Hey guys, sorry if this is in the wrong place, but I'm kind of confused. My truck (1996 4.9 F150) had been running a little rich, and threw the p0171 and p0174 codes. I just bought the truck and the PO said he had changed the head gasket, thermostat, temp sender, plugs, wires, cap it appeared, O2 sensors and other little things. It was running fine, a rough idle but great when you gave her throttle. I was in the act of trying to figure out why it was throwing the codes, cleaned MAF, cleaned TB, changed TB gasket, new PCV. Since I had it, it would puke coolant out of the reservoir sometimes after running for a while. I figured maybe he did the head gasket job wrong, but hell, she still ran, so i'd keep checking everything else out. Well, she finally had it the other night, 10 degrees out and she decides to blow the idler pulley. I knew it was risky, but had no better options being all alone and an hour and a half from anyone I knew. I made sure it was topped off with coolant and drove 8 miles to Advanced auto for a new pulley. She started to tick a little when i got there. I changed out pulleys, and a new belt. Fired up, still ticking, and i noticed she had blown all the coolant out again. I filled her up and hit the road. Nothing but cold air out of the vents, so I figured I'd be in for changing a head gasket and possibly head. She finally gave up and lost power a half hour from home. Hot, out of coolant, and wouldn't fire, but would roll over. The temp gauge inside never, since I owned it got above the normal/cold range, but she always blew hot air from the vents. I finally got it home with a tow truck and just now have pulled the head off. There was no coolant in the cylinders, and when i pulled the plugs they looked like they had gotten very hot. The hex on them looked like a torch was on them for a while. Cylinders 4, 5, and 6, had rusty looking film on plugs, i think it was Cylinder 2 that had what appeared to be some hot metal on the plug tip. Pushrods for cyl 2 looked like they had heated up more than the others. I can't find any cracks on the face of the block, or on the head itself. The gasket looks fine as well. Cylinder walls look good too. Really wondering what could have happened. Help please!!!

 

Is that a yellow body(19lb) injector I see in the bottom pick? This motor should have grey body 14lb injectors in it and obviously they should all the same.
There is also something strange going on in the left(rear?) cylinder, the exhaust valve and port appear to have been washed with coolant perhaps creating that rust pattern, and same goes for the adjacent intake valve so maybe the head is cracked.

 

I just looked at all 6, they are grey, just discolored with age. I'll probably replace them all when I rebuild it. The only rough area looks like around cylinder 2, but would that cause the whole thing to quit? A lot of rust colored residue in all of the exhaust ports. Maybe she was burning all the water into there?

 

You'd have to have it magnafluxed to detect any cracks, I wouldn't bother with that motor you ran it zero coolant toasting it. Rarely can cracks be seen with the naked eye.

Better option would be a motor from the bone yard.

 

You can often find these trucks on Craigslist for nearly nothing. Here, there are always two or three on there that are 2wd Long beds with bad transmissions but run good. Give them 500, pull the motor, sell the rear end, any good body and interior parts, fuel pumps, and keep electrical parts for spares. Scrap the rest. You will make most or more than your money back, and will be back on the road quicker than you will get your motor back from the machine shop.Attachment 132950Attachment 132951

 

True enough. That's how I got this one, $650 on CL. I have the motor and tranny from my old 86 still available too. I was looking into swapping it into this good body and frame, but the EFI truck to a carb'd motor looks a little tricky. The junk yard down the road has a head for $65. Would it be worth a try and see if the motor is still healthy enough? Any thoughts on the carb'd swap?

 

300's are tuff as hell, but no one can promise you there is no damage to that block after heating it the way you did. That $65 gamble and labor is up to you. The 300 seems to be a motor that was actually better as a carbed motor even with a properly running efi. But, there's no way I'm ever going back to a carb on a daily driver on anything. Run out at 5am in 5* weather, crank it no problem with out even getting in and run inside and let it warm up for 20 minutes while you eat a bowl of cereal.