JoeH Posted May 11, 2021 Share Posted May 11, 2021 '95 rd688s with an E7-350. Horrible oil leak at the rear of the oil pan area, found 2 cracks in the old oil pan so we put a new one on; still leaking. Inside of the flywheel housing is dry. Book indicates there's an "isolated" and "non-isolated" oil pan setup. Do they use the same oil pan? Mine is the non-isolated setup, did the dealership give me the wrong oil pan? Hoping it's not related to the flywheel housing "Silastic" seal to the engine block... Could a flywheel housing-to-block bolt break or loosen and allow enough flex to crack the old oil pan and cause the new one to leak? 21,200+ hours. Any common problems in that area? Quote Link to comment https://www.bigmacktrucks.com/topic/66691-95-e7-350-oil-leak/ Share on other sites More sharing options...
theakerstwo Posted May 11, 2021 Share Posted May 11, 2021 Here is the way to find the leak.Wash it and get the oil off of the back of it.Run engine till its hot as you can get it and at about 1500 rpm hold your hand over th bottom of the blow/by tube and build some crank case pressure.Dont hold your hand over the tube too long but long enough to build some pressure.get under it with a good light and look for the leak.Wash it down again with brake clean and blow it dry and look some more till you find were its coming from.If it the flywheel housing to block leaking then you will see it from the out side.If its the pan gasket then you can see it from the bottom.The isolated pan uses a shoulder bolt and is a different size thread. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/66691-95-e7-350-oil-leak/#findComment-473738 Share on other sites More sharing options...
JoeH Posted May 12, 2021 Author Share Posted May 12, 2021 Sidenote, the part number on my '95 E7 oil pan gasket is the same as my '79 ENDT676. Mack really liked to keep things standard. I'll bet one of the oil pans from my 3 spare engines would have fit just fine, and saved me $2,000. But my daily driver gets what my daily driver needs, no screwing around to save a buck. Quote Link to comment https://www.bigmacktrucks.com/topic/66691-95-e7-350-oil-leak/#findComment-473741 Share on other sites More sharing options...
terry Posted May 12, 2021 Share Posted May 12, 2021 10 hours ago, JoeH said: Sidenote, the part number on my '95 E7 oil pan gasket is the same as my '79 ENDT676. Mack really liked to keep things standard. I'll bet one of the oil pans from my 3 spare engines would have fit just fine, and saved me $2,000. But my daily driver gets what my daily driver needs, no screwing around to save a buck. 2000. for a oil pan!! wow! terry used overhaul a engine for that! Quote Link to comment https://www.bigmacktrucks.com/topic/66691-95-e7-350-oil-leak/#findComment-473777 Share on other sites More sharing options...
JoeH Posted May 13, 2021 Author Share Posted May 13, 2021 It's looking like the oil pan gasket doesn't seal around the 2 bolts front and 2 bolts rear. Pressurizing it made oil pour out of the front around the oil pan reinforcement straps, where it wasn't leaking before. Didn't make it leak at the rear much, but we're going to pull the pan back off, smear some RTV silicone on it all around and see what happens! Quote Link to comment https://www.bigmacktrucks.com/topic/66691-95-e7-350-oil-leak/#findComment-473851 Share on other sites More sharing options...
JoeH Posted May 13, 2021 Author Share Posted May 13, 2021 Does anyone know if the oil pan threaded bosses in the timing cover and flywheel housing are open to the crankcase or if they're sealed? Quote Link to comment https://www.bigmacktrucks.com/topic/66691-95-e7-350-oil-leak/#findComment-473852 Share on other sites More sharing options...
JoeH Posted May 30, 2021 Author Share Posted May 30, 2021 Not sure how to add photos at the moment, but we found the oil leaks! There are 10 holes in the oil pan flange presumably for spot welds to hold the reinforcing strip in place. Well, someone never spot welded it, so oil was able to seep past the gasket at the front and rear. $2,000 for a part 90% complete. Quote Link to comment https://www.bigmacktrucks.com/topic/66691-95-e7-350-oil-leak/#findComment-474510 Share on other sites More sharing options...
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