I just picked up a stock dual oil cooler kit from a forum member and wanted to flush/clean them out as a piece of mind before I install them on the car.

Does anyone know of a good method to do this? I could just hook some air up to it, but I think a fluid would be more efficient.

 

Just use water. I had a needle bearing failure and the easiest solution was to just alternately blast in both sides with a garden hose. Drain it at best you can or blow it out with air.

If you want you can use cheapo oil on the first fill and do a 50 mile oil change. You'll get most the water out that way.

 

Wondering if shops that service auto trans. would have a way to flush them.

 

Maybe your local radiator shop?

 

I'd go with ultrasonic cleaning. There are places that specialize in this stuff, e.g., these guys.

 

Apparently pouring in a bit of petrol (or just general degreaser) and shaking it around works well

 

Don't do this.

Fill 3/4 full with lacquer thinner, shake, drain, blow out with air. Repeat until runoff is clear and debris free. If you find much debris at all consider have them sonic cleaned professionally or dont use them at all depending on the debris.

 

Here is what I do.

Remove the thermostat from the oil cooler and use a silicone plug or vacuum cap to plug the bypass port between the inlet and outlet holes at the bottom of the cooler then reinstall the tstat. If you don't do this you are only flushing the bottom passage and not the cooling rows themselves. Grab a 5 gallon bucket and fill it at least halfway with solvent...mineral spirits, diesel, kerosene, etc. Position this under your work bench or whatever you are going to prop the oil cooler up on. Grab an old fuel pump, hook wires to it and those wires will run to a battery. Run a hose from the fuel pump to the oil cooler. Stick the hose in one of the holes, use another length of hose from the other hole back into the bucket, hook up the pump to the battery, and flush the cooler for about 30 minutes. Then switch the hoses so you flush the other way and run it 30 more minutes. Dont forget to pull the thermostat and remove your bypass plug. Blow the cooler out thoroughly with compressed air.

I've gone farther with hookups to flush the cooler setups with the existing lines and coolers still mounted in the various rotary cars I service, and I have an inline oil filter between the fuel pump and the cooler to catch anything that gets flushed out into the bucket so it isn't pumped back into the coolers. I have to do this routinely to the rx8s that spin bearings and pump the coolers, lines, and oil pan full of metal shavings. No failures so far.