Reference specification for the 3.0-litre TDV6 and SDV6 diesel, fitted to Discovery 3/4/5, Range Rover Sport (L320/L494), and L405. Oil capacity, correct grade, change interval, and the 60% threshold applied.
The 306DT (3.0 TDV6/SDV6) takes 7.4 litres of oil with a full filter change [PLACEHOLDER — confirm vs OEM workshop data], using a low-SAPS 5W-30 viscosity oil meeting JLR specification STJLR.03.5005.
Full specification table, variant differences, common mistakes, and the 60% threshold applied below.
| Spec | Value |
|---|---|
| Capacity with filter change | ~7.4 litres [PLACEHOLDER] |
| Capacity without filter change | ~7.0 litres [PLACEHOLDER] |
| Viscosity grade | 5W-30 (low SAPS) |
| JLR specification | STJLR.03.5005 [PLACEHOLDER — confirm exact spec number] |
| Change interval | 16,000 miles / 12 months [PLACEHOLDER] |
| Oil filter type | Cartridge, top‑mounted |
Figures marked [PLACEHOLDER] require confirmation against the OEM workshop manual before this page goes live — flagged here deliberately rather than guessed.
The 306DT is fitted across several generations, and while the core specification is consistent, sump capacity and filter position vary slightly by application.
| Application | Capacity Note | Filter Access |
|---|---|---|
| Discovery 3 (L319) | Standard 7.4L figure applies | Top‑mounted, accessible from above |
| Discovery 4 (L319) | Standard figure | Top‑mounted |
| Discovery 5 (L462) | Standard figure, some early builds noted slightly higher sump capacity | Top‑mounted |
| Range Rover Sport (L320) | Standard figure | Top‑mounted, tighter access on earlier models |
| Range Rover Sport (L494) | Standard figure | Top‑mounted |
| Range Rover (L405) | Standard figure | Top‑mounted |
The manufacturer's 16,000‑mile service interval assumes motorway‑weighted use at normal operating temperatures. In real‑world UK conditions — particularly short urban journeys, towing, or low‑speed off‑road work — the oil degrades faster through soot accumulation and fuel dilution, even on a healthy engine. Independent specialists we've spoken to frequently recommend a 6,000‑mile oil change interval for 306DT‑powered vehicles used in these conditions, irrespective of what the service computer indicates. This is a practical adjustment, not a criticism of the engine design — the same recommendation is common across modern high‑output diesel engines with DPF systems.
The key point is simply that oil condition is the single most important variable affecting the 306DT's well‑documented crankshaft bearing failure pattern — which is not caused by oil choice, but by a mechanical design weakness in the bearing coating itself. Correct oil, changed regularly, gives the engine its best possible odds of exceeding 100,000 miles without major intervention. The crankshaft bearing failure page covers that mechanism in full detail.
On the Land Rover site, we apply a 60% repair‑to‑value threshold: if the total cost of a reconditioned engine supply and fit exceeds 60% of the vehicle's current market value, scrapping or breaking the vehicle is the financially rational choice.
For the 306DT, a reconditioned supply‑only engine costs £6,500–£9,500 [EM-QUOTE], with R&R labour at approximately 15–20 hours at independent rates. The total fitted cost typically lands in the £8,500–£11,500 range, depending on location and ancillaries. For a Discovery 4 or early L405 valued at £10,000–£14,000, a full replacement sits right at or just above the 60% threshold, meaning a significant proportion of owners in that value band will conclude that replacement doesn't make financial sense.
This is why the 306DT features so prominently in our Economics & Scrap Decision guide — the combination of a very high replacement cost and the vehicle's relatively low residual value on older examples means the "scrap it" answer is more common than owners expect.
The oil specification and service interval don't change this threshold — but they do affect whether you get to make that decision at 120,000 miles or 180,000 miles.
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Last Verified February 2026Reviewed on a regular schedule, not left to go stale.
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