Shlep Posted May 27, 2009 Share Posted May 27, 2009 A 2003 F350 rolls in today and the customer tells me he's got oil in the coolant bottle so I figure a 6.0 with a blown cooler but walk out to look see and it's a 7.3 so I figure either I have a failed gasket or a cooler but figured I'd see if anyone has had this and what was the cause. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted May 27, 2009 Share Posted May 27, 2009 It has always been oil coolers for me. Quote Link to comment Share on other sites More sharing options...
GregKneupper Posted May 27, 2009 Share Posted May 27, 2009 I have always replaced oil coolers when I see this but I have been told that it is the orings that fail and cause it. I sell the cooler though because I do not want to take the chance of the orings not fixing it. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted May 27, 2009 Share Posted May 27, 2009 We've seen many times where it was the cooler, and several times where replacing the cooler did not fix it due to corrosion in the end casting where the o-rings ride. Once we made the decision to change both castings and the cooler bundle when this complaint occurred, we never again had a comeback. If you don't change the end castings, inspect them VERY closely after bead blasting. You will likely find roughness from cooling system neglect (no, really?) that will compromise the o-ring's ability to seal from the bundle to the end casting. Good Luck! Edit- change "one" to "once". Quote Link to comment Share on other sites More sharing options...
Shlep Posted May 29, 2009 Author Share Posted May 29, 2009 Thanks guys and Bruce thats exactly what I expect to find "if" the customer returns for further diag. Quote Link to comment Share on other sites More sharing options...
eastendpowerstroke Posted May 29, 2009 Share Posted May 29, 2009 Be real careful if you replace the caps the new ones are shit. I just replaced a cooler and the front cap because of an external oil leak. GUESS WHAT I HAD NEXT WEEK???????? Thats right oil in the coolant. My parts guy ordered 4 front caps and I had to use the best of the worst.the photo can't show how rough the casting realy is right where the oring sits.(edit) BTW that cap is brand new it was only on the truck for 4 days Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted May 29, 2009 Share Posted May 29, 2009 Dave that picture isn't too bad. I can see the rough area pretty good. What's even better is that this cap was installed and the o-rings left marks that you can see... see the intersecting area of rough casting and o-ring. Quote Link to comment Share on other sites More sharing options...
Steve Mutter Posted October 20, 2011 Share Posted October 20, 2011 I have one right now. It's an 2003 school bus with the 7.3 and lots of oil in the degas. We don't have that pressure tester for the oil cooler but I kind of put pressure to it and I did not find a leak. Other then the rough casting in the headers, there isn't anywhere else that could cause oil to get into the cooling system ? or is there ? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted October 20, 2011 Share Posted October 20, 2011 They frequently don't show leakage when testing even when they are bad due to the fact they can leak very slowly. We did a lot of these and resolved ourselves to changing the bundle and both end castings to avoid comebacks (which we had a lot of until we changed all parts). The area in the casting where the o-rings ride is always pitted from coolant neglect, allowing the seals to seep. Good Luck! Quote Link to comment Share on other sites More sharing options...
Steve Mutter Posted October 21, 2011 Share Posted October 21, 2011 I pulled them apart and found pitting in the sealing surface, so I am going to replace them both. Wow! there not cheap !!!!! Quote Link to comment Share on other sites More sharing options...
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