2004 DT 466E HT Excessive Blowby

[Josh S]

Hello, I have a 2004 International RE300 with the DT466E HT engine that has started to produce a substantial amount of white blowby – especially when pulling a long grade. It produces enough smoke to leave a haze visible in the mirrors. I believe it is time for me to tackle my first engine rebuild, but I want to make sure I am not missing anything simple. To me, the bus seems to have plenty of compression (no extended cranking times when starting when cold). I run shell Rotella T6 15w-40 and have tried Luca’s oil additive with no success. The smoke coming from my exhaust pipe is clean (not white). All the white smoke is coming from the blowby tube. My oil is clean (no coolant).

Engine Details:
• 2004 DT466E 225hp High Torque (Pre-EGR)
• The engine has 210k miles and about 12k hours
• I am running a power-hungry performance tune set to 300hp
• I have a EGT sensor after the turbo and I keep the temp below 1000 when driving
• I bumped the max RPM of the engine up to 2700 unloaded and 2600 loaded
• Oil temperature stays around 180-200 consistently
• I installed a blue ox exhaust brake and build a maximum of 35 psi of backpressure
• Max boost I see under load is 25psi

Bus Details:
• My bus is heavy (35k lbs. total) and I flat tow a 4k lbs. jeep
• We also did an 18” roof raise and have a bunch of solar on the roof- so I catch a lot of wind.
• I re-geared the rear end to a 6.17 (from a 4.11) and unlocked 6th gear on my Allison MD 3060 so we top out at 75mph and cruse at comfortably at 65 (at 2100rpm)

I also developed a rear main seal leak around the same time as the blowby started. I’ve checked my air intake piping and didn’t see any signs of me dusting out the engine. Let me know if I am missing anything.

 

[ewo1]

I have the same bus as yours so hopefully brighter minds chime in and help you thru this as this for me is a great learning opportunity!

My bus had 6th open, 225hp HT motor and a fresh in-frame, 5k miles on it now.
rear is geared at 6.5, rolls 2100 rpm at 65 just like yours and at 70mph she is pushing 2250 rpm.

What were your numbers at 4.11 gears?

Slight blow by, blue but leaves no trail like yours.

It's interesting how you don not have an extended crank time and I do, 12-15 seconds of cranking before she starts and won't start when it 50 degrees outside.

I'll be watching your thread and hopefully you'll figure yours out!

Post a few pics of your bus...and what part of the world are you at?

 

[Josh S]

My bus was pretty gutless when I had the 4:11 gears in it. I was happy if I was hitting 55mph. I swapped the rear end at the same time I added the tune and that helped. I could get to 65 and could maintain 55 easier. After I changed the max rpm to what a standard DT 466E makes I have the performance that I enjoy now. I also "manually" shift my transmission so that I can run out each gear a bit more. With the way the transmission is programed now, it wants to shift far to early in each gear. I haven't found a shop that can change the shift points yet.

I have no issues starting down to 0*f without a block heater. it usually starts as fast as a car or pickup would start (less than 3 seconds). I replaced the rubber seals on all the hard-lines of the fuel system and the check-valve for the fuel return about a year ago. Before I did that, I had some longer cranking times.

 

[ewo1]

My bus was pretty gutless when I had the 4:11 gears in it. I was happy if I was hitting 55mph. I swapped the rear end at the same time I added the tune and that helped. I could get to 65 and could maintain 55 easier. After I changed the max rpm to what a standard DT 466E makes I have the performance that I enjoy now. I also "manually" shift my transmission so that I can run out each gear a bit more. With the way the transmission is programed now, it wants to shift far to early in each gear. I haven't found a shop that can change the shift points yet.

I have no issues starting down to 0*f without a block heater. it usually starts as fast as a car or pickup would start (less than 3 seconds). I replaced the rubber seals on all the hard-lines of the fuel system and the check-valve for the fuel return about a year ago. Before I did that, I had some longer cranking times.

Quck valve for fuel return…. You got me thinkng !

 

[skoontz]

Can't really add anything, but wanted to follow along as well, as I have a similar engine in my bus.

