Yesterday I pulled the oil cooler and replaced the orings following Cody's write up. Once the cooler was back in place I put the coolant back and headed to get new oil and filter. Prior to adding the oil I pulled the drain plug one last time and out came about 1/2 quart of coolant. This was after about 2 hours.
I figured that during the install an oring didn't seat right so I pulled it and did not see any damage to the orings, reassembled and re-installed. Replaced the coolant and left it sit overnight.

This morning I pulled the drain plug and there was a 1/4 cup or so of oil coolant mix. I believe that the orings must be seated correctly since there was very little in the pan this am, probably residual.

I assume that based on the fact the coolant got to the oil pan that it got there through the oil side of the cooler.

How much coolant in the oil does it take to get the foaming and ruin the oil?

Should I replace the old oil and run it to purge the coolant from the oil side of the cooler prior to putting in new?

Thanks,
Wink

 

When changing my oil cooler O-rings, I removed the block drain to thoroughly remove the coolant as to insure none spilled over into the housing during reinstallation. This is what may have happened since it was a fairly small amount the second time. Were you getting oil/water cross communication before the change?

 

Your assumption about the improperly seated o-ring is correct as to how this happened. To answer your question, though, it takes much less than 1% coolant to screw up the oil. Run several (at least three) "cheap" oil changes through the engine with cheap filters, changing the filter each time as well as the oil. Then put back your good oil and a good filter. Then, follow-up by changing that oil at half your normal change interval. Once you've gone through this routine, you'll be OK.

On the "cheap" oil and filters, use the absolute cheapest you can find, and the cheap oil does not have to be diesel rated, either.

I've been through this routine myself and my truck is running great.

What I learned in terms of avoiding any kind of repeat on my next oil cooler job is to use thin film of grease on the surface of each o-ring as well as on the entire inner surface through which the ring will be squeezed while re-installing the cooler heads. If you don't grease these surfaces, you are likely to make the o-ring "roll" instead of "slide", and the potential for improper seating is dramatically increased if the o-ring rolls between the heads.

 

I had lubed those rings pretty well but I guess there was something that went wrong. The 2nd time id did pull the block plug so that may have some impact as well? Changed old twice now and no signs of foam or scum on the dipstick or in the degauss bottle.. I think I'm good. I appreciate the info!

 

Instead of relying on dipstick or degass bottle signs, just let the truck sit overnight and then drain about half a pint from the oil pan, let it sit, and see if you get any coolant settling on the bottom of the jar. If there is no coolant... keep running. If you see coolant, run another cheap oil change through the engine. It takes less than 1% coolant in the oil to create problems.