The S62 can last 300,000 miles. The S62 can also fail at 40,000 miles. There seem to be many more instances of higher miles than lower, however. These are the primary weak points of the S62:
- Rod Bearings The bearings that surround where the 8 piston’s connecting rods attach to the crankshaft are wearable parts. No surprise, all rod bearings wear, especially with high-revving, high-output V8s. They can wear faster if you use the wrong oil, lug the engine at low RPMs, or drive the hell out of the car on a daily basis, over a long period of time. The S62 was hand built, so each engine can be different. My 2000 M5’s original engine had exactly 192,000 miles on it, with original rod bearings, and no sign of failure when I removed it. The problem with the bearings is, by the time you start to hear the knocking of failing bearings, it can often be too late to simply replace the bearings ($2,500 job or so) and then move on. The force of the pistons slamming into the crankshaft with the play can easily destroy (score) the crankshaft, at which point, the engine needs to come out and be opened up to remove and replace the crankshaft if it indeed cannot be repaired by machining. Now we might have a $5,000 – $7,000 job, or more. If the piston breaks off the crankshaft, it can go up and destroy the valves/head of the engine, at which point the engine is pretty much scrap metal, or an interesting conversation piece for your living room. While rod bearing failure is not terribly common… it happens.
- Timing Chains The timing chains themselves are largely bulletproof- but there are two weak points in the design of the engine’s timing. 1, the chain tensioners. There are a few hydraulic chain tensioners that resemble a hot dog inside the engine. They keep the chain tensioned, so it doesn’t slack and rattle around inside the motor. Over time (100,000 miles or so) these tensioners loose their ability to hold the timing chain tight. It’ll run about $100 and an hour’s labor to replace the main tensioner (front, lower left of engine). When/if the tensioner fails, now the chain is slapping around- which speeds up the inevitable failure of the 2nd issue with the timing system: chain guides. The chain is guided around the front of the engine by a series of plastic timing chain guides. Why plastic, BMW, WHY!? Should the guides fail, now the chain is at risk of coming off, which can lead to the engine’s timing to advance or retard to the point of the valves colliding with the pistons, ruining the engine. Replacing the timing chains, guides, and tensioners all at once can be a $5,000 job, as the whole front of the engine has to be taken apart. At 192,000 miles, all of my timing system was original, with the exception of the primary tensioner, which I did 2 years ago at about 175,000 miles. My setup had no chain slap at all. The gentleman that bought my old S62 rebuilt it before putting it in his project E30. He asked me when I did the timing guides last, noting that they looked pretty new! I informed him that they were original; he was shocked. You can generally tell fairly easily if your S62 (or in a car you’re considering buying) is slapping around inside the car. With the engine at idle, slowly unscrew the oil fill cap. Don’t remove it completely, but put an ear down near there and listen. If any sort of a slapping noise gets way louder when you partially lift off the oil fill cap, then you probably have chain slap. Be careful while you’re down there, hot oil can spray around a bit.
- VANOS The VANOS (variable valve timing for intake/exhaust valves) is also way over-hyped. The S62 doesn’t sound good at idle, period. It rattles like a diesel. This gets worse as the VANOS ages, and the splines that drive the system develop some play. Until this is really bad, there is no lack of performance or negative impacts, aside from the rattling sound. It also can make some unpleasant rattling on startup as well, but this is very common, and not really anything to worry about. The startup rattle is caused by a lack of oil pressure in the system, so when the engine fires, the gears are running dry and clattering around until a stream of warm oil is pumped up to silent and lubricate them. If the VANOS seals begin to fail, then timing can suffer, and it can trigger check engine lights and lower power output. Rebuilding the VANOS can be done for around $1,000 in parts (through Dr. VANOS), but the front of the engine has to come apart a good bit- although it can stay in the car. My VANOS, at 192,000 miles, was largely original. There was no check engine light, no loss of power, but plenty of rattle. In 2006, under warranty, the dealer replaced the rubber seals in the VANOS units, that was the only service.
- Carbon Buildup Ignore this, it’s so over-hyped in the community. There are passages within cylinder heads that inject air from the secondary air pump into the combustion engine’s chambers on startup to lean out (over supply oxygen) to make the exhaust hotter, which then warms the catalytic converters faster. These passages in the heads are too narrow in their design, so they get plugged up with carbon deposits (all S62s burn a bit of oil, it’s the nature of a racing-derived V8). When the passages get plugged up, it throws a code: AA, Secondary Air System, Flow too Low. I have a Shark tune on my ECU to disable the AA code, so I have no warning light for it. There is no loss of performance or any down-side, except the annoyance of having the light on if you don’t have a tune. The 2001-2003 engines are a little better, as they drilled the passages wider, but they can still get clogged up.
- Normal stuff. The S62 is a complex engine. It has a lot of electronic sensors that simply need to be replaced every so often. Sensors like the Camshaft Position Sensors (CPS), oxygen sensors, throttle position sensors, spark plugs, thermostat, Mass Air Flow sensors (MAFs) need to be replaced eventually. I have done all of the aforementioned sensors in my car at some point during my ownership. If you have some basic automotive experience, and a decent set of sockets, you can these yourself. Gaskets also fail over time, commonly the valve cover gaskets, oil pan gasket, oil filter housing gasket, and the rear main seal on the S62. Head gaskets seem to be pretty solid, though. Mine were done at 108,000 miles in 2008 just because the engine was apart. They were not leaking then, nor at 192,000 miles.
So, is the S62 a reliable engine? Absolutely, yes. But, not unlike any other engine nearing the 200,000 mile mark, they have some key areas of concern. Which is why I purchased a 2002 E39 M5’s S62 with 122,000 miles on it for my car. I have had new rod bearings, timing chains, guides, tensioners, rebuilt VANOS, and around eight-thousand other parts installed in this newer engine. It was almost completely rebuilt, minus the piston rings (S62 has an alusil block and cannot be honed for new rings). The compression on each cylinder was all in-spec as well. A new S62 from BMW, installed, is around $30,000. _
Find an S62 that has been taken care of and looked after over the years, continue to do the same, and it should take you 200,000 or more largely trouble free miles._
The following two tabs change content below.