Read and protect the engine's oil pressure
Oil pressure is the clearest indicator of health on the Aceca's six-cylinder engines. Learn your engine's normal hot and cold readings from the manual, watch for a low hot-idle figure, and act on any downward trend early, most bottom-end damage follows months of quietly falling pressure that was there to be seen.
Tools
- Mechanical test oil-pressure gauge
- Basic spanner set
- Torch
Parts / supplies
- Correct-grade engine oil (per manual)
- New oil filter
- Sump and filter seals as needed
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Procedure
Establish the normal figures for your specific engine, the AC 2.0, the Bristol, or the 2.6, from the workshop manual, for cold, hot-running and hot-idle. There is no single correct figure across the variants.
Warm the engine fully, then note the hot readings at idle and at a steady cruising rpm, and compare them with the manual.
If the dashboard gauge reads oddly, confirm it with a mechanical test gauge at the take-off point before condemning the engine, a faulty gauge or sender is a common false alarm.
Investigate the cheap causes of low pressure first: oil level and grade, the relief valve, and the pump pick-up gauze or filter, before assuming worn bearings or pump.
Change the oil and filter to the manual's grade and interval; old or over-thin oil is a frequent cause of a low reading in these engines.
Note that the AC 2.0 engine drives its camshaft, distributor and dynamo from the rear of the crankshaft, an unusual layout; check the manual before assuming a conventional arrangement.
Warnings
- A sudden loss of oil pressure means stop the engine immediately, running on low pressure destroys bearings within minutes.
- Use the oil grade specified for the engine. A modern thin multigrade can read low in a worn engine designed for a thicker oil.
Related faults
About the author
A lifelong classic-car enthusiast in North Yorkshire, near Thornton-le-Dale, who owns and maintains an AC Aceca, writing the single-model reference he always wished existed. Read the full bio.