Coolant leak

[h2005frank]

Folks I am new to this forum. I have a 70 c-10 250 inline 6 which is original to the truck. Had the truck forty years. truck has run great all those years. Engine has never been apart. Recently I have noticed coolant seeping around cylinder head bolt #1 according to tightening sequence. Can't tell how many if any are leaking under valve cover. Did a cylinder leak test and pressure test on cooling system. Did not come up with definitive answer. I tried taking that bolt out to clean, chase, and seal threads with permatex 59214, did not help. Also tried permatex aviation form-a-gasket liquid seal on that same bolt and it's still seeping. If my health was better I would just start taking it apart till problem was found. May be too big of a problem for me to take on depending on what's wrong. Could someone with experience on inline 6's give me some direction?