TOPIC:

Hello all.

I am not familiar with oil coolers at all. The zn1100 has a Lockhart oil cooler on it. From what I have read there is supposed to be a thermostat in these which dictates when the oil will actually run through the cooler. How would I confirm this is working correctly?

Secondly how do I make sure the oil gets drained from the cooler on an oil change?

Thank you.

No themostat unless someone installed one as an option, they are pretty bulky and you cannot drain out the oil in the cooler unless you take off the hoses and let it drain. I wouldn't worry about either one really.

I have had one on my KZ900 for years and never drained it other than whatever dribbled out of it. It leaves a bit of used oil in the systen but changing every 2,000 miles keeps most of it fresh enough.

Take the cooler off, flush it with diesel or let it stay soaked in diesel and then let it dry?

You worry about nothing.

The oil cooler is merely a safety device which prevents the oil from getting close to boiling point and loosing its lubricity. Its main funtion however is removing the extra heat produced at the wet clutch...only spot where oil is used as coolant...hence the word 'wet'. no need for any thermostat....when the motorcycle is not moving, the oil cooler has no effect whatsoever.

...unlike most people think, the oil cooler does not help cool the engine. It is an OIL cooler, not an engine cooler..and has nothing to do with the fact the engine is air-cooled. Even high performance liquid cooled motorcycles have oil coolers...where they take care of the same thing....the wet clutch. Look behind the pipes of a the newest Yamaha FZ-10 (MT-10) below the radiator...….that is an oil cooler.

...when draining oil, gravity takes care of bringing the oil down

..best analogy in a car is the autotranny ATF cooler, even though in a car the transmission and engine are separated. No one worries about thermostat or draining ATF from cooler in a car.

...like with the autotranny, the motorcycle will work perfectly well without the oil cooler, but it certainly contributes to the longevity of whatever machine is on.

I don't agree, The cooler oil has an effect on every part of the engine in which it passes. The primary function of oil is cooling not lubrication. In a car the tranny fluid is sent through it's own cooler in the radiator. It's purpose is to keep the fluid at the optimum temperature so it will flow correctly in cold and not burn in high heat situations.
If I lived in a colder climate I'd have a thermostat. I might still get one but so far I haven't had to.
Steve

I have run oil temp gauges, oil coolers, and oil thermostats on both of my Zs for decades. By the way, I live in Florida. During cold winter days, oil temp might stay below 160 degrees F for the duration of a 50+ mile ride. During the summers, oil temps often easily exceed 240 degress F and beyond in stop and go (mostly stop) traffic.. An oil thermostat helps especially during the winters here and/or during short rides - I always shoot for an oil temp of 180 degrees F to get most of the moisture out of the engine. Been using AMSOIL 10W-40 MC oil for a long time which can help with the internal rust issue I understand, among other things. Plan to install 4" Derale fans behind each oil cooler some day to reduce oil temps during stop and go traffic durring the many hot days of the year. I recall being in stopped traffic during Bike Week with hundreds of fellow motorcyclists while watching my oil temp gauge on my '73 Z1-900 read 220+ degrees F with air temperature at ... 32 degrees F.

Dime wrote: I am not familiar with oil coolers at all. The zn1100 has a Lockhart oil cooler on it. From what I have read there is supposed to be a thermostat in these which dictates when the oil will actually run through the cooler. How would I confirm this is working correctly?

Derale made a line of coolers with a built in thermostat. I have a picture of the box for the kit that I had, but I don't have a picture of the insert that showed a diagram of how the thermostat worked. But basically there is a metallic finger in the input side tube, and when the oil is cold the finger acts to block the upper cross tubes on the cooler, diverting oil into the single bottom cross tube. When it warms up, the finger (bimetallic strip) bends back allowing oil to flow through all cross tubes.

I don't know if Lockhart made a cooler with the same setup. Maybe try looking down into the inlet port to see if there is anything that would divert the oil flow.

Oil coolers DO help cool the engine, not just the clutch. Consider this - many motorcycles that used dry clutches, such as Ducati, Guzzi, etc. still used oil coolers. If the oil cooler was only intended to cool the clutch it certainly would not be used when the clutch is not bathed in oil. The oil extracts heat from the engine as it flows all over internal engine parts. Then the oil is cooled so it can continue to extract heat from internal engine parts.

If my bike had an oil cooler I certainly would want it controlled by a thermostat. Otherwise, it would extend the length of time the engine would take to reach proper operating temperatures. This would be especially true when the air temperature was cool. Ed

hugo wrote: ...unlike most people think, the oil cooler does not help cool the engine. It is an OIL cooler, not an engine cooler..and has nothing to do with the fact the engine is air-cooled.

I don't really agree, but I admit that an oil cooler may not be very efficient for an engine like the Kz that was not expressly designed to be oil cooled.

However, your statement is certainly not true for the air/oil cooled Suzuki GSXR engines. These engines were explicitly designed to use oil to keep the internal parts of the engine cool.

en.wikipedia.org/wiki/Suzuki_Advanced_Cooling_System

"The SACS system uses high volumes of engine oil aimed at strategic points of the engine, like the top of the combustion chamber, which are not typically well served by air cooling alone. In order to provide enough oil for both cooling and lubrication, the system uses a double-chamber oil pump, using the high-pressure side for lubrication of the parts (crankshaft, connecting rods, valvetrain), while the low-pressure, high-volume side provides oil to the cooling and filtering circuit. The oil removes heat from hot engine parts through direct contact, is pumped away and subsequently routed through the oil filter, followed by routing through an oil cooler before being returned to the main sump."

If memory serves, Lockhart sold its Model 500 that had a built-in thermostat.