Leaking Ford 7.3L Oil Cooler Seals and Gaskets @ 374k
I parked my F250 in our attached garage last winter, which means I rarely had to start it in cold conditions. The garage has insulated doors and rarely drops below 45-50F.
I began restoring my 1950’s Chevy truck this summer and it currently lives in the garage. Now that I’ve begun cleaning up and/or replacing many mechanical items, I hate the though of parking it outside if I can avoid it. That means the F250 is going to see a lot of cold starts this winter, unless we decide to move to a house with a larger garage or build a shop in the near future (both are unlikely). As a result of the cold starts, I am beginning to have several issues with old/brittle seals and gaskets failing on my 2002 Ford 7.3L PSD.
One of our first cold mornings of the year was 10/26/2012. I started the F250 and immediately moved it to the end of the driveway to warm up so that it would not be in the way while moving some things in and out of the garage. The 7.3L PSD left an 8″ to 10″ pool of oil at the end of the driveway after warming up for about 5-10 minutes. There was no spill where the truck had been parked overnight. The engine stopped leaking after it was warmed up. I immediately soaked up the oil with rags and then thought to take a picture showing the size of the spill (see below). We had a very strong north wind (blowing from right to left).
I was unable to determine the source of the oil leak. My mechanic couldn’t tell either because there was such a huge mess of oil on the underside of the truck. He had me add dye to the motor oil around 11/12 and come back a few days later. He was able to confirm the leak was coming from the oil cooler on 11/15 and determined that we could replace all of the (expensive) seals and gaskets for around $200 (parts) compared to replacing the entire oil cooler for around $1000 (parts). I believe there were 4 seals and 1 or 2 gaskets. He showed me how brittle the old seals were afterwards. When you bent them, they just cracked apart! The work was completed on 11/19/2012. I have had several cold starts since the repair, without any oil leaks!
The following pages describe the same issue I was having and these people seemed to perform the same repairs:
http://www.dieselbombers.com/ford-powerstroke-99-03-7-3l/62581-oil-cooler-leak.html