My vehicle is a Hyundai Santa Fe 2.0 CDX CRTD and has covered 90,000 miles. My problem occurs when starting from cold, after allowing time for all dashboard lights to extinguish and the glow plugs to heat up. Upon starting, I have noticed that the first exhaust gases are light blue in colour, lasting only briefly. Is this excess fuel being delivered only on initial start-up, or is it something to be concerned about? The engine is not using or burning any oil. David Oates Blue smoke from the exhaust is normally a sign of lubricating oil being burned after entering the cylinder. When this is evident on first starting up, it can indicate that the oil control rings are clogged and that the initial stroke of the piston is allowing a minimal amount of oil to pass, or else that a small amount of oil has slipped past the valve stem seals and into the combustion chamber. Another possibility is that the oil level is being increased by unburned fuel getting into the sump, raising and degrading the lubricating oil. Keeping a close eye on the oil level will ensure this is not the case.
If the smoke is more of a greyish colour, it indicates the presence of unburned fuel in the exhaust. This may be due to slight over-fuelling at startup or faulty injectors that are weeping when rested. It may also be the result of low combustion pressure, due to wear in the piston rings or valve seats.
Coolant leaking into the cylinder will cause a white smoke.
Given that your engine starts without problem and does not appear to burn oil – and working on the assumption that you have confirmed the coolant level – I would suspect the small amount of smoke on start-up is not a major concern and may be indicating a possible carbon build-up on the piston oil control rings.
You do not mention when the vehicle was last serviced. Nor have you indicated your daily mileage, but if this is generally a short distance, the vehicle may benefit from a 30-40 mile run and an oil change.