Oil's not well with engine

I HAVE a 2002 Peugeot 206 1.4 in which the oil warning light is always on and the message Stop! keeps showing on the dashboard. Then the car just stops. When I restart, the same signs remain on constantly. I will drive for about 3km, but then it will stop again. The oil dipstick shows there's enough in the engine. What's going on? - Oupa

I'm afraid this doesn't sound good, Oupa. The oil warning light is an indication that the oil pressure is too low.

Many people are under the impression that it tells them the oil level in the sump is too low, but that isn't the case.

The oil pressure can be dangerously low even when the sump is filled to the correct level. Of course, if the level in the sump should drop to below the oil pick-up point, the oil pump will be sucking air instead of oil, which is one of the possible causes of low oil pressure.

But even then, the low oil pressure switches on the warning light, not the low oil level.

On your 206 we can assume the oil level has been correct all along, so we must look elsewhere for the cause of low oil pressure. It could be a blocked oil filter, or a failed oil pump, to mention two possibilities.

When the oil pressure drops below a certain point, the engine faces a serious threat. Without sufficient pressure to maintain an oil film between the rotating crankshaft and the main and big-end bearings, metal-to-metal contact occurs, leading to rapidly escalating temperatures, and if the engine isn't switched off quickly enough, engine seizure will follow when the rubbing surfaces get so hot that they are welded together.

The same thing will happen if not enough oil is sprayed onto the cylinder walls to form a lubricating film between the piston rings and the cylinder walls.

This ghastly scenario is the reason manufacturers are so worried about a drop in oil pressure. On the 206, Peugeot have gone even further: just in case you miss the glaring red warning light, they have made sure that the startling message: Stop! is displayed.

I realise all men are sceptical about idiot lights on the dashboard but, with the advantage of hindsight, it would have been better to take the warning seriously the first time appeared and to have taken the car to a Peugeot workshop so they could remove the oil pressure switch, screw in a pressure gauge and check whether there really was a problem with the pressure.

As it now stands, one possible explanation for the symptom of the car restarting after a while, then stopping again a short distance later, is that the engine overheats, with consequences we can only speculate about, then cools down sufficiently to restart, but soon overheats again. I hope it's not as bad as that, but I think you should get the car to a trustworthy and well-equipped workshop as soon as possible.

If low oil pressure is confirmed, the difficult question remains: Why is the oil pressure so low? A blocked oil pick-up screen in the sump or excessive bearing wear are two possibilities that come to mind, in addition to the ones mentioned earlier.

There's no doubt that a proper oil pressure gauge is far superior to an idiot light.

By all means retain the idiot light, preferably supplemented by an intolerable buzzer to warn you if something catastrophic is about to occur as you are barrelling through the Karoo on a dark winter's night.

However, we would like to have an oil pressure gauge as well, to provide a continuous indication of the general health of the engine.

It is one of the few worthwhile accessories, in my view, yet it's seldom fitted on entry-level and mid-range cars, presumably for reasons of cost and to avoid "information overload" from a plethora of gauges.

Given the choice of an oil pressure gauge or electric windows, I wouldn't think twice!