Whats the best way to clean/flush a Stacked Plate "Donut" type of Oil Cooler
 

I am working on an oil cooler project and before I flush my stacked-plate type of oil cooler (oil circuit, not coolant circuit) I want to know if there are any proven methods or solvents to use. The cooler was off of running low mileage engine with no apparent metal debris (from what I can see), I just want to get the USED oil residue out of it. Any suggestions ?

I was going to just used brake cleaner and maybe flush/pump some Kerosene based cleaner through it ?

Any suggestions ? see pic of cooler type.

The thought of boiling it in water occured to me but I fear this could plug it up.

Thanks

I cleaned mine with a good degreaser and hot water. After a few days, I poured alcohol in it to help any water evaporate as I pumped air through it. Then flushed with motor oil until clear.

Bob, I used the basic degreaser (Dawn) and hot water last night and had pretty good results. Then filled with WD40 to disperse the water and used shop air to flush and repeated with wd40 again. I only observed oil exiting so far, no other debris. The cooler is mostly made of stainless steel so thats a plus. (perhaps that explains the $1200 price tag from dealers)

I also realized (Ah-Ha moment) after doing the above that since this cooler has the oil filter mounted directly to it, why not use the filter to help with this task ??? With the new filter in place, I assembled a small bench re-circulating rig to simply circulate fresh engine oil through the unit (Mity Vac pump fittings came in handy) thereby allowing the oil filter to capture all the other dirt that may still remain. I am trying to find a cheap electric transfer pump to circulate engine oil (2-3 gpm) through it for a few hours and then see if it works. This way after the bench recirculation is finished, I will just toss the filter in the trash and should have a cooler that is pretty near clean enough before fitting it to my engine. This would not be so easy with a fin and tube cooler. Since I dont plan to heat the oil up during this, I may add a little oil detergent to the engine oil to help the cleaning. I can still see small deposits on the outlet side of the cooler that I want gone. I'm just being a bit over cautious *nal here because engines cost so much. I'll report back if this works.

Whats the best way to clean/flush a Stacked Plate "Donut" type of Oil Cooler
 

would there be a problem with leaving bulk oil outside even if you are using it so maybe there might be an air space in there?

As long as it's a closed container, it should not be any problem.