gwf545

I have a 2005 545 and have been reading here about how numerous V8 owners have had oil leak problems, especially from the O-ring on the alternator mounting bracket where it attaches to the engine block. I have under 80K miles on my 545 and haven't had any leak problems so far, but I was wondering what I could do to help prevent them.

I change my oil & filter every 5-7K miles and I think that could help keep the level of volatile gasket hardening contaminants down to a more reasonable level. This week I am also changing out my crankcase vent valves (CCV) in case when the originals eventually go bad they have something to do with internal gas pressure build up and contamination that can cause oil to start leaking.

I was also wondering if it might help to occasionally add an engine oil stop leak in order to help the gaskets stay soft. I've used them before to successfully stop leaks in U.S. made cars, but never in a Bimmer or as a preventative. Lucas 10278-1 Engine Oil Stop Leak is supposed to be good.

Has anyone thought about this or tried it? Could it do more harm than good?

Any other ideas on how to avoid leaks would be appreciated.

gwf545

I was reading more about leak prevention on - Bob is the Oil Guy and I think using this 5W-30 Synthetic Oil | Mobil 1™ High Mileage 5W-30 may be a better solution than adding stop leak. It has seal conditioner that may help keep the gaskets soft.

tonyb635

There is nothing you can do except sit back and wait. I would never consider adding stop leak or anything like that to my engine. I am sure it would create more of a head ache later.

gwf545

Why are you sure? What about high mileage oil?

tonyb635

5w 30 full synthetic is what I have always used. What is recommended for your engine? I would have thought the same or at least something similar. I do think using something like this is your best option. But it's only my thoughts.

wcr3d

Because you are adding something that is intentionally and designed to create deposits. Which will only continue to build up. And as he stated above your owners manual should be telling you to use high mileage synthetic oil of about the same weight you suggest. I would say 15k miles is high mileage!

KyleB

The best way to avoid oil leaks is to buy a Japanese car.

gwf545

The stop leak products I looked at do no contain solids, they contain conditioners that soften old hard rubber gaskets. The best ones don't make the gaskets and seals swell or damage them, they soften them and prevent them from cracking. The high mileage oils, like the full synthetic 5w-30 High Mileage Mobil 1 that I mentioned, do the same thing but I suspect that they have less of the conditioner and might be safer. I have not read anything about them causing problems.

Btw, High Mileage refers to miles on the car, not miles between oil changes. I agree 15K between changes is nuts which is why I go only around 5k between changes.

gwf545

Thanks, that was real helpful and a great contribution to the discussion.

mag5qc

2004 545i - No significant leaks yet although I've been replacing factory hose clamps with fuel injection clamps as a preventative measure. A big consideration nobody seems to talk about is re-torquing components (valve covers, alternator, etc) that could leak oil. Any thoughts?