Here's a few pictures of removing the oil cooler. Now that I have the thing out, it is not obviously damaged, but I can easily see how it could be leaking anywhere along the many seams. I'm not sure how I'm going to pressure test it though, since there is no easy way to hook air up to it that I can see. I might try to make up some kind of jig, or I might just take it to the local NAPA/repair shop tomorrow and see if they can test it for me.

I have to say that there was a small amount of oil/coolant mix in the filter and galleries in the bracket. But there was more plain oil in there that had not been emulsified yet. Boy I sure don't want to have to pull that head...

 

i just pulled a head the other day. it wasnt all that bad. just make sure u have a cherry picker to get it out.

 

Except for the cherry picker, which I don't have, pulling the head is not what I'm worried about. The cost and time of the gaskets and trip to the machine shop for any warpage that I might find is what I can't afford right now. like any six cylinder, the head looks pretty straightforward to remove.

i just hope it's the oil cooler and that the used one i bought tests out ok. I am still trying to decide if I can afford a new cooler.

 

Just get a large rubber tipped ,air nozzle on one of the oil passages, and then a chunk of rubber, and your thumb, to hold sealing pressure on the aether port.
submerge it in slight soapy water and see the bubbles!......remember low air pressure.

I think why mine didn't show a leak the first time i tested it was because there was oil in the leaking area and the pressure was pushing out oil not air at the time!



Flash.

 

OK, here's what I came up with, after a few frustrating attempts. Indeed, the oil cooler has noticable leak in it, and it didn't take very much pressure to make it bubble..

yes, that is a wine cork, but it took some whittling to get it to fit. The "rubber" ball on the air nozzle is electrical tape wrapped around about a million times.

Ghetto Pressure Testing Jig for Cummins Oil Cooler:

 

great deal woodrat i have not worked on one yet excellent photo's. hope this works out for you. good idea on the cork. hope you had some pleasurable company over to help empty the bottle.

 

that's grate.......now you don't have to concern you self so much about your head gasket!




Flash

 

Yes, that is good news. Now I just have to hope that the one I bought on ebay is not leaking as well! In the meantime, while I'm waiting for it to get here, I have a valve adjustment and rear brakes to do.

 

just wondering if anyone has used an external oil cooler and done away with the stock one. i bought the 11" x 11" for my gm6.2 to get it out of the radiator. never been much on oil and water mixing. just thought i could block off/bypass the one in the block and run hoses to one up front (if i can find the room ) or put a fan on it like the trans coolers run.

 

The way it is plumbed, it would be hard to bypass this thing. You would need to make a custom plate of some kind to replace the cooler, and it would have to have a nice big oil gallery in it too.

 

just kind of planning my conversion. just thinking out loud. those coolers even with a oil thermostat and hoses would come in at 250 bucks or so.

 

What's the conversion you are planning?

You would need some machine shop time for sure in order to make an adapter that would go where the cooler goes and have the galleries and fittings in the right places. I don't get the oil/water heat exchanger thing either, but it seems to be common enough in these industrial diesels, so I guess the designers know what they are doing. Still, given the unbelievable mess this created, I will be forever a little nervous about it happening again. At least until I can afford a brand new cooler, anyway.

the used one pressure tested fine, so I am going ahead with that since I don't have the dough to do otherwise. For what it's worth, the one that was in there was canadian made, and the new one that I got that came out of a 98, is US made.

Oil emulsified with water does not behave anything like just plain oil. the stuff flows like frozen molasses and doesn't wipe up easily, even with a little heating oil as a solvent. I am trying to get all that I can out before I put it back together.

I finally got the gaskets in today, have to go over to Astoria to pick them up. I tried FIVE different Dodge dealers after I got home. One found the part numbers and could order them, but wouldn't take my CC over the phone and ship them to me, they wanted me to come in IN PERSON to prepay the order. This was Tonkin in Portland, about 90 miles away. Three dealers couldn't even figure out what part I was looking for, and one of those insisted that I needed to give him the VIN of the truck or he couldn't even try to look them up. One argued that maybe the oil cooler had no gaskets since he couldn't figure it out. That's the one closest to me.. Lum's in Astoria knew what I was talking about and ordered them in overnight. Sheesh! What is the world coming to?

 

i wondered if cummins northwest might have had them? as far as my conversion i have a 78 crewcab dodge 3/4 ton 4x4 with a auto and gasser. want to install cummins with a fivespeed stick and the axles. went for a ride in Regs' dodge pu and it was a very nice ride.

 

Oil to water is better for us. The oil cooler acts like an oil heater when the engine is cold, and a cooler when the engine is working hard. It keeps the oil temp stable. An air to oil cooler will allow much wider temp swings and will cause the oil to warm up very slowly (or not at all) in cold weather. And cold oil is tough on bearings.

 

Nice conversion project. That would be my dream rig!

I figured those cummins engineers probably knew something I didn't...

Cummins in portland no doubt would have had the gaskets, but they are in Portland. I've got them now, so hopefully tomorrow I'll have the cooler back together and then I'll do the valves, and get the cover off for when the KDP kit gets here.