Oil Changes Show Progressing Oil Leaks. Synthetic To Blame

ED. · March 8, 2012

I've owned my 98 over a year now and this is my third oil change and I've noticed some leaks which I was told by my dealer was the valve covers (I've also confirmed myself with being under there).

There was a theory from my BMW days where people who started using fully synthetic oil (after years of base oil) had leaks like mine. This seems to make sense but I don't know what type of oil the P/O used.

Has anyone else ever experienced this? Another reason I like to DIY oil changes so I can are what's going on. Car has 143,000 so I'm not surprised it has some leaks and feels like it needs motor & transmissions mounts. Can't wait for warm weather!

curiousB · March 8, 2012

Sounds like an urban myth....

landar · March 8, 2012

I have changed over from dino to synthetic in my LS400 and LS430 with no leaks. Synthetic is thinner than a comparable dino weight at cold temperatures. It is most probable that some aging gaskets in your engine just need replacing and/or bolts tightened. Here is some interesting reading at "bob the oil guys" university. Enjoy -> http://www.bobistheoilguy.com/motor-oil-103/

ED. · March 8, 2012

Pretty good read! I will start changing some gaskets and keep an eye on it. Pretty messy under there so I will definitely get on it.

billydpowell · March 8, 2012

I have never used any sync, but I dont think it matters to your engine what kind you use in todays engines... in the old (59 and back) engines it did make a difference between petroleum and pennsylvania paraffin base oils as far as burning oil, and leaks. but those days are gone (thanks)... so fear not, just keep it clean so it can help keep heat away from friction parts..

da_fugative_7 · March 11, 2012

When I switched over to synthetic, I just changed over my gaskets. They were in fairly good condition, but I wanted everything nice, tight, new and clean. I don't know if they would've started leaking after the oil switch, but I seriously doubt that changing from dino to synthetic will cause your engine to leak oil. I also think it has something to do with how the P.O. maintained the car...IMO....