Do I need overhaul? Detroit 60 series 12.7

Same here.

 

My Detroit has, at times so much blow by, Ive had people tell me my Trucks on Fire!!! 1.2 mil on an OH. I ran a tube to the rear of Truck. I just changed oil. Added 1 qt of Lucas, 30 at idle, 50 at 1400, Blocked off breather tube about 90 % for first 25 minutes, had pressure up to 53 lbs. to check new rear main seal, before installing trans.Ran it another 20 minutes,Got a little warmer than normal operating temp. No blow by what so ever. It’s cool outside 58 degrees. No humidity, I Seems to have something to do with it. Hot humid days, older oil, lots of blow by. It’s hard to believe your engine would still be running with over 2 mil, if it wasn’t overhauled. Not impossible but rare.Usually they blow s head gasket and drop a liner, or slowly blow head gasket, leaking down the passenger side of block. Around 900-1.5 mil. Maybe the guy got lazy and let oil intervals increase, and then it sat a while before selling it. I’d change that oil a 9 or 10 k. At least 3 times. Use Lucas 1 gal. And add a gal in between. Run it hard, 1600 - 1700 rpms occasionally. Might just clean it up, and get the rings sealed up better.

 

You’ve checked a lot of stuff, make sure the dca nitrate levels are correct in the antifreeze. Cheapest PM, to avoid an OH.

 

I see 8 gallons added in 8300 miles, that’s a lot. It’s going somewhere. Maybe compressor or turbo. Both of those can also cause excessive blow by. Each has to be isolated during blow by test. Compressor, I believe you disconnect output hose. Turbo, I believe you disconnect drain tube. Just a thought. It’s a mystery, for sure.Mine being bad, and high mileage, I’ve checked, replaced both, still has a lot of blowby. My case, I suspect a broken piston ring, won’t know till it’s overhauled. I also wonder if it’s possible, that rings are floating around, sometimes getting gaps lined up occasionally, causing it to be worse, as it comes and goes. No one has ever given a reason for 12.7 blowby. Just “They do they” Lol. Very frustrating

 

Then get compressors checked, bad rings, in compressor can put pressure ( blowby) into crankcase. Causing engine blowby. Disconnecting stainless steel hose on top, Look for a change. Hard to see, I tried on mine. Seemed to make a difference. But didn’t, compressor was original anyway, But with a manometer hooked up, a shop can tell if compressor is causing it. 2 gallons is still quite a bit to burn @ 8300 miles. Also can be a bad compressor, pumping oil into air tanks, lines. It would be a lucky break, if it was only the compressor, not wore out engine. I’m not sure, but your dunk seemed a little low on HP. Maybe someone else can verify what normal hp to the wheeled should be. I still suspect Truck was sitting a while before you got it. Just a possibility. I really don’t know, just guessing.

 

I should add, my engine with 1.2 mil on OH, has been using 1 gal every 2400 miles. Also had bad rear main, and rear cover leak, recently fixed, haven’t ran it yet. I’m curious to find out how much it’s actually using, will try to remember to post info in future. Mines just wore out.Still has decent power, got to keep oil in it, and avoid getting too hot.Thats a Recipe for disaster.

 

I was thinking, maybe the rings aren’t sealing up good. Just an idea, oil usage may decrease, after you’ve ran it a while, and the rings seal up good. Everything gets sticky when they sit, problems I personally have had are, pitted wheel bearing, frozen ( rusted ) 5 th wheel slider, wiper motor, hvac blower motor, rusty door hinges. dry wheel seals, alternator gone bad. Any time an Old Truck sits too long, expect something to go wrong, Mines been sitting 6 weeks, air conditioning quit. It was working fine when parked. Batteries died from being old and a recent heatwave did them in. Won’t be surprised if my first week out, the alternator goes bad, or the starter, as they’re both old. Delvac vs Rotella?? Historically Rotella for Cats, Mobil Delvac for Detroit’s. Years ago, I had a Cat, When it started using oil, many told Me switch to Delvac, Lol. I did for a while, Seemed to help a little bit, who knows? Now I hear Switch to Rotella for a Detroit!!! Lol. Makes Me wonder if the different detergents, additives, etc. of each, helps to clean the old sludge of the other. Who knows?? Bottom line, I would run it, keep oil in it. Change it 2 or 3 times around 10 k. Hopefully that clean it up, and loosen the rings up, letting them get sealed up good again, It might help. Then keep it changed at 15 k. Detroit’s recommended interval. Maybe the rings or just one ring is stuck or sticky, or even broken, but the engine will still run long time, I would give it some time, work out any other bugs, that may be lurking, from sitting up. Before spending a bunch of money chasing Demons.If it starts mixing oil and antifreeze, or the coolant disappears, ( through the exhaust), or coolant starts building excessive pressure, ( from a bad head gasket,or cylinder sleeve dropping down, or a cracked head,) Then an OH is probably due. But for now, as long as oil pressure is good. I would wait, give it a chance to seal up. You never know. Yeah, You probably could benefit from an OH, and a new Trans, and rear ends, and a Whole new Truck, Lol. I wouldn’t throw money at it, as you never know what other repair is right around the corner.