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Discussion Starter #1
I hope some of the experts on the forum can enlighten me as to how the oil flows through the cooler on the 2600. When the thermostat is closed, is ALL the oil stopped from flowing through the cooler? When the thermostat opens, does ALL the oil then flow through the cooler, or only some of the oil? When a fresh engine is installed in the car, it would seem no oil will flow to the cooler until the thermostat opens and then the cooler would fill, thus lowering the oil level in the sump until more oil is added to bring the level up to the "full" mark again. Does the cooler receive oil before or after the filter? I appreciate the help in understanding the oil flows through the 2600 motor.
 

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Although I’ve not lived with a 2600, I actually have a complete 2600 oil cooler with related adapter and hoses I intend to install on my 2300.

In any case, thermostat controlled oil coolers generally operate the same. When cool, no oil is bypassed through the cooler. As the oil warms, the thermostat very slowly opens diverting some oil through the cooler. The onset of the bypass is slow enough that you will not have a precipitous drop in pressure. Although I’ve not confirmed with the 2600, generally coolers are in the return, not feed, line in any case.

If you start with a new engine, you can always choose to pre-fill the cooler and lines with oil. That’s probably more effort than it’s worth. I would simply go through the normal new-engine commissioning steps, and add whatever oil ends up being taken into the cooler, and filter if you didn’t refill it as well.

I always do a fairly early drain and refill with fresh oil after commissioning a freshly rebuilt engine.
 

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Discussion Starter #3
Don: Thanks for the reply. If you have a 2600 Adapter unit, can you determine if, when the thermostat is fully open, that ALL the oil is routed through the cooler? With the 2600 being a wet sump engine, the cooler has to be in the "feed" line from the pump. Hopefully your examination of the adapter unit will tell us if the cooler is before the filter or after the oil is filtered. Really appreciate your response.
 

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The adapter unit, as you probably know, fits between the engine block and the filter.

I misstated what I intended in my previous post. Of course the cooler is in the pressure side. What I don’t know is where it is in that loop. Do you have all of the manuals for the 2600? If so, perhaps you can find the flow schematic? I don’t have all those manuals.

Is the cooler before or after the filter? I dunno.

Meanwhile, my opinion is that the thermostat is unlikely to send all of the flow to the cooler. This would be a treacherous design. If this was possible, a failed-open t-stat could cause all of the cold oil to travel through the cooler on startup. That could result in low oil flow and pressure during a very cold start.

BTW, the t-stat for the 2600 is the same as used on the Montreal. Not sure that info helps, but there might be another schematic to study.
 

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Discussion Starter #5
Don: I do have all the manuals, and have not found a lubrication diagram. I agree with your thought that not ALL the oil flows through the cooler when the thermostat is open. However I am just not sure and hope that someone else here can provide the accurate information on the oil flows.
 
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