Just for starters, I really need to know what year the car is and what engine it has before even knowing where to start looking for the problem. But in most cases like yours, the solution will be to do with either the fuel or spark in the engine and/or the computer that controls these functions.

You could have something like a poor earth connection, which sounds simple but can be a real trial to locate. But equally, there could be a glitch in the fuel system such as a lazy pump with an intermittent fault, or something in the ignition that is momentarily dropping the ball. A faulty sensor can also throw up problems just like this one.

The best advice is to have the car scanned for fault codes as this will put you a long way towards homing in on the actual cause.

Depending on the amount of fumes visible (it’s not actually steam) this could be a small or large problem. Here’s how that works: A small amount of white fumes from the oil filler cap is not so bad, but what you don’t want to see are gales of the stuff blowing out when you remove the cap.

These fumes are caused by pressure from the combustion process in the cylinders finding their way into the crankcase. As an engine wears, more and more pressure can find its way into the crankcase, increasing the fumes. When the fumes increase, this is a clue that your piston rings (among other things) are becoming worn over time and kilometres.

But you could also be looking at a car with a faulty PCV valve. This valve has the job of removing the fumes and sending them back through the engine to be burnt a second time. But if the valve is faulty, the engine won’t be vented sufficiently and the fumes suddenly become visible again. So, have the car checked out at a workshop who will be able to perform a compression test to tell whether the engine is in good internal condition or not, as well as check the PCV valve for correct operation, If the problem is the latter, it’s an easy, cheap fix.

The Elantra’s 1.8-litre engine has reputation for piston slap and ticking noise, hence the offer to cost of the parts. Carmakers will often make an offer like this, they pay for the parts, and you pay for the labour. They usually argue that you have to bear some of the cost because you’ve had the use of the car for a period of time. If you want to pursue it try to convince Hyundai to come around to your way of thinking by direct negotiation, or enlist a government body like the ACCC to help you.