Hi all, I'll try to keep this short, and really hope I explain things well enough to get some help. Heres the deal, bought a used 1990 f150 with the 300cid inline 6 engine a few weeks ago with the understanding that it needed a head gasket. finally got around to working on it this past weekend, and it is still losing anitfreeze, i believe it is getting into the oil and from there also getting burnt. Now when the truck is started it will run ok for about 5 minutes, then it begins to smoke a little, and another 10 minutes later it is smoking like crazy and the truck dies, and will not restart until it has cooled down. When I drained the oil yesterday, thinking that maybe it was just burning the coolant that was left in the oil from before I got 2 to 3 gallons of oil/coolant when I pulled the plug, and the coolant level in the radiator is still going down. Through further investigation, I discovered that the head that is on the truck now must be from an older model, as there is nowhere for the +/- 1/2 inch line (smog something i believe) that comes from the air pump to connect to the head. My question is this, Is there any difference in the heads that could be causing this problem, or do I have a warped/cracked head or cracked block? Now I know why I'm not a mechanic, get frustrated WAYYYY to easily, any comments/criticism/answers are GREATLY appreciated. Thanks, High Tech Redneck

 

Not all EFI heads have the AIR tube holes in them. IIRC, the trucks equipped with the E4OD trans did not have holes. If there is one part number that doesn't have the holes it is to some extent fair game for all the trucks, so it is more than likely the correct head. Unfortunately, these heads are known for cracking. The blocks seem pretty much bulletproof. Sounds like you've cracked a head.

 

Thanks for the info Silver Streak, I went to a junkyard yesterday and pulled the head and valve cover from a 93 F250 2wd, and after the valve cover was off my girlfriend commented how much cleaner the one from the junk yard was than the one in my shed. Think I'll still have new head checked out for warps and cracks before installing, have to wait for head bolt set to show up at parts store anyway. When I get it all reassembled I'm going to add a quart of Lucas oil stabilizer with the oil/filter change, any other additives anyone would reccomend to counter-act the effects of coolant down in the rings and on the mains and everywhere else the oil flows?

 

Don't put any additives in it, they are snake oil. There have been more things ruined by fluid additives than have ever been saved. The only additive I would recommend is BG MOA. Whether or not it will help I don't know, but it won't hurt anything.