Puff of white / blue smoke when letting off.

[jamesthebikeguy]

My 7.3l has 161k, and within the last 1k it has started releasing a puff of smoke when I let off the throttle. It's a small cloud and only smokes when you let off quickly.

The smoke only happens after the engine was under load, such as full throttle acceleration, or when towing a heavy load.

There is no smoke when driving normally or on start up.

I am confused because there is no smoke under-load, and it is a white/blue color, not quite like its burning oil and not clear white.

Searched around have not found answers so thanks for the help!

[pablito]

usually blue smoke is from bad exhaust valve seals, it sucks some oil down past the valve stem and is burnt up on the valve. Its not the end of the world, it actually keeps the guides lubricated so they don't wear as bad.