M60 Chain Rattle on Start & Oil Leak

[TiagE39]

M60B30. After sitting more than a few days without running, there is a chain-rattle type noise on startup that dissipates after about 3-5 seconds. Valvetrain sounds slightly tappety thereafter until fully warmed or driven for a short distance. To be fair my E34 is in temporary storage at the moment, and can sit for days until it is started to be moved (I share a garage with some fellow BMW enthusiasts). After doing some research, it sounds like I might have a failed drainback valve in the oil filter housing, or a slow/old chain tensioner.

Adding to this is a driver's side oil leak which appears to be getting slowly worse over time. I'm coupling these symptoms together as I wanted to see if there could be a common cause. I know the oil filter housing's hoses and piping are all on the driver's side of the M60 (and carry the pressurized oil from the pump).

Will also note that the driver's side valve cover gasket is very overdue (parts are on order) so I realise that could be the culprit.

While I work to solve this, should I take any precautions about moving or running the car?

[savv213]

lmao

[moroza]

A leak enough to lose meaningful pressure would likely be described in stronger terms than "slowly getting worse over time." Expected words might include "gushing", "pissing", "puking", "dumping", "spewing", "hurling", and many, many more.

Even on a perfectly healthy engine, avoid short cold starts, exactly like the kind just to move a car around a shop every few weeks. It's brutal on engine internals, in part because they can flood, washing gasoline into the oil, with all the consequences that comes with. I lived in a community where an occasional complaint was that I valued the machinery over human sweat; nobody understood why I so preferred to round up helpers to push rigs around a lot rather than start them. Those that had the patience to listen to the reason, about half, then stopped complaining. If you have to start it, drive it around for three times as long as it takes for coolant to come up to temp, or longer. On this car, though, I'd first change the oil.

[TiagE39]

A leak enough to lose meaningful pressure would likely be described in stronger terms than "slowly getting worse over time." Expected words might include "gushing", "pissing", "puking", "dumping", "spewing", "hurling", and many, many more.

I think I needed someone to confirm my paranoia, haha. Right now I'm running Mobil 1 High Mileage 10W-40 (I normally run LM in my cars but the last oil change was a little unplanned). I was planning on LM Leichtlauf 10W-40 on the next oil change, but should I bump up the weight? Maybe 15W-50 or 20W-50?

[moroza]

No, use the correct weight after fixing leaks. Change the oil, give it a good long drive including an Italian Tuneup, and there's a good chance the problem will go away. If not, there'll be further diagnostic steps to take, but start with this.

[Wcsco123]

Give the engine a good clean to try pinpoint the location of the leak, if its the drivers side Its likely a bad valve cover gasket or high pressure oil lines connecting to the filter housing.
One thing to check for a noisy start up is the oil pump, the bolts are prone to loosening over time... I found two bolts rolling around my oil pan a few years ago. You'll also be able to see if there is any issues with the guides. Replace the oil pan gasket while your at it for piece of mind!

Also! try out 5w-40 Molygen. My 540 runs smooth as butter with that stuff and it has UV dye incorporated into the additives for finding leaks.

[TiagE39]

Coming back to close the loop on this...the cause of my leak AND noise was a loose/bent oil cap. One of the metal tabs that "locks" the cap to the valve cover was bent so the cap wouldn't really seal and would sit at an angle. So technically I was hearing my timing chains, but because the oil cap wasn't on right. After the cap was re-bent (a new one is on order) the noise isn't present on cold starts now.