Lost fan belt and overheated engine bad
 

Took my girlfriends son for a ride in my Firebird and got on it pretty good a few times. At some point the fan belt rolled off the pulleys. We pulled into the drive way with it at about 230 degrees. I left it running to go in and grab the keys for hood with the teenager watching it as my car would cool down idling. When I got back outside it was starting to smoke out the hood so I ran over to shut it down and when I looked at the gauge it was just beyond pegged. I am guessing 300 degrees.

I let the engine cool down while I reinstalled the belt and checked the oil for antifreeze and water. About 10 minutes tops and it was down to 210 degrees. I fired it back up and there were no strange sounds from the engine. I kept it at about 1,200 RPMs for a minute or two and it cooled down to 190.

I have looked into the radiator and do not see any oil. I don’t have any blow by out of the valve covers. I am going to change the oil this weekend.

What do you all think? Should I pull the engine or chance it?

I think you're fine . It was a short time with no load on it..

Most likely you're ok. Check the oil to make sure no water in it. If it doesnt miss when it running then i'd say youre good.

Theoretically:
Headgaskets relaxed a little.
Exhaust Springs relaxed a little.
Moisture cooked-out.
Valve cover gaskets cooked.
Timing Cover gasket, Water Pump Gaskets, Thermo HSG gasket relaxed.

Actually, Reality:
I would run a wrench along al the mentioned FLUID gaskets.
Drive it. Think happy thoughts, and question the mechanical Fan going clutched, smaller, or Electric. Or leave it.

I'm pretty sure you'll be fine also. You never mentioned that the radiator was spewing fluid from the overflow. I doubt it was at 300 degrees. It would have probably stalled before that. You'll be fine. Drive it.

In racing stock cars this happens frequently, because it's not like diving on the street, or drag strip. The cooling system is run to the max all the time, and any small problem shows up immediately.

I've overheated my cars much worse than you did, and the areas that may show damage are frequently piston, cylinder bore, and ring damage, because your swelling them in the bore and increasing the drag on the piston and rings. If you damaged either badly, it will show up when you resume driving it normally. I've also gotten the engine so hot that the decks of the forged pistons deformed, and one completely collapsed with a hole through it. From your description, you never even got close to that point. Forged pistons usually tolerate overheating better than cast pistons do.

There is no doubt that you took some life off the engine parts, but if you have no increased blow by in the crankcase you probably dodged a bullet. Every incident of overheating will loose some ring tension, and the ability for the rings to seal against the cylinder wall. If you want to do a compression test, or a leakdown test, it may show any deviation for one particular cylinder. If you have fairly balanced results within normal range you're probably going to be fine from this point forward.

If you have some low cylinders with either test, a bore scope would probably reveal and damage within the suspected cylinder.

Get that oil out of there immediately, it may have gotten hot enough to change the molecular structure, and lost it's ability to lubricate the internal parts properly.

If you run into this problem again, you can flood the outside of the radiator with water from a hose, or bucket to bring the temp down quickly. However with the fan belt off your not going to be able to use that method until the fan is spinning. Frequently used method after the cars come off the track to bring the temp down and let the tension come back to the fasteners, and other parts under tension.

I hope some of this info helps you.............;) Good luck with the results.

Lots of good information above to read and follow. Assuming you had a 15 lb. radiator cap, and you reported no fluid loss or belching of coolant into a overflow tank, the cooling system did not reach 300 degrees F.. Here is why. Maximum boil protection with antifreeze is 226 degrees F. You add 3 degrees per lb of radiator pressure held. 15 lbs. equals 45 degrees. So you will begin belching fluid out of the radiator at 272 degrees F. If you were losing no fluid, you were likely in the 250-260 degree zone. That's plenty hot but probably not fatal to the engine. As mentioned, some damage probably happened, but it hopefully is very minor and not noticed. Small leaks of oil and/or water will be the most likely noticed items. Hope it's OK.

Thank you everyone for your input. It was steaming and the catch bottle is a JAZ bottle like this. It did fill it up. I will check everything over real well and see if I can find anything amiss.

Your input helps tremendously. I will change the oil immediately as that is my thought as well. I was ready to do the water hose over the radiator trick, but I thought that it might be better to let it all the metal grain structure realign naturally. I also had to get the belt back on and the temperature dropped rapidly.

One spare part I've always carried is an Alternator belt. I've loaned it out at the track 2 or 3 times now.

yep I would change oil and filter make sure there is no leaks or drips around any hose clamps and adjust as needed.

I always carried a spare Alternator Belt and Power Steering Belt, the Trunk is empty and the parts take up so little room and cost basically nothing.

But eventually everyone learns: (things so wrong, parts fail for a variety reasons, always carry spare parts that can get you back home and the tools to install them.

I agree that there might be some engine damage to the engine.
A Compression/Leak-down Test would tell you a lot and just takes a afternoon of time to get the results.

Tom V.

I had engines before that overheated and lost some oil pressure because the oil broke down some . I've you've had any of that, would not be a bad idea to change oil.

Thanks guys. I am changing the oil and then I will do a compression and leak down test.