One problem related to crankcase (pcv) has been reported for the 1999 Ford Windstar. The most recently reported issues are listed below.
I have been experiencing engine knock since I purchased the vehicle in June 1999. The first documented service at a Ford dealer was in September 1999 at 5,000 miles. The engine knock was apparent at highway acceleration speeds and on slight hills. It became worse over time. After my continued persistence at the dealer over more than a year, a TSB was found and the valve cover was replaced in the July-August 2001 timeframe per a Ford TSB (NHTSA number sb618552). This did not remedy the problem and the technician at the dealer told me in September 2001 that he still found an abnormal amount of oil in the engine. Ford engineers have suggested replacing the pcv valve and tubing system among other minor adjustments, which the technician doubts will make any difference. At this point, it appears that the valve cover redesign in the TSB does not remedy the problem. This complaint is identical to odi ids: 744509 and 725795.