I just had to put a water pump on my 1986 F-150 ..last week...It's got 166.000 miles on it..I don't uselly don't drive over 3-5 miles a day..just over the hill down to town to work and back..but drove farther the other day to put new doors in a house..probably 10 miles eachway..when i got back home i noticed..white gray smoke coming out the exhaust..let it cool and checked water level in rad....took about a qt...to bring it back up top..have been noticeing that any water in resovor(sp) tank has been disapering..for about 6 months..I'm thinking head gasket..but thats not going to be a easyfix..I don't think the blue wrench would get the exhaust manifold off without alot of trouble..Talked with my neighbor who works as a GM mechanic..he told me not to tear it down..to put in K-Seal by Solv-Tec..he just stopped by and handed me a bottle..free....said alot of dealers are useing this product..for repairs... http://www.kseal.com/ Any of you guys used or heard of this .. I did a google search..and found none that said it didn't work..