I recently bought a used car that seemed fit and well. The engine started easily, ran smoothly and performed well. But after a short while, it developed a whole lot of engine problems. Why might have caused that? -- Darius
Engines wear out, but usually very gradually and only one thing at a time. If lots of things are going wrong almost simultaneously then the engine has probably been pre-damaged – most likely by severe overheating at some point. Odd noises and/or a smoky exhaust are usually clues.
While momentary overheating can do little or no harm, severe and prolonged overheating changes the temper of metals and causes warping, can burn valves and crack piston rings and other moving parts, score the cylinder walls, blow gaskets and seals and cause leaks, degrade lubricants, distort bearings, and ultimately even snap rods.
As this damage progresses (from minimal to massive in a matter of minutes), the engine will first have a tendency to stall at low revs and eventually “seize up” completely.
Even if the engine is turned off before those consequences are terminal, and the engine seems to run normally once the cooling system has been fixed (and hopefully the oil has been changed) all the affected elements may have been “rapid-aged” and later start to fail in an almost simultaneous cascade of problems.
Most motorists will experience overheating at some time and that is not an instant disaster.
If an engine overheats, even right up to the red line, but the driver promptly spots the problem and stops to fix it, there is a good chance that no harm will have been done.
The red line is reached when the coolant reaches the boiling point of water and simply means the cooling system isn’t doing its job properly.
But if you keep driving without a fully functional cooling system, the temperature of components inside the engine (which the gauge does not measure) get progressively hotter, reaching temperatures even the hardest steel cannot live with.
And even if you stop before those components deform or fail, they will have been weakened and changed, and something between a cascade of problems or complete catastrophe awaits.
For prevention, make a habit of often glancing at the temperature gauge when driving. Even if the coolant level is “always” okay, don’t stop regular under-bonnet checking.
The gauge should never go above “normal”, even in stressful conditions. If it does, even slightly, there’s a weakness. Have the system checked. If the gauge gets anywhere near the red line, stop!
Find and fix the fault before resuming. If your car starts to stall at low revs, first and foremost immediately check the temperature gauge.
