7.3 oil in the coolant, o-rings, now what?

[TomsBeast]

After discovering a fair amount of oil in the coolant, I Replaced the oil cooler oil rings that were dry and brittle, and the oil filter adapter to block gasket (but not the forward adapter gasket, I pulled the cooler without disturbing the forward adapter). Did an oil and filter change just because.

The o-rings leaking is a pretty common cause of oil contamination in the coolant, according to the research I've done, especially a 22yr old 7.3. 30-60psi oil pressure pushes oil past the big o-rings that separate the oil system from the cooling system, in the oil cooler. I used Ford parts.

I got it back together, flushed with water and simple green 3 times, clear water, then dishwasher detergent 3 times. It's still pumping out oil into the cooling system. I'm using/loosing oil from the crankcase at the same, the dipstick shown 3 quarts low after (3) 10 minute drives and (6) soapy flushes.

I'm flushing by disconnecting the lower radiator hose into a bucket that catches 70% of the oily water. I would have expected after flushes to not have oil, but I've got just as much oil now as flush #2-#5.

I was pretty careful, wire brushed some rust away near the coolant to atmosphere o-ring (if that were leaking, I'd have coolant on the ground). I lubed up the o-rings at assembly. Cleaned the bores of the aluminum end adapters. Used new Ford o-rings and block to oil filter adapter gasket.

I'm about to pull my hair out, as pulling this thing apart is one messy, , and ugly, aweful job! Repair shops want 7-10hrs to do the job, most of which is the time to flush the customer's cooling system, I'd prefer to save the money, and don't want to admit defeat.

I've resigned myself to pulling it again, but what to check?

Out of desperation, I ordered a new Ford cooler, another round of o-rings, and both end casting/adapter gaskets.

What else should I be looking for?

Is ther another failure point that put oil in the coolant on a 7.3?

[Bbasso]

I'm at a loss for words, seems like you have done your research and I wish I could add additional info but to be honest I've yet to hear of such a problem.
Be sure to let us know on the solution, it might help one of us one day.

[arctictraveller]

I know little about the 7.3, but I do have experience with the same problem on a Lugger 6170. It too was the oil cooler o rings, but once replaced and as you did, flushed with soap (dishwasher detergent actually) and run, there was still some residual oil. It took a long time to get it all out, but it sounds like you have a continuing leak. I would suspect the cooler it self as you do. You could pressure test your original one to accurately determine if that is the problem. Just block off one end of the coolant passage, adapt a way to add air pressure to the other side, then submerge the entire thing in water and look for bubbles. Just don't over pressurize, I once did that with an exhaust manifold, and it exploded resulting in a bunch of stitches. I was really lucky it wasn't worse. If the cooler tests ok, where else does coolant circulate with oil? Best of luck..

[BroncoHauler]

I had a brand new, factory oil cooler on my 7.3 come with a bad weld, and ended up with a grayish, slimy sludge in my cooling system, so it could be the cooler itself.

Ford ended up paying my local shop to clean things back up (or least that's what my shop was asking Ford to do). This happened right before I moved out of CA, so I lost track if it was resolved between the shop and Ford. Nothing out of my pocket, except a little more downtime.


Herb

[TomsBeast]

I've got today dedicated to 'van work day'. I spent Wednesday evening after work removing the entire cooler, including the front end casting this time.

Those front oil cooler bolts require some creativity, an 18" wobbly, a 3" extension with universal, 24" of Rube Goldburg socketry I tell ya!

The 7.3 cooler removal job was equally messy the second time

My new eom Ford cooler center section, orings and end casting gaskets arrived, but I'm having second thoughts about just throwing them on a praying I've fixed it, as the flushing procedure takes 6-7 hours, and is an oily wet mess.

I'm going to build a bench top test set up, that uses block off plates, air pressure, and a tub of water to first isolate the current leak

[arctictraveller]

Originally Posted by TomsBeast

I'm going to build a bench top test set up, that uses block off plates, air pressure, and a tub of water to first isolate the current leak

Just make sure you don't over pressurize it. As I said before I did that once with a marine exhaust manifold, and it exploded, sending jaged, razor sharp chunks of cast iron all over the shop, including impaling one in my finger. Be sure to let us know what you find.

[TomsBeast]

Originally Posted by arctictraveller

Just make sure you don't over pressurize it. As I said before I did that once with a marine exhaust manifold, and it exploded, sending jaged, razor sharp chunks of cast iron all over the shop, including impaling one in my finger. Be sure to let us know what you find.

Yep that's a good lesson, lot's of stored energy in compressed air.

I spent most of the day rigging up a regulator, making the seal off plates, and a tie bar fixture to keep the end castings on.

I'll test today

http://www.sportsmobileforum.com/for...cture34332.jpg

[TomsBeast]

After spending more time understanding the coolant and oil passage circuits, I was able to conclusively get a 'positive' test for the old cooler having an internal leak (between the oil side, and the coolant side. Then, with the new cooler center section, re-using the newish o-rings and old end castings, the new cooler tested negative, no-leaks.

Now I'm more confident that the new oil cooler center section will cure oil getting into the coolant, no more chocolate milkshake mess

[BroncoHauler]

Congrats!


Herb

[arctictraveller]

It's always satisfying when you are trouble shooting and get a positive indication you have found the problem. I do wonder why the tube section corroded enough to leak, perhaps at some time the coolant was compromised? Or was it a bad solder joint or weld? Anyway, glad you found the problem...........