I have a 1985 Ford F-150 XLT Lariat Short Bed 4x4 with a 302 and a granny 4 speed transmission. When my truck warms up on idle it blows bluish white smoke outta the exhaust. When I rev my truck up the smoke get's worse. Does any one know why? or How? to fix this problem?

 

Kyle - blue smoke is oil being burnt. Most likely your rings and/or valve guides are worn.

If you go down a long hill then floor it at the bottom, do you get blue smoke from the exhaust?

The reason that it's happening more at warm-up (or going downhill) is that with the throttle nearly closed, vacuum is high in the manifold so oil gets sucked up past the rings into the cylinders......or down the valve guides if they are worn.

 

Ken, It only does it when it's idling it doesn't do it when I drive it. When the truck is moving down the road there is no smoke at all.

 

It may just be the valve stem seals then.

Have you had a compression test done? That will give an indication of the condition of the rings & bore.

 

If you have a catalytic converter on your truck, and it almost for sure came with one from the factory, after it gets warmed up it will "eat" the smoke. So, while you may only be seeing it while warming up that doesn't mean it isn't smoking at other times.

 

If the truck only blows blue smoke when it first starts, that is usually an indication that the valve seals are worn to the point that when the truck sits overnight, oil leaks past them, pools in the cylinder, then gets burned when the truck is first started. If the vehicle continues to blow blue smoke as you're driving it, then my friend your rings are probably worn out. If it is the rings, you will notice an excessive consumption of oil, whereas with valve guides, not as much. Replacing the valve guides is a fairly straightforward process. Replacing the rings is very involved, so be sure to have a good experienced person with you.

 

what you have described says "valve seals" to me ... but a compression test wouldn't be a bad idea at all.

valve seals : far less complicated/expensive than a ring job.