1HDT sudden excessive blowby

[dcruiser666]

I'm on a road trip from New York to North Carolina and on the way down I noticed the engine idling a little rough while stopped at a gas station. I opened the hood and saw oil all over the turbo inlet (between the compressor and air box). I then opened the oil cap and there is heavy blow by. I'm not sure what happened during the initial part of the trip to cause this, I have checked that there is no restriction to or from the catch can and tried venting to atmosphere for a little while but it didn't help. There is too much blow by to leave it this way so I reattached the hose. The engine was consuming a lot of oil at this point so I was stopping to check the level every hour or so and top it up if needed.

Questions

- Other than this likely being internal engine damage, is there anything I'm overlooking that I can check/fix before I need to leave at the end of the week? I don't have a lot of time or tools with me but wondering if there is possibly something fixable or worth trying that I don't know about.

- I am assuming the worst case of engine damage, but there's nothing i can do about it while I'm here. I finished the drive not going above 60 to keep boost down and checking the oil level, it is actually running and driving quite well considering. Does anyone think there is significant risk of a catastrophic failure if I drive it back to New York like this? Oil pressure is good/normal, egt slightly higher than normal but not excessive, turbo is boosting normally with no strange noises, water temp is normal. Just bad oil consumption and a little smoke from the exhaust.

This engine ran very well for the years I've had it and I'm very good with maintenance. I'm really disappointed and confused about this...

I should also say the engine has an intercooler and g turbo running ~15lbs max boost.

 

[Eurasiaoverland]

I would say you've snapped a piston ring or cracked a piston. So really no way to know what's happening to the bores. They will most likely need attention so the damage might be done already.. but if a piston disintegrates then you're onto rod or bottom end damage.

If you have access to a diesel compression tester, that coukd condemn the engine. If a test checked out OK I'd be inclined to drive it back.

 

[mudgudgeon]

How long have you had a catch can on it?

Catch can can cause a restriction in the PCV which can pressurise the crank case and cause undue blowby and excessive oil consumption.
There's a few members who've had this issue.
Remove the restrictive catch can, remove the problem.

I would suggest removing the catch can entirely, either reinstall the PCV hose per original configuration, or vent the PCV hose straight to atmosphere. At least temporarily until you can get it home, or do some diagnosis.

saw oil all over the turbo inlet (between the compressor and air box

This is common with the 1hd-t and can just simply be an accumulation of oil vapors in the intake tube.
The PCV vents into the intake tube between airbox and turbo. Over time, the oil will seep past the clamped rubber hose at the turbo housing and hard pipe sections.
Once it's saturated, it will get progressively worse.
The intake hose and housing can be thoroughly