 

[Josh S]

Also, If I remember correctly, some of the hard-lines in the fuel system are under vacuum and you may not see any fuel leaking. With a cold-cycle it may be just enough to break the seal and loose pressure/ vacuum. I added a cheap glowshift pressure gauge on the dash and installed the sensor in-line with the schrader valve on the filter housing. I build pressure almost instantly when I start cranking the engine over (50-60psi) I figured that it would be a useful gauge to have for troubleshooting in the future.

 

[Omnibot2000]

Josh.

How is your coolant level holding?

Does it stop smoking out the blowby on hot engine if the rad cap is cracked loose?

 

[Omnibot2000]

I have the same bus as yours so hopefully brighter minds chime in and help you thru this as this for me is a great learning opportunity!

My bus had 6th open, 225hp HT motor and a fresh in-frame, 5k miles on it now.
rear is geared at 6.5, rolls 2100 rpm at 65 just like yours and at 70mph she is pushing 2250 rpm.

What were your numbers at 4.11 gears?

Slight blow by, blue but leaves no trail like yours.

It's interesting how you don not have an extended crank time and I do, 12-15 seconds of cranking before she starts and won't start when it 50 degrees outside.

I'll be watching your thread and hopefully you'll figure yours out!

Post a few pics of your bus...and what part of the world are you at?

Does your engine start good when hot? If you have a block heater, you plug it in even when 70 degrees does it start faster?

 

[Omnibot2000]

Josh,

More I think about this, I think pulling the head first is key. Clearly your pressuring the crankcase on hard pulls. Rear main seal could be tired and now leaking with those pressures, I personally think it would not leak if the blowby is reduced.

While not on the DT 466 engine, I have seen a headgasket let go into the crankcase without entering the cooling jacket. Compression gassing exit on the side of the push rods for the valve train. I've even seen external head gasket leaks where compression is blowing out the side of the block/head without entering the coolant jacket. Was pretty wild. Very rare it happens. Do an oil sample. Check for coolant. If clean. Pull the head. Inspect cylinders and pistons. Check for cracking depending on tune. Start with oil sample. Can possible do a cylinder contribution test to see if one hole is down.

 

[ewo1]

Does your engine start good when hot? If you have a block heater, you plug it in even when 70 degrees does it start faster?

My bus is a South Florida (Broward county schools) bus, they did not order it with a block heater, oil pan heater or temp heaters for inside the bus.

On any day that I am driving it, it will restart after about 8 seconds of cranking. No smoke at all out the tailpipe. Even after sitting for several hours. I'm guessing it's because the oil is still keeping the block warm.

Initial "cold" start, even on a warm day, she takes 2 cranking attempts of about 8-10 seconds each. I have even considered putting in a 3rd battery just to make sure I don't run them down when cranking. Both batteries are new right now, less than a year old.

 

[cadillackid]

are we sure its blowby producing the haze and not from the exhaust? ive seen injectors on HEUI engines going wierds produce a haze in the exhaust .. if it is just drizzling a little you wont get fuel knock or super early firing but fuel dripping into the cylinder on the exhaust stroke will produce a light haze from the exhaust esp under heavy power , high RPM.. where the ICP pressure is high and the injector may take a few milliseconds longer to close..

 

[shortbus4x4]

are we sure its blowby producing the haze and not from the exhaust? ive seen injectors on HEUI engines going wierds produce a haze in the exhaust .. if it is just drizzling a little you wont get fuel knock or super early firing but fuel dripping into the cylinder on the exhaust stroke will produce a light haze from the exhaust esp under heavy power , high RPM.. where the ICP pressure is high and the injector may take a few milliseconds longer to close..

Injectors would be my first thought too. Pull the dipstick with it running and see how much blow by is coming out of it.

 

[Omnibot2000]

are we sure its blowby producing the haze and not from the exhaust? ive seen injectors on HEUI engines going wierds produce a haze in the exhaust .. if it is just drizzling a little you wont get fuel knock or super early firing but fuel dripping into the cylinder on the exhaust stroke will produce a light haze from the exhaust esp under heavy power , high RPM.. where the ICP pressure is high and the injector may take a few milliseconds longer to close..

Generally you'll have more smoke out the tailpipe from my experience. However if fuel is making it passed the rings which is allowing us to see more blowby......an oil sample should pick up higher levels of fuel contamination.

With that all said, another question that I never asked. Is the engine making oil? In otherwords could the injector o-rings have failed allowing fuel to enter the crankcase thinning the oil. Happened on my powerstroke but at the time my crankcase vent was plumbed into the intake for the turbo to draw in the crankcase pressures so I would never have seen it.

It's the sudden rear main seal that started leaking when this all happened that pushes me to excessive blow by now maybe fuel dilution.

Oil sample and cylinder contribution test is my first thought of attack. Could pull injectors out and have them tested as well

 

[Josh S]

Thank you all for your help troubleshooting. I decided to bite-the-bullet and do my first in-frame rebuild. I did not have the time to do an out of frame rebuild, so my leaking rear main seal will have to wait until I decide to pull the transmission. All of the bearings looked good for the hours, I had one piston with a small crack on the face, the cylinder walls were polished to a mirror finish with no cross-hatch left, and there was a bunch of crud packed around the rings. Basically, it was time to do a rebuild. I am glad I did, because the engine has so much more power and low-end torque now. I used to have to keep the engine at 1800rpm or above when applying power, otherwise it would lug badly. Now I can drop down to 1500rpm without lugging and I have much more power. Steep grades where I used to have to drop down to 3rd, I can now take in 4th gear with no issues. I wish I had rebuilt the engine sooner. We have 2,400 miles on the rebuild with no major issues.

 

[cadillackid]

Thank you all for your help troubleshooting. I decided to bite-the-bullet and do my first in-frame rebuild. I did not have the time to do an out of frame rebuild, so my leaking rear main seal will have to wait until I decide to pull the transmission. All of the bearings looked good for the hours, I had one piston with a small crack on the face, the cylinder walls were polished to a mirror finish with no cross-hatch left, and there was a bunch of crud packed around the rings. Basically, it was time to do a rebuild. I am glad I did, because the engine has so much more power and low-end torque now. I used to have to keep the engine at 1800rpm or above when applying power, otherwise it would lug badly. Now I can drop down to 1500rpm without lugging and I have much more power. Steep grades where I used to have to drop down to 3rd, I can now take in 4th gear with no issues. I wish I had rebuilt the engine sooner. We have 2,400 miles on the rebuild with no major issues.

this rocks!!! sounds like the cylinders got washed out by excessive fuel.. the cracked piston is another indicator of high cylinder temp or fuel in the cylinder when it shouldnt be. im assuming you had your injectors tested / rebuilt while doungthe inframe? if not id want to watch it real close and maybe even send some oil to blackstone at your first oil change and have it analyzed.. look and see if theres more fuel in it than there should be.. first oil changed youd expect to see some metals consistent with bearings and rings seating in...

 

[Josh S]

I installed a fresh set of reman injectors when I did the in-frame. I also changed out my break-in oil at 1200 miles and took a sample of the oil when I did so. I will probably do oil samples from here on out. They are cheap insurance.

 

[cadillackid]

I installed a fresh set of reman injectors when I did the in-frame. I also changed out my break-in oil at 1200 miles and took a sample of the oil when I did so. I will probably do oil samples from here on out. They are cheap insurance.

sweet!! you are on it!! you should be good to roll for a long time!!!

 

[Omnibot2000]

Thank you all for your help troubleshooting. I decided to bite-the-bullet and do my first in-frame rebuild. I did not have the time to do an out of frame rebuild, so my leaking rear main seal will have to wait until I decide to pull the transmission. All of the bearings looked good for the hours, I had one piston with a small crack on the face, the cylinder walls were polished to a mirror finish with no cross-hatch left, and there was a bunch of crud packed around the rings. Basically, it was time to do a rebuild. I am glad I did, because the engine has so much more power and low-end torque now. I used to have to keep the engine at 1800rpm or above when applying power, otherwise it would lug badly. Now I can drop down to 1500rpm without lugging and I have much more power. Steep grades where I used to have to drop down to 3rd, I can now take in 4th gear with no issues. I wish I had rebuilt the engine sooner. We have 2,400 miles on the rebuild with no major issues.

Awesome. That rear main seal will probably keep going for a long while yet.

My wife's escape had a failed PCV and pressurized the crankcase pushing oil past the front crank seal. Replaced the PCV and had no issues with the seal yet. That was over 10 years ago.