So, our F250 project truck just finished it's usefulness for the year (we took it to Burning Man, and now it's back). I was hoping to spend the year doing some maintenance on her. Every fluid leaks from the damn thing. Oil from the oil pan and valve covers, coolant from the freeze plugs, and now tranny fluid from somewhere. I think it is time to pull the engine and do some work on it.

I've never pulled an engine before, and none of my friends have either. Basically we'll be using our common sense and the Chilton's manual.

I am hoping to pull the engine, and replace some seals and gaskets. Things like the rear seal and the oil pan gasket, that seem to be prone to leaking.

Should I take this opportunity to open up the engine, replace piston rings and bearings? How much more money/work will that require? Basically, am I looking at 1000's of $ or 100's.

Thanks guys.

 

From what it sounds like you use the truck for, I wouldn't reccomend a full blown rebuild unless there is something wrong with how it is running (knocking, ticking, etc...) If it's just leaking fluids, most of the gaskets and seals can be replaced without pulling the motor from the truck. The only reason I would pull a motor out would be if I were replacing internals, such as rods and pistons.

 

How do I replace the rear seal, oil pan gasket, and freeze plugs without pulling the engine?

 

I've never had to replace a rear main seal before, but I don't see why it can't be done with the engine still in the truck. I've replaced an oil pan gasket and freeze plugs on my old 64 Nova with the motor still in the car, and if you know anything about those old Novas, you know that they have a tiny engine compartment (especially with a V8). It may take some creative maneuvering, but it'll be way easier than pulling the entire engine out of the truck to replace a few gaskets.

 

I would pull the engine and do a complete gasket set, and inspect everything else in the process. You can take the whole front clip off, 10 bolts I believe, for real easy access. It's not that big of deal on these trucks.

 

Plus, you would probably waste that amount of time trying to figure out how to do it in the truck. It is just hard to get everything right when you can't access good.

 

I would check the compression. If it's still OK, I would just change the gaskets and seals. To change the real seal you will have to drop the tranny. Chilton will address everything in there.

If your compression is unacceptable I would pull the engine and do a rebuild. It may cost you a couple thousand depending on the the needed machining, tools and parts.

 

What engine is this you are talking about ?

I would pull it and do it right the first time.

Getting freeze plugs out with engine in is possible but you have to have to be a contortionist to do it.

 

My 2 cents. You shouldn't have to drop the trans to change the rear main. All of the oil leaks that you've described can be changed with the engine in the truck, not sure on the freeze plugs though? Someone in here will know.

BTW info such as what engine, trans, 4x4, 4x2, etc are almost a must to determine what needs to be done.

 

It's a '79 F250 2WD with a 351M (originally a 460, but it's long gone). I think I'm just going to pull the engine and be done with it. It might be fun to mount it on a stand and paint it as well. I'm not just looking to minimize work, I'm also hoping to learn a bit more about engines. This truck is a complete toy, and having it out of commission for a few months (even half a year) is absolutely no problem. But, on the same hand, I don't want to step into an expensive quagmire of replacing parts.

My transmission has developed a leak after a long drive, and it might be worthwhile to pull it anyway as well.

The compression was measured to be about 100-120psi on all cylinders, when I checked 6 months ago.

I get the impression that if I pull the engine, change the valve gaskets, head gasket, the front and rear seals, and the freeze plugs, I won't end up spending an arm and a leg. I can buy a used engine stand and sell it when I'm done. I can also borrow an engine hoist for a couple of days. As long as I label all of the wires and vacuum tubes, I think I can avoid any huge problems. I'm going to go read the Chilton's manual a few times on the procedure, and make sure I don't make any dumb mistakes.

Are there any common mistakes that I should avoid while pulling the engine? Anything else I should check while it's out?

Thanks for the advice, guys.

Oh, the VIN says it's a C6 tranny, but I don't know if that's been swapped too.

 

Nothing wrong with trying to gain knowledge. If that's what your after, and you have the time, go for it!!! There's nothing better than hands on.

These old trucks are pretty simple, I cant think of anything off hand to watch out for or check.

 

If it was me I wouldn't put a dime into a high mileage 351M.

Find a great condition 400 and put that back in instead

about Same mileage with more torque. You can increase the HP & torque by building it or bolting on parts .......and increase the oiling performance by making the necessary improvements on it while on the stand.

 

The simplest way is to get a low milage used motor. I agree with Mr.Mil1ion that the 351M is not a desirable engine. the 400 or change to a 429-460. get a good runner,give it TLC like change the soft plugs,maybe a windage tray,gaskets ect.,while your driving your old motor. I go this way because its a time saver and you don't have a dead truck growing moss.

 

Unfortunately, engines cost money. I'm pretty poor right now, and I don't have a couple grand to drop into a new engine. And I'm in Pasadena. I simply don't have room to store stuff. It's cheap enough to buy an older vehicle and rip out it's engine, but I simply just don't have room. Not until I sell one of my vehicles (and I love them all).

Thanks for the advice guys. It sucks when I simply cannot follow good advice, but sometimes that's what happens.

 

I would pull it and spend a dollar now. If you don't and you get a leak in the middle of nowhere and the engine blows what is it going to cost you then. As far as the money is concerned, I'm in the same boat. I am in the process of buying a 77 150 4x4 auto and have to do it over time cause of the lack of funds. I don't know the wait of the engine and tranny or your location, but if you are near a Harbor Freight Store they sell 2 ton hoists for 149.99 and 19.99 for a load leveler and 1000 lb capacity engine stands for 39.99. I would think that seeing how we weekend machanics don't do this stuff day in and day out these tools are good enough for or use. As far as the tranny goes if it is a c6 you could not get a easier tranny to work on. Good luck acc2828