possible coolant leak

[byker]

On the last oil change on my 87K100rs (115,000 km's), the oil level in the sight glass rose after a short ride. I think that there may be a coolant leak into the block. The overflow for the rad was down a 1/2 inch on the outside sight hose. The bike has the original oil/water pump and it is dry. Two thought come to mind. One is that there is a blown head gasket and second, the oil/water pump is suspect. Your collective thoughts and remedies are appreciated.

[manicmechanic]

I'd drain the oil and check its condition. The next thing I'd do is pull the spark plugs to check for contamination on any of them. If you have a head gasket leak you might see some "smoking" from the exhaust, mostly white. A compression test may also point in the correct direction. I've heard of car mechanics applying air pressure through spark plug holes and looking for bubbles in the radiator. However, before resorting to that, ensure the pumps' weephole is not plugged. Have you noticed any other problems/symptoms?

[bmwmick]

On the last oil change on my 87K100rs (115,000 km's), the oil level in the sight glass rose after a short ride. I think that there may be a coolant leak into the block. The overflow for the rad was down a 1/2 inch on the outside sight hose. The bike has the original oil/water pump and it is dry. Two thought come to mind. One is that there is a blown head gasket and second, the oil/water pump is suspect. Your collective thoughts and remedies are appreciated.

If you really have coolant in your oil, the oil will look like coffee with cream.
:cry Not a good thing for bearing lubrication.

Mick :type

[deilenberger]

If you really have coolant in your oil, the oil will look like coffee with cream.
:cry Not a good thing for bearing lubrication.

Mick :type

As Mick said - coolant in the oil will typically give a frothy look to the engine oil.

One thing to check - the water/oil pump are a combined unit. Betwen the two pumps is an empty space with a weep hole to allow any leakage OUT so it doesn't contaminate the other liquid.

The pump is right at the front of the engine, and the hole is right at the bottom center of the pump. Stick a piece of wire up into the hole to make certain it hasn't plugged up. I have heard of oil contaminating the coolant if the hole gets plugged (oil is under more pressure than the coolant), but I've never heard of it the other way round.

A drop of 1/2" in your overflow tank really isn't too significant if the engine is cold. I've seen that much variation frequently. What you want to check is the level when the engine is warmed up. I used a grease pen to mark the coolant level on the indicator when my bike is warm - that lets me keep an eye on it without temperature variations causing problems.

It also isn't uncommon to see a bit more oil in your sight-glass - if the bike is leaning even slightly towards the right when you view it, or if you filled the bike with it leaning even VERY SLIGHTLY towards the left.

How much oil did you fill it with? Just under 4 quarts brings it to the top of the window (which on a K bike IS the correct level - not the center dot as on oilheads.)

I suspect you're worrying about nothing - or at worst a leaking water pump. K bikes are not known for loosing head gaskets for no reason (ie - the bike overheating badly might be a reason, but you didn't mention this happening.)

Best,

[SweetT]

My K75 does this every time I change the oil. I wouldn't worry too much about it. If you did have coolant in your oil, your oil would look cloudy when you drained it, and you'd be blowing white smoke everywhere.

[drrider2]

Did the oil smell of gasoline? I have seen a leaking fuel injector or fuel pressure regulator cause that. :dunno