Engine overhaul: what it costs and what the options mean
Field overhaul, factory overhaul, factory reman, or a new engine. Four very different prices, four different warranties, and one thing they do not tell you — what any of it does to the value of the airplane.
The largest single maintenance event in a piston airplane’s life, and the one every buyer is implicitly pricing when they look at hours since overhaul. Understanding the options is worth real money both when you spend it and when you eventually sell.
The four routes
| Option | Typical | What you get |
|---|---|---|
| Top overhaul | $8,000 – $20,000 | Cylinders only. Not a real overhaul; buys time. |
| Field overhaul | $28,000 – $50,000 | A shop rebuilds your engine. Quality varies with the shop. |
| Factory overhaul | $40,000 – $65,000 | Manufacturer rebuilds to overhaul limits, with a warranty. |
| Factory reman | $45,000 – $75,000 | Zero-time logbook, new-part limits, best warranty. |
| Factory new | $55,000 – $110,000+ | A new engine. Rarely the economic choice. |
Those ranges are wide because engines are wide — a four-cylinder normally aspirated engine and a turbocharged six are very different animals. Get a quote for your specific engine before budgeting from any table, including this one.
The distinction that matters most
A factory remanufactured engine is zero-timed. The logbook starts again at zero hours, because the manufacturer rebuilds to new-part tolerances and issues it as a reman. A field overhaul does not do that — the engine keeps its total time and the logbook records hours since major overhaul against a total that keeps climbing.
That difference is worth real money on resale, and it is worth thinking about before you spend rather than after. An airframe with 4,200 total hours and an engine at zero since reman reads differently to a buyer than the same airframe with an engine at zero since field overhaul on 4,200 total. Both may be mechanically excellent. They do not price the same.
What "top overhaul" actually means
Cylinders, valves and pistons — everything above the case. It leaves the crankshaft, bearings, camshaft and case untouched, which is where the expensive failures live.
A top overhaul on an engine at a thousand hours with a specific cylinder problem is sensible maintenance. A top overhaul on an engine at eighteen hundred hours is usually money spent to defer a decision, and buyers read it that way — "top overhauled at 1,800 SMOH" in an advert is a sentence that invites questions.
When to overhaul
Under Part 91, for a privately operated aircraft, the manufacturer’s recommended TBO is guidance rather than a hard limit, and engines are run on condition. What "on condition" means in practice is a monitoring programme rather than an opinion:
- Oil analysis at every change, watched as a trend rather than a single result
- Filter cut open and inspected at every change — metal is the conversation-ender
- Compression checks in context, with the mechanic’s notes on what they heard, not just the numbers
- Borescope inspection of cylinders, which finds things compression testing does not
- Engine monitor data, if fitted — the single most useful tool an owner can have
- Oil consumption trend, which changes before anything else does
An engine with clean oil analysis, no metal, stable consumption and good borescope results may run comfortably past TBO. One making metal at fourteen hundred hours needs attention regardless of what the manual says. The number in the manual is the least informative data point you have.
What it does to the airplane’s value
Less than it cost. This is consistent and it surprises owners every time.
A fresh overhaul adds real value, but not the full price of the work, because the buyer did not choose the shop, did not supervise the work and inherits whatever break-in the airplane got. Meanwhile a run-out engine deducts <em>more</em> than the overhaul cost, because the buyer is pricing in their own risk and downtime as well.
The practical conclusion: if you intend to keep the airplane, overhaul when the engine tells you to and enjoy the years afterwards. If you intend to sell within a year, selling with a run-out engine and pricing it honestly is very often better arithmetic than overhauling first — and it is certainly less work.