Hi, I have a ford Essex V6 3 litre in my Stag. It runs fine, however once hot, smoke escapes from the filler cap (which is a simple push on). If I remove the dipstick smoke comes from there as well. It has not had a lot of regular use in the past 13 years and I wonder if it needs a good dosing with something. Has anybody had the same problem or got any ideas?

Hmmmp....same problem as mine...need also help on this.

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clearly you have worn cylinder bores/pistons/rings or the piston rings are stuck.
if the smoke is a trickle with no real pressure the engine could be usable and there could be a problem with the crankcase breather valve or hose.
if the smoke has that certain enthusiasm the engine will almost certainly be suffering from low compression, poor starting and performance and be ready for an overhaul.
if the smoke puffs regularly the problem is likely confined to just one cylinder and likely be more dramatic.
a cylinder leakage test or a wet and dry compression test would help pinpoint the cause.
Redex treatment might help free stuck rings but a stripdown is almost unavoidable. do not forget to glazebust the bores and run in the new or refitted rings in with special running in oil or a straight SAE 30.