seizes. It could be heat seizes. You might be able to put some lubricant into each cylinder and try to break it free. I wouldn't trust it for too long if you are able to get it free. The biggest question is why did it overheat in the first place? Have you heard any kind of knocking or ticking that was out of the ordinary?

[rixGAphx]

You lost all coolant (possibly from the radiator repair blowing loose, mebbe from a rad hose or other major leak).
For several miles the waterpump was just pushing AIR through the coolant passages; only Porsche and Corvair (plus Continental and a few other aircraft engines) have ever had successful air-cooled 6-cylinder engines.
The temperature sensor doesn't read air temp very well, so the baking air (at 300*F +) wasn't causing the gage to read high until all hell had broken loose.
It wasn't reading sir temp, but rather metal temp conducted through it's threads.

After the metals cooled-down (the first pull-over) the gage dropped because it didn't have hot liquid to read.

Head temps in particular were soaring (with exhaust gases going though the exhaust runner), and oil from the pushrods was dribbling thru the valve area, removing some of the heat but also baking itself onto the aluminum.

The pistons were being cooled somewhat by splash oil hitting their underskirts.

Eventually, the metals get so hot that the pistons swelled in their bores and caused too much friction, the air-fuel mixture got so hot that it pre-ignited at about 7:1 compression ratio (when the pistons are still going way UP) and the oil cooked so that it no longer functioned as good oil with long molecules.

Oh, and the aluminum heads were RED HOT at the exhaust valves, and the rest of the head got hot enough (prolly 500+ *F) that it warped.
This has 'blown' the headgasket at one location (at least), causing the slight 'whistle' sound as air escapes when the piston s-l-o-w-l-y rises and pushes air out.
So you aren't 'seized' as such, but those aluminum pistons are no longer round and their oval shape is pressing tightly to the [mostly] still-round iron bores.

Repair will require new heads, block re-bore, and new pistons/rings/bearings at the least.
The iron block is damned-near indestructible, but there's a good chance the bores aren't all round, and a slight chance it has cracked; machine shop magnafluxing will find cracks, and boring (mebbe just honing) will restore the cylinders.
The conrods, crank, cam, and valve train are likely all still fine.

Your best bet IMO is a j/y 3400 with under 60k miles, with a LIM gasket repair before you install it.