MAJOR 4.8is Oil Leak

TheHerd · Post by **TheHerd** » Fri Jun 05, 2026 7:49 pm

Hi guys,

I have a 2005 4.8is with 136k miles on the clock with only what I can describe as being a "medium-to-major" oil leak!

I took a 30 mile drive yesterday and when returning I parked it up in the garage with a folded out cardboard box and drop sheet underneath. I have attached a photo showing the amount of oil that dropped to the floor. The engine was directly above the cardboard box and the drop sheet runs to the middle of the car. Having done some Google/ChatGPT research this could most likely be the alternator seal leaking under pressure while driving and then the wind blowing the oil all the way down the bottom of the car towards the gearbox, and then dripping like this when stationary.

What would your thoughts be? Could it be something else, other areas to check?

How hard is it do replace the alternator seal as a DIY mechanic on axle stands?

X5Sport · Post by **X5Sport** » Fri Jun 05, 2026 7:56 pm

Worth also having a look at the front crankshaft seal. Have a look from above and see if you can see what’s wet.

Can’t help with how possible repairs are with just axle stands as I’ve never tried it.

TheHerd · Post by **TheHerd** » Fri Jun 05, 2026 9:56 pm

X5Sport wrote: Fri Jun 05, 2026 7:56 pm Worth also having a look at the front crankshaft seal. Have a look from above and see if you can see what’s wet.

Can’t help with how possible repairs are with just axle stands as I’ve never tried it.

Excellent, thanks for the additional input.
Going to get it jacked up at the weekend to take a closer look and take some more photos.

Leslie · Post by **Leslie** » Sat Jun 06, 2026 10:56 am

Front Crank seal most likely as said , alternators don't have any oil in them to leak out , changing it yourself on the drive will be a right pain and very challenging going by others experience on here

XSeries-forum

XSeries-forum