I have a 1987 just had new rear main seal replaced. It will run perfect for 5-10 min then die and won't restart

 

Hello Julecodd and welcome to FTE.

You've posted your plea for help in the 1999-2014 Super Duty forum. While we are a helpful bunch, you may get better results if you post your request in the 1987 - 1996 F150 & Larger F-Series Trucks forum. There may be a few other forums on this site that can assist you, but we'll get to that shortly.

But, as I stated, we are a very helpful bunch of members. What we are lacking is information. You have a 1987 F-250. You replaced the rear main seal, now the truck runs for 10 minutes and then dies?

What engine do you have? 302? 300? 351? 460? 6.9L IDI?
What transmission? AUtomatic? Manual?
2 wheel drive or 4 wheel drive?

When you say it runs for 10 minutes then dies, can you expand on this? Does it idle, or can you drive it down the road? Does it die like someone turned the key off or does it sputter to a halt? How do you get it started again?

What rear main seal was replaced? (engine? transmission? Johnson rod?) I can guess this seal was replaced because it was leaking?

Once we have these questions answered, we can help you determine the issue. As I stated earlier, you may also want to post in the engine forum, but I can't tell you which one because I don't know what engine you have.

 

Thanks the engine Is v8 5.0L it is a manual transmission , 4WD, the rear main seal was on the engine it was leaking. After driving it and it runs good it begins to sputter then dies. It will sit and idle for a long time. The fuel filter was replaced. My son said he hears the fuel pump kicking on. Cannot restart it for an hour r so .

 

My old Bronco II did similar things. It was the in-tank fuel pump overheating (probably the original pump, with almost 250k on it).

I replaced the frame pump and the in-tank pump and it fixed the issue. Not too difficult of a job, and not too expensive.