Thanks to all !

I simply want to thank you all. I had problems when it was time to start the engine 30 minutes after I stopped it.... It was air intrusion.

I'm not a mech, just a computer technician but explanations in many threads teached me what to check, what to do and now, air intrusion in my 1991 7.3 idi is away.

(I still have probably air intrusion from schrader valve but I will order part as soon as I find the part number).

Thanks again !