Small Milkshake found while fixing Vacuum Leak - ideas to fix?

1989 Mercruiser 454 magnum (rectangular port heads)
all stock, quadrajet carb, aluminum high-rise intake
Pushes a 1989 baja sunsport 210 (21') with a 25p turbo prop


Engine was idling poorly and getting inconsistent WOT rpms (ranging from 4400-4800 depending on the day, should rev to 4800-5000 all the time)

Based on poor idle and inconsistent WOT, put on the vacuum gauge and found partially low vacuum (13-14). While testing for leaks with WD-40 found a leak at 1) intake gasket, and 2) q-jet primary throttle shaft. So I decided to fix the throttle shaft and replace the intake gaskets at once...

Unfortunately, I found a small milkshake when looking in a valve cover vent hole and pulling out the distributor (see pics at the bottom). Whats weird is that the dipstick shows a normal oil level with absolutely no milkshake at all. Also the lifter valley/camshaft area only has a little bit of milkshake.

What are thoughts about what I should do now? And what is potentially causing the small shake? I have seen some "blow by" out of valve cover vents before with some water droplets forming up by the flame arrester, but the dipstick has always looked like good clean oil. I'm ready to put this thing back together, but really dont want to put it back together if there are more problems I could address now.

Re: Small Milkshake found while fixing Vacuum Leak - ideas to fix?

Ayuh,.... My guess is, it's condensation build up...

Re: Small Milkshake found while fixing Vacuum Leak - ideas to fix?

Bond-o said:

Ayuh,.... My guess is, it's condensation build up...

Click to expand...

Thanks for your input. This would seem to suggest the next step should be to put it back together and go boating? Any way to avoid the condensation buildup in the future?


Any other ideas as to the cause of the small milkshake?

Re: Small Milkshake found while fixing Vacuum Leak - ideas to fix?

tcgravy said:

Thanks for your input. This would seem to suggest the next step should be to put it back together and go boating? Any way to avoid the condensation buildup in the future?


Any other ideas as to the cause of the small milkshake?

Click to expand...

Ayuh,.... Never shut it off,..?? move to a low humidity climate,..??

The valve covers, 'n the top of the motor, cools sooner that the core of the motor, 'n humidity from within the motor, condenses on the cool surfaces...

Ya, the fix is Run it, hard enough to build heat in the oil...
The water will steam off...