Join Date: Nov 2015
Location: Antioch Florida
Coolant in Oil
The model is a 2016 with a previously installed ThermoBob2, plus DeCalifed and DeAIS'd. Yoshi slip-on. It has about 15,000 miles.
Although there are several posts on this general topic (milky oil), they largely seem to be inquiries about observations that owners have about their site glasses. In my case, I have coolant entering the oil in the crankcase and I have oil in the coolant, both determined by draining the oil and coolant separately. The oil and coolant separate with the oil on top. When initially drained the oil looked foamy off-white; then separated into the two components. When the coolant was drained, several large oil spots floated in the coolant.
I have just completed a top end replacement (2013 Cylinder Head, Cams and Valves) after the decompression assembly (aka KACR) on the exhaust cam literally exploded...massive damage. I completed the top end replacement and believe everything was okay. It ran, I rode it around for two miles. However, I had to take it apart again to re-shim the exhaust clearances. I waited on the clearance adjustments until I was sure my used top end actually worked and that's when this new frustration started.
When I put everything back together today after reshimming, the bike started up fine, sounded great; it ran for a couple minutes when I heard a subtle pop or some noise; enough to turn the bike off and snoop around for the cause. I quickly noticed that the oil behind the sight glass was milky white. I had no other observations. I then drained the oil and coolant and started over with fresh fluids. The bike sounded and run fine (did not ride it, just listened, no funny noises)...but I had the same result..milky oil and oil in the coolant.
So bottom line, I have coolant mixing with oil where the oil belongs...and...oil mixing with the coolant where the coolant belongs. This strikes me that it has to be the oil seal behind oil pump (the one inside the case cover). That's the only place that the oil/coolant can go back and forth between crankcase and coolant channels. Do you agree? Or, do you think there is a way that this condition could have arisen from a blown head gasket (I admittedly used the 2016 head gasket in the rebuild)? Or is there possibly something else?
Thanks in advance.
Edit: The 2013 Top End Components were represented to have 5,400 miles.
Last edited by Bill10; 10-21-2018 at 08:39 PM.
Reason: Additional Information Provided