I'm looking to buy an OBS F150 with a total budget of around 5000$. Most trucks in my area cost around 3500$ with 100-150k miles. With about 1000$ to spend on parts, what would you all recommend I put into the truck as far as comfort upgrades and preventative maintenance? I want something that is super reliable so I don't care too much about off-road capability or looks.
Are there any specific weak points that should be replaced on the 300 or 302? (351 is too much of a gas hog for me)
Are the OBS trucks prone to failure in fuel pump, water pump, oil pump, injectors, radiator etc...?
I don't have my eyes set on a specific configuration yet. I'll just buy whatever is in the best shape for the best price.
Thanks!

 

I think most would argue that the 300 inline 6 is the most reliable motor available in these trucks, even if it is the least powerful. These will regularly last 300k miles. Around here, the body usually rots off the truck before these motors quit running. A 5 speed or E4OD is also probably the most reliable choice of transmission. In a regular cab, 2 wheel drive pick-up, you should easily see high teens for fuel economy. If you drive the truck nice, 20 MPG is easily attainable. Fuel economy with the 302 is not much different than this. Many people reporting 20 MPG on lighter trucks. The 351w can get mid teens (16 is probably average, respectable even by comparison to today's engines). With that said, I have also seen numerous 302s and 351w's with 300k+ miles, but this doesn't fit the 'legend of the "Big Six'". In all honesty, any three of these motors are very reliable. By the time they were put into OBS Ford trucks, the designs of the "small block Ford" and I6 had been tried, tested, proven, and improved for the better part of 25 years, with more improvements made to the designs throughout the production of the OBS trucks.

Mechanically throughout the the 3 engine choices, they are all very sound. The only real wear point on the 302 and 351w is the timing chain (300 has timing gears). This will stretch and can cause issue if it were to skip a tooth from slack. This is typically good for 70k-100k miles and is easily replaced. Water pumps last quite a long time. I typically end up changing them when I do the timing chain on the V8s, since they are fairly cheap. The oil pumps can last 300k+. The only earlier failures I have seen were after somebody gooped silicone all over the gaskets and it worked it's way into the pick-up in the oil pan and started the pump for oil. The earlier trucks have a module on the distributor that was somewhat problematic and would cause loss of spark when the module overheats. This was moved to the fender during the 92-96 run which mostly solved the issue. Late model trucks also had OBD2, and could be had with MAF, which is a big plus in my opinion. Fuel pumps are hit and miss. The 87-91 trucks use a low pressure lift pump in the tank (if you have dual tanks, 1 in each tank), and a high pressure pump on the frame rail. They went to high pressure pumps in the tank for the 92-96/7 trucks. Much better system, and seems to be much less issue with the pumps back feeding the other tank with this set-up in my experience. I know you said you weren't considering the 351w, but just for the sake of information, in '94 they switched to a roller cam which made a little more power and is arguably more reliable.

Some of the parts prone to failure are the selector valves for the trucks with dual fuel tanks causing one tank to fill the other tank, and the 2G alternators were also prone to failure and the occasional fire in the earlier trucks. Later OBS trucks moved to a 3G alternator, which was a big improvement as it has an increased output and did away with the fire issues.

In my opinion, if I was looking for one to use as a dependable daily driver, I would likely go with a later model (95-96) 302 or 351w powered truck with an E4OD or 5 speed. You'd get OBD2, air bags, and should be able to find a truck with MAF (which will help fuel economy and power).

 

Thank you! How do I know if he truck has the E4OD? And is the other auto transmission the 4R70?

 

Transmission code on the door jamb will be E for an E4OD. The 4R70W was problematic in the early years, but yet, that will be another option.

 

Appreciate it!

 

Before you make a purchase, run diagnostic codes and see what or if anything is going on. If you get no codes, drive it till at least operating temp and run the codes. They may have been cleared on purpose. Here is how you run diagnostic codes. Sandy