Quick Answer
A 2018 Aston Martin DB11 V12 with intermittent misfires was quoted AED 130,000 for engine top-end rebuild. Systematic diagnosis with factory tools revealed degraded ignition coils and a sing
The DB11 V12 is one of the most beautiful engines in automotive history. 5.2 litres, twin-turbocharged, 608 PS — Aston Martin's first in-house twin-turbo V12, replacing the naturally aspirated units sourced from Ford/Cosworth.
When its owner brought it to us, he was shaken. The authorised service centre had diagnosed "possible cylinder head damage and intake system failure" after persistent misfire codes across cylinders 2, 4, and 7. The quote: AED 130,000 for removal of both cylinder heads, inspection, machining if needed, gasket replacement, and intake manifold replacement.
He wanted a second opinion before writing that cheque.
Symptoms:
Owner's history:
The dealer connected their diagnostic tool and found:
Based on these codes, the dealer concluded:
We connected our diagnostic system and confirmed the same codes. But we went further — examining freeze-frame data captured at each fault event.
Critical observation: All three misfire codes had freeze-frame data showing:
This pattern is more consistent with ignition system failure than mechanical (compression) failure. Mechanical issues typically worsen under specific load/RPM conditions.
Before assuming head damage, we performed a compression test across all 12 cylinders.
Results: | Cylinder | Compression (bar) | Specification | |----------|------------------|---------------| | 1 | 12.8 | 12.0-13.5 | | 2 | 12.5 | 12.0-13.5 | | 3 | 12.9 | 12.0-13.5 | | 4 | 12.6 | 12.0-13.5 | | 5 | 13.0 | 12.0-13.5 | | 6 | 12.7 | 12.0-13.5 | | 7 | 12.4 | 12.0-13.5 | | 8 | 12.8 | 12.0-13.5 | | 9 | 12.9 | 12.0-13.5 | | 10 | 13.1 | 12.0-13.5 | | 11 | 12.7 | 12.0-13.5 | | 12 | 12.8 | 12.0-13.5 |
All 12 cylinders within specification. No evidence of head gasket failure, valve damage, or compression loss. The AED 130,000 cylinder head rebuild was unnecessary.
With compression confirmed healthy, we focused on the ignition system. The V12 uses 12 individual ignition coils — one per cylinder.
Method: Ignition coil resistance test and oscilloscope waveform analysis on all 12 coils.
Results:
Root cause (misfires): Three degraded ignition coils. Dubai's engine bay heat accelerates coil insulation breakdown. At 42,000 km in Dubai conditions, coil degradation on a high-output twin-turbo V12 is not unusual.
The P0171 lean code on Bank 1 suggested an air leak in the intake system. With cylinder heads confirmed healthy, we investigated the intake manifold.
Method: Smoke test of the intake system with engine off (pressurised intake with smoke, observed for leaks).
Result: Smoke escaping from intake manifold runner #4 — a hairline crack in the composite plastic runner, invisible to visual inspection but allowing unmeasured air to enter the cylinder.
Dubai connection: Intake manifold runners on the DB11 V12 are composite (plastic/fibre reinforced). Dubai's temperature cycling — 50°C ambient to air-conditioned cool to engine heat — creates thermal fatigue in composite components. Hairline cracks develop at stress concentration points.
Parts replaced:
Total: AED 13,000
Post-repair:
| Approach | Cost | Outcome | |----------|------|---------| | Dealer (head rebuild + manifold) | AED 130,000 | Would have fixed the manifold leak but not the ignition issue | | MotorMec (coils + manifold + plugs) | AED 13,000 | Root cause addressed, full function restored | | Savings | AED 117,000 | 90% reduction |
Critical note: The dealer's approach would have replaced the intake manifold (fixing the lean code) but would NOT have replaced the ignition coils (because they attributed the misfires to cylinder head damage). After spending AED 130,000, the misfire codes would likely have returned — leading to further diagnosis and expense.
The dealer read four fault codes and constructed a narrative: "Multiple misfires + lean code = head/intake damage." This narrative was plausible but untested. No compression test was performed. No ignition system analysis. No smoke test.
The codes were accurate. The interpretation was not. Codes describe symptoms. Diagnosis identifies causes.
Recommending complete cylinder head removal for misfires — without a compression test first — is the automotive equivalent of recommending heart surgery without taking a blood pressure reading. The compression test takes 30-45 minutes and costs AED 400-600. It should be the first step for any misfire investigation, not the last.
Aston Martin parts and labour carry a premium. This is partly justified (hand-built, low volume, specialist tooling). But it also creates a psychological barrier: "It's an Aston Martin, so repairs are expensive" becomes an excuse for not pursuing the most cost-effective diagnostic path.
Q: Does MotorMec have Aston Martin-specific diagnostic tools?
A: Aston Martin vehicles from 2004 onward use diagnostic systems based on Volvo/Ford architecture (VIDA/DIVA), and more recent models use proprietary Aston Martin diagnostic tools. We have coverage for current diagnostic protocols. For very specific Aston Martin-only functions (bespoke interior configuration, certain software updates), the authorised dealer may still be required.
Q: How common is this misdiagnosis pattern?
A: Extremely common across all brands. We see approximately 3-5 vehicles per month that were quoted major mechanical work (AED 10,000+) where the actual repair was electrical or maintenance-related (under AED 5,000). The pattern is always the same: fault codes read without systematic testing.
Q: Should I service my Aston Martin at the dealer or an independent?
A: For warranty coverage: dealer. For out-of-warranty diagnostic work and service: a specialist with proper diagnostic capability offers equivalent quality at 30-50% lower cost. Aston Martin's low volume means dealer technicians may actually see fewer of your model than a specialist who attracts Aston owners seeking second opinions.
Q: How long should ignition coils last on a V12 in Dubai?
A: Plan for 40,000-60,000 km in Dubai conditions, versus 80,000-100,000 km in Europe. On a twin-turbo V12, engine bay temperatures are extreme. Replacing all 12 coils preventively at the 50,000 km service is cheaper than diagnosing intermittent misfires later.
Q: Is the DB11 V12 reliable?
A: Mechanically, very reliable. The 5.2-litre twin-turbo V12 is a modern engine with robust internals. Dubai-specific issues are consumable and electronic — ignition coils, intake components, turbo auxiliaries — not fundamental engine weaknesses. With Dubai-adjusted maintenance, the DB11 V12 is an excellent long-term ownership proposition.
If your Aston Martin — or any luxury vehicle — has been quoted major mechanical work based on fault codes alone, pause. Ask if a compression test was performed. Ask if the ignition system was tested. Ask what was eliminated before the expensive diagnosis was reached.
Equipment. Knowledge. Patience. MotorMec diagnoses before quoting. A AED 600 compression test before a AED 130,000 recommendation should be standard practice. At MotorMec, it is.
No Fix, No Fee. If we can't identify the root cause, you don't pay for diagnostic time.
Reviewed by [Performance Vehicle Specialist], MotorMec Dubai. Last updated: February 2026
