THis is my first post and I hope somebody will have some feedback. I was towing a small boat at 60mph and my engine overheated. I pulled over and it shut off then 2 minutes later it blew the upper hose out of the radiator breaking the plastic fitting. I've replaced the radiator with a new one, but in doing so I pinched slightly the upper radiator cooling line so it now has reduced flow capacity. Anyway, now when I drive the truck it sounds and acts fine at lower rpm's but just before it shifts into the next gear I hear a loud and fast clacking sound (like a diesel engine) then after the shift it sounds smooth until rpm's increase again. When I drive 40+ mph the sound is constant. Also, when I let off the gas I hear the sound for a few seconds as the rpm's drop. My oil is very dirty looking, but I just had the rear main seal and the oil pan seal replaced 2 days ago so the oil was new and clean before the overheat. Did I blow my engine??? Please help. I'm going to change the oil and filter...my transmission fluid is at a good level (checked hot w/engine in park) Radiator now seems full, I've constantly checked and added fluid since the new radiator.

 

I'm not sure I'd have much mechanical help, but the first thing I'd do is flush all the fluids out. change everything that might've been affected by the overheat. just as a precautionary measure, if anything got really dirty, seafoam is almost divine. good luck, sounds like a really unique situation.

 

I had a 88 or 89 Bronco that I had over heat really bad one time and I broke a vavle spring. It never did really affect the power or anything but it did make a noise.

 

Did it over heat to the point that it died? this is very bad could be bottom end making that noise ,or timing chain those 300"s are tuff but heat can do major damage to any engine. GOOD LUCK

 

There is no timing chain on a 300, it's gear driven. What color is your oil? Is it a light chocolate milk color? You could have damaged the head/head gasket when you over-heated

 

Thanks to all! I realized there was no timing chain, and I believe you're right about the head gasket. The oil IS milky, and the sound is less right after an oil change, but within a few miles of driving the sound comes back. I tried some sort of copper seal product from an auto parts store in my radiator, but to no avail...still clanks. I suppose the only option is replacing the head gasket. Anyone know what the chances of reviving this engine are????

 

The head gasket is really not that hard, I had the lucky chance of trying my sister's car this last weekend. '92 pontiac grand prix, engine in sideways. That's all I have to say.... But we got it done, it turned out to be a broken head bolt. Anyway...Just get yourself a chilton manual, and make sure you label all of the connectors and vacuum hoses. Also, take pictures before you start, so if you have any question on how it goes back together, just bring up the pictures. When you get the head off, take it down to a machine shop and have it looked at. Good luck.

 

I brought it to a mechanic friend and he said it's a bent rod or broken wrist pin... I'm buying a newer truck. I need a truck that will tow a 1500 lb boat with 2000 lbs of oysters...any suggestions?