Author Topic: I got oil in Coolant reservoir!  (Read 4183 times)

Offline achtung3

  • Motobrick Curious
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I got oil in Coolant reservoir!
« on: April 12, 2018, 03:42:37 PM »
Finally after 2 years of moaning and growning I got my water pump replaced.


I had first found out that I was getting some oil in the coolant reservoir and it was a layer of gray foam then I took to a "independent bow" mechanic and he said that it seem to be a bad head gasket and I would need to replace it, $$$$$$


I told him that I had to wait, and 2 yrs went by and I did a radiator flush and try to check for compression (not a mechanic) and could not figure out what the hell I was doing and gave up.
All I was told by other mechanics that I should have oil dripping out of the weep hole and none of that was happening, even when I poked the hole with a wire, so I thought that I would have to have the head gasket replaced.


I took the bike to a dealer and they checked and found out that it was the water pump bad, so I had it replaced and now it is fixed.


Many of you from this forum were correct, it was a water/oil pump and I just had my thrust in this "independent mech" Who came out right off telling me that it was the head gasket, and wanted to believe he was right but my conscious told me otherwise due to many of you experts. I learned another lesson even at this old age.


Thanks for all of you and I know this is the right place for information.
  • 1990 K75S

Offline Past-my-Prime

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  • Posts: 581
  • All of us are better when we're loved.
Re: I got oil in Coolant reservoir!
« Reply #1 on: July 17, 2019, 09:47:45 PM »
You are not alone.
Small bit of black sludge on top of the coolant. Just noticed it last week.
Also some oil seeping out the oil pump for a few months so I'm thinking a oil / water pump rebuild is in my near future.

I found this post looking for "coolant" because my bike seems to be running hotter, fan and overtemp light come on at the same time.

Next steps:

refresh oil and water pump
flush radiator
check thermostat

Any concerns of this resulting in catastrophic failure with a planned 1,400 mile ride?
  • North Shore of Lake Superior (in my garage)
  • BRICK: 1989 K75 RT - Rocinante; NON-BRICK: 2007 F650 GS Dakar - Betty Blue

Offline Laitch

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Re: I got oil in Coolant reservoir!
« Reply #2 on: July 17, 2019, 09:54:45 PM »
Any concerns of this resulting in catastrophic failure with a planned 1,400 mile ride?
If the fan is cycling more than usual and the overheating lamp lights up, you have enough failure right now without waiting for it to be catastrophic. Rebuilding the combo pump should be undertaken soon and the process and its pitfalls thoroughly understood before then. It generally requires several new parts besides the seals if it hasn't been restored previously. A thorough coolant flush and replacement will follow.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline Past-my-Prime

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  • All of us are better when we're loved.
Re: I got oil in Coolant reservoir!
« Reply #3 on: July 17, 2019, 10:07:23 PM »
Thanks Laitch! Point well taken. I'd rather not be 700 miles from my home looking for a U-haul to get back home and will take the time to address this this weekend. Also don't want to wreck the bike. I may have to defer the road trip. . . was planned for the following weekend.

Re: the overheating / sludge in the overflow tank, I'm going to do a stepwise approach:

-First flush and clean the cooling system
-then refill with prestone/distilled water mix
-then see whether it cools better or not

The loss of oil at the pump worries me a wee bit but it's drips on the floor only and no change in the level in sight glass beyond the usual variability that you see on this bike.

If fresh coolant gives me the brown sludge then I'll have a better idea that it's oil. It could be degrading coolant - it's been a few years for this maintenance task.

I have a number of necessary overdue maintenance matters to attend to on this bike that I've had for 23 years and taken for granted.

Next on my list is spline lube. Then check valve clearances. Then flush brake lines with fresh DOT 4. What I need is a work holiday!
  • North Shore of Lake Superior (in my garage)
  • BRICK: 1989 K75 RT - Rocinante; NON-BRICK: 2007 F650 GS Dakar - Betty Blue

Offline Laitch

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Re: I got oil in Coolant reservoir!
« Reply #4 on: July 17, 2019, 10:57:48 PM »
The loss of oil at the pump worries me a wee bit but it's drips on the floor only and no change in the level in sight glass beyond the usual variability that you see on this bike.

If fresh coolant gives me the brown sludge then I'll have a better idea that it's oil. It could be degrading coolant - it's been a few years for this maintenance task.
It isn't likely to be Hershey's syrup but regardless, coolant that turns brown is degraded coolant that will fail to serve its purpose.

Your moto is overheating! You keep taxing your moto's engine by running it into the overheating zone and a cascade of bad juju might follow. The fan should prevent overheating in a functioning cooling system but your moto's isn't. Surely, flush and replace the coolant. That won't make any difference to a leaking seal though, regardless of where it drips. The moto should be off the road for maintenance.

You seem to acknowledge letting maintenance slide. That's easy to do when one of these motos runs well. Now the clock has struck midnight. Don't let your coach become a pumpkin by means of futile positive affirmation. :giggles
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

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