Sometimes it leaks, sometimes not!?!?

XK-Engine
1

My 150 has a 3,8 L engine whose rear crank seal was replaced with a rubber one 4 yrs ago. During the first year it was bone dry, but has since leaked every now and again. When I returned to the garage 2 days ago, after a month, the white floor had a ”large pool” of oil under the rear crank seal. The floor has a slight tilt, so I cant say the diameter, but the trail was about 3ft long.
I drove it yesterday, and after 12 hrs there wasnt even s drop on the floor.
I have noticed this irregular pattern before. Sometimes it leaks, sometimes it doesnt.
Any thoughts on this odd behaviour?

2

It only takes a small amount of oil to leave a large stain, especially if the floor is sloped and sealed with paint.

To minimize leaks, drive the car more often and run it with 1 quart less oil than spec. Unless you are doing consistent high speed runs, you will be fine with the lowered oil level, and your leaks should be minimal.

1 Like
3

Unless on a very long, hard highway run, or on the track, I always ran Tweety at the bottom of the cross hatching. It makes an amazing difference.

4

I agree with with both of you, and leaned about this several years ago, probably from you.
I checked the stick and it read about 1/3 between the 2 cut marks on the dip stick.
It is a 3,8 block with correct sump for the 150.
The stick is plain, with no marking, just two 2mm cits for lower and upper marks. Perhaps not the right stick. I can compare with one of my 140s (for distance between collar and markings).

5

I often make my own low/high marks (edge notches, made with a file) based on a total drain and refill (minus 1 quart for the low mark, at target capacity for the high mark).

6

I recently checked the oil after about half a year and it didn’t even reach the dipstick.

I have a piece of road where I have to stop downhill from high speed and that always tells me when the level is way low,
(I know it’s not harmful because the other car was an oil guzzler and it always had decent oil pressure even though the pressure went to zero many times)

and the pressure didn’t drop yet. I think the dipstick is very conservative, at least on the XJ/420(G). I run mine between half and low usually. Usually it leaks, sometimes not.