S85 Oil in the BMW E60 M5: How Not to Overfill and Keep the V10 Alive

The short version. The S85 in the BMW E60 M5 and E63 M6 is a high-revving V10 with a quasi-dry sump, and it is unusually sensitive to oil level. The most common owner mistake is pouring in 9.3 liters per the official specification instead of the recommended 8.8 liters at a change with a new filter. Overfilling causes elevated pressure, leaks, and coked-up intake valves. Here’s the right way to change the oil, measure the level accurately, and get through break-in.

The Problem

You bought an E60 M5, poured in 9.3 liters of oil “per spec” — and a few thousand miles later you spot oil weeping around the pan. Sound familiar? The official capacity figure assumes a completely dry engine; in the real world, oil stays in the system after a drain. Overfilling is the most common S85 owner mistake, and it can seriously shorten the engine’s service life.

Overfill Symptoms

• Oil weeping at the pan and seals
• Elevated crankcase pressure
• Carbon buildup on the intake valves
• Loss of power
• The level indicator reads MAX or higher after a change

Why It Happens

The S85’s lubrication system was engineered for high loads and lateral acceleration. The key feature is the quasi-dry sump, which prevents oil starvation. The primary oil pump is actually two pumps in a duocentric layout: one feeds oil to the crankshaft and camshaft bearings, while the second pumps oil from the front of the pan to the rear. Under acceleration and braking the oil shifts, and without that second pump the front of the pan would run dry.

But the design creates a problem: oil can linger in the front of the pan even after a full warm-up, and that skews the level reading. The level measurement system has a sensitivity threshold: top-ups under 0.5 liter don’t register on the indicator. Add 200–300 ml and the display shows the same level — which invites another top-up and a stealthy overfill of 0.5–0.7 liter.

The Fix: Step-by-Step Oil Change

Step 1. Warm the engine. Bring the oil temperature above 160°F (70.0 °C). Hot oil is thinner and drains better. Cold oil leaves up to 0.3–0.5 liter of old oil behind in the engine.

Step 2. Check the level before draining. Use the BC function of the on-board computer. If the level reads maximum, the previous change was done with an overfill.

Step 3. Drain the oil. Undo the drain plug at the rear of the pan and let the oil drain for at least 15–20 minutes. Some oil remains in the front of the pan and in the oil cooler. For a more complete drain, remove the oil filter housing.

Step 4. Replace the filter. Use an original filter or a quality equivalent. Coat the sealing ring with fresh oil.

Step 5. Fill with oil. Pour in 8.8 liters of Castrol TWS Motorsport SAE 10W-60 synthetic. It was developed specifically for BMW M’s high-revving engines. Don’t experiment with other viscosities — the S85 demands its specification.

Step 6. Check the level. Run the engine for 1–2 minutes, shut it off, and wait 5–10 minutes. Check the level through the on-board computer. Between MIN and MAX is normal; at MAX or above, you’ve overfilled.

Step 7. Correct an overfill. Drain about 0.4 liter through the oil filter housing — easier and cleaner than crawling under the car to reach the drain plug.

⚠️ A contradiction in the specifications. The official capacity is 9.3 liters; the recommended volume at a change with a filter is 8.8 liters. The gap exists because the 9.3-liter figure assumes a completely dry engine. In reality, oil remains in the oil cooler, the passages, and the pump after a drain — which is why 9.3 liters produces an overfill.

How to Measure the Level Accurately

For a precise reading, use the extended measurement mode — it’s available in the on-board computer menu and averages the readings over several engine-run cycles.

• Don’t trust the indicator on small top-ups. Anything under 0.5 liter doesn’t register. Add oil in 0.5-liter portions and recheck the level after a short drive.
• Check the level on a warmed-up engine. Cold oil takes up more volume than hot oil.

Engine Break-In and the CBS Reset

During the break-in period (about 1,200 miles), reset CBS (Condition Based Service) only through GT1/DISplus — BMW’s professional diagnostic equipment.

A CBS reset through the instrument cluster does not change the oil-level calculation algorithm. The system keeps working off the old data, which produces incorrect readings.

Break-in oil requires a special DME algorithm, activated through GT1/DISplus. Break-in oil carries a higher additive content to help the parts seat, and the algorithm changes engine operating parameters. Without activation you risk an incomplete break-in, which shortens the engine’s service life. Once break-in is complete, the oil and filter are swapped for standard ones and the algorithm is switched off.

Prevention: Oil Change Checklist

• [ ] Warm the engine to 160°F (70.0 °C) before draining
• [ ] Let the oil drain for at least 15–20 minutes
• [ ] Fill with 8.8 liters of Castrol TWS Motorsport SAE 10W-60
• [ ] Check the level in extended measurement mode
• [ ] Top up in 0.5-liter portions
• [ ] During break-in, reset CBS only through GT1/DISplus

The Bottom Line

The one rule for the S85: don’t overfill. Better to be 100 ml short than 200 ml over — excess oil isn’t a reserve, it’s a problem. Use 8.8 liters of Castrol TWS Motorsport SAE 10W-60, warm the engine before draining, check the level in extended measurement mode, and don’t trust the indicator on small top-ups. During break-in, reset CBS only through GT1/DISplus. Follow these rules and the V10 keeps its service life — and you avoid a costly repair.