Fordracer Posted July 19, 2013 Share Posted July 19, 2013 I have a 1994 7.3 IDI non turbo with 164,000 miles on it. The customer says while driving it everything is fine but when it sits for three months the coolant level drops a quart and the oil is a quart overfull with coolant but there is no oil in the coolant. He has pulled the heads and had them checked for cracks and none were found. I haven't seen this truck yet so I haven't verified it. The only thing I can think of causing this might be the oil cooler seals that seal up when the oil pressure is pushing on them but when there is no oil pressure the coolant pressure causes a leak into the oil or a cracked cylinder. When he had the heads off none of the cylinders showed signs of coolant wash. Has anyone seen this happen on these older 7.3's? Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted July 19, 2013 Share Posted July 19, 2013 Most likely cylinder wall cavitation errosion. 1 Quote Link to comment Share on other sites More sharing options...
lmorris Posted July 19, 2013 Share Posted July 19, 2013 Typically the oil cooler orings would either have an external oil leak or push oil into the coolant. It could leak coolant into the oil when sitting, but you would mostly get oil in the coolant first. I second the cylinder wall cavitation. Quote Link to comment Share on other sites More sharing options...
Jeff Clyde Posted July 20, 2013 Share Posted July 20, 2013 agree with the cavitation. Remember sending more than a couple to the machine shop for sleeves back in the day ! A good friend of mine owns a machine shop, and I would end up there at night helping to sleeve blocks for him. Quote Link to comment Share on other sites More sharing options...
lraffe1 Posted August 12, 2013 Share Posted August 12, 2013 I resealed an oil cooler last weak. Flushed several times and no new oil yet. I have also sleeved a 7.3 idi for pin holes in cylinder walls. However they were hydro locked or smoked. Quote Link to comment Share on other sites More sharing options...
Fordracer Posted August 12, 2013 Author Share Posted August 12, 2013 Thanks for the replies. The customer decided to try stop leak since he doesn't drive it much he doesn't want to put very much money in it. Quote Link to comment Share on other sites More sharing options...
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