Bad head gasket and broken head bolt

I took the head off the truck today (1991 f250 300-6) to see why it was overheating and one of the head bolts was broken (that's where the head gasket failed too). Looks like it was broken for a while. The part of the bolt in the head was rusted in pretty good, but did come out. I will try to remove the piece in the block tomorrow. Everything else looks ok after a quick once-over. I have a new gasket coming tomorrow and will have to locate a new set of head bolts. I'm not sure why it snapped, but my only thought is someone over tightened them and broke it or it broke soon after. I got the truck years ago as "scrap" and was told I should drive it to the scrap yard. I fixed it up a little and have been using the heck out of it for over 10 years. Maybe the guy knew the bolt was broken? Is that why the valve cover bolts were loose? I don't know.

I am amazed the truck ran like this for as long as it did. I have pulled 20k lb trailers and hauled beds full of firewood with a bad head gasket and broken head bolt! It has been overheating randomly since I got it, but I figured it was just low coolant from the small radiator leak for the first few years and just kept it topped off. I swapped radiators and that one started leaking too after a few years. Now I know why.

We'll see how tomorrow goes and play it by ear. We have a few blocks/heads/engines sitting around, so it's not a lost cause if the head or block turn out to be bad. I have a different transmission to swap in anyway, so pulling the block wouldn't take very long.

I'm hoping to have the truck up and running in the next week so I can get more firewood and plow any snow we might get. (We've had plenty of snow)

 

After owning a 93 f150 with the 300I6, I was a believer. Those are simple, easy to work on engines. Good luck with the repair! As you know, they are great firewood haulers.

 

I hope the bolt in the block is flush, or close enough, so you can weld a nut to it and turn it out.

 

This was my thought.

tag a nut to that is what usually lets you get the bolt out.

 

I'm still baffled why they quit making them..

 

To reliable = not enough sales because they last forever. ( just a guess)

 

Because of emissions and cafe

 

Yes, the bolt sticks up just a little, so I can clean it and weld on a nut. I'm going to stick a nut in the lathe and remove the threads and taper the inside so I can get a better weld. My plan is to let it cool, then heat the block a little and use some oil while turning on it. I'm hoping it comes right out. I ordered more parts this morning and they will be in around noon.

As far as production of the 300-6, I have heard from a few old ford employees that they were working with a crossflow head and turbo setup before scrapping it all and moving on. The engine itself is just pistons in a block, and that doesn't mean diddly for emissions. It's the head design and air/fuel management that control emissions. Emissions was just their excuse to scrap a very reliable engine and move on to something with higher hp numbers (I rarely run mine above 2500 rpm because it has low end torque). I really want to switch to an aftermarket ecu for better tuning and fuel management, but that can wait. I just need the truck running again.

 

I drove my friend's late 80s F150 with that motor. Not the most advanced technology but it drove great and had plenty of torque. Basically a funny sounding v8.

 

This ↑

 

I like inline 6 cylinders. I've had a Ford 300 but my favorite was the 4.0 in both my TJ Wranglers.

 

One of the best engines Ford ever made in my opinion. I'm still working one in my 89 F150. I ran a 91 until the frame broke but the engine was still strong. Built the 89 out of a mix of parts from it and the 91.

 

I had a 200 six in a Ford Falcon. I pulled the head to do a valve job. When it came time to put it back together my back went out. A buddy helped me lift the head back on and torqued everything. The idiot broke a head bolt. Oh well ran it anyway. Engine did another five years in that car and I scrapped the car and sold the engine.

 

You cannot kill an ford inline 300, they can only be murdered. I changed the head gasket on mine at 300,000 miles and just about every other gasket. Exhaust side in between cylinder 5 and 6 blew out. I shut it down before it overheated. Had the head milled and she's still going strong. I think the head is almost 90lb.

I had the same engine in my Deere 4010.

 

I forgot about the 200. I had a 74 bronco with one. Had an offenhauser cam in it.

 

Inline 6 is just a great engine design, gas or diesel... there's a reason that most semis have inline 6 engines...

 

I got the broken head bolt out. I tried twisting it with a vice grip, but it wouldn't budge. I turned a nut in the lathe so it was tapered inside and no threads. I ground the top of the bolt for a clean welding surface, set a washer over it, then the nut and welded it on. Let it cool for a few minutes, heated the block, gave it a wiggle with a wrench and it came right out. Textbook removal, which I greatly appreciate. I scraped the head and block and checked for flat. The head is .002-.003, but well within service limits, so it's going together. The block is good to go. The valves leak a little air, so I'm going to check them out tomorrow. Hopefully they can be lapped and seal up. I covered everything for the night and will get parts in the morning. The valve stem seals won't be here until tomorrow anyway, so I figured I'd make the most of today and get it cleaned up.

 

My buddy has a saying about that....
6 in a row, ready to tow, 8 in a V, squats to pee. He's a diesel mechanic lol.

 

Didn’t Ford run a version of that engine in equipment as well? I want to say older chippers used an inline 6.