I have a Detriot engine that has a lot of blow by mechanic said some det,engine does that. its a 430/500. Also thinking about pulling flabed,my wheelbase is239,trans 10 speed with 3:90 ratio just wondering would that be good spec since a lot of load will be heavy.. I use 1 gallon of oil between oil changed 12000 miles I changed oil every 15,000. Avg about 6.3 miles per gallons, Thanks

Is the blowby coming out of the bottom tube? I have seen Detroits that test good on the Dyno but still have alot of smoke coming out of this tube. It may be a failing air compressor.

Yes it is coming from the bottom tube

We got that same motor/rating with the some problem. It started when the coolant system sprung a leak and the motor ended up severly overheated. That was over a year ago and it hasn't gotten worse. Motor has no torque at low end though - don't know if it was OK before. Very unpleasant motor to drive, if it didn't have a 13 speed you'd have to rev the crap out of it to keep from falling off the low end of the torque curve when you shift up. Much prefer our m11/330hp tractor - that's how bad it is :shock: ! Our detroit 470hp/1800rpm tractor has plenty of torque down to 1000rpm but that 430/500hp/2100rpm detroit just has no guts unless you get it up over 1200rpm and then it takes forever for the turbo to spool up :cry: .

roadranger Check your intercooler for leaks (have it pressure tested), sounds like that may be your problem there.

Yah, I suspected that is the place to start - but it ain't my truck and the boss likes to wait until something gets really bad to fix it. Also the MPG sucks, I only get 6.25 out of the aerodynamic truck (Int'l Eagle condo w/side extensions and 13 speed) with this 500 detroit where I get 6.75 out of a less aerodynamic truck (Ford Aeromax w/wing and 10 speed) with a 410 cat - both 3.70 rear ends. The Detroit in the better truck should be at least .25 better, not .5 worse! :shock:

What exactly is the intercooler and what is it purpose, would like to know before I carry to have it check. The blow by is a white smoke. Thanks again

Actually I think he was talking about it being a possible reason for my lack of low end torque - can't imagine how it would cause blow-by. Anyways the intercooler takes the air compressed by the turbocharger (which heats it up big-time) and cools it down 300 degrees or so. Looks liike a radiator placed in front of the coolant radiator. Cooler air has more oxygen per volume so the engine computer can inject more fuel for more power if the air is cooler. If there is a leak the pressure doesn't build as fast as the RPM's come up so the computer won't inject as much fuel at lower RPM's as it would normally which give you the low torque I'm experiencing.

Blow by can also be a sign of worn piston rings.

By the way, my blowby is so bad that I can't leave it running without folks coming up to me to tell me my truck is "overheating" :shock: