Freestar Oil Pump 0-ring
 

The oil pump on my 2006 3.9 liter Freestar needs a new oil pump o-ring to stop an oil leak. Is Ford the only place to buy it? Any idea of the price from Ford?

I bought the whole bottom end gasket set at eBay. Lower Gasket Set Fits 99-07 Ford Windstar Mustang 3.8L 3.9L 4.2L OHV 232 238 256. Cost 20 and some change

Oil pump o-ring
 

I ended up buying it from Ford, but I bought it online. I still payed more than $20 like you did. However, I got my Freestar jacked up and when I was taking a look at how much "fun" it was going to be to change the Oring, I noticed that it wasn't leaking anymore. I had Valvoline synthetic oil in it. It was time for a change, so I put in the Motorcraft blended oil which is what I usually use and it stayed dry. Now I've got the synthetic oil back in and things are still fine. When it was leaking, my garage floor had good sized drops on it, but now it's dry again. If it comes back, I'll change the Oring

Some guys get all the luck. It was a fun 90 minutes of work ended up dropping the water pump tube which also required a new o ring. I wonder is synthetic thicker causing yours to stop leaking for a minute or did the luck just give way?

No, it's all 5W-20. I usually use Motorcraft blended oil, but Menard's had a good sale on synthetic Valvoline that also had a good rebate. The oil leak started the first time I used the Valvoline synthetic. Then I switched back to Motorcraft blended after I saw that the leak had mostly stopped. It completely stopped with the Motorcraft, so I tried another change of full synthetic and things are still fine. It's been about 3,000 miles since I last changed the oil. Only 90 minutes? That's quicker than it looked like it'd take. Good work.