Now, that's a wierd deal.
 

I was driving home today from Park City, on I-80, and there is a about 7 or 8 mile section of very windy, but flat canyon. Silver Creek Canyon, by name. It's actually pretty fun to drive. Maybe not in a 40+ year old truck, though. Anyway, I'm doing about 60 in ol' green, and every time it's a right-hand curve, something starts making noise. It caught me by surprise the first time. Second time I thought maybe right-side wheel bearing. Naw. Next time, it sounded more like the heater fan. Naw, fan is off. Sounds like under the hood, besides. Next curve, still heard it, but it's just can't tell. By then I'm near my exit, so I pull into the gas station to check things out. I put a finger on the wheel to see if the bearing were hot-nope, cool as can be, so I pop the hood and start looking things over and I notice that my oil filler cap is gone. (250 six w/ a big chrome oil filler cap) I figure, oh well. I'm 3 miles from home and I have another one there, so no big loss. Then I see it, sitting on the manifold behind the carb. Oh cool. I reach in and grab it. Oh hot! Really really hot! Kinda singed my fingers, it was so hot. I have no idea why it fell off. I can't remember the last time I put oil in. Probably a month ago. And I have no idea if that's what was causing the noise I heard. I can't see how it could-there's nothing there to make noise. It was just sitting there on the manifold. I think drive that canyon again tomorrow and see if it still make the noise.

Re: Now, that's a wierd deal.
 

When was the last time you CHECKED the oil, not just put oil in it? The sound may have been coming from the oil filler hole. The cap was hot due to the heat being transferred to the metal cap since it was sitting on the hot manifold.

Re: Now, that's a wierd deal.
 

Check your fan shroud, something may have come loose. So every time the truck leaned to one side the shroud may have shifted, and the fan may be zinging it ever so slightly.

Either that, get yourself a new 710 cap.

Re: Now, that's a wierd deal.
 

It uses a quart about every third tank. Yeah, I check the oil. Every so often.:lol:

The fan shroud is probably a good guess. It's not right. It's a V-thingy shroud to start with, and it's broken and loose down near the bottom. Probably why it runs a little on the hot side. It's on the list of stuff to fix, just not very high up it yet. :lol::lol::lol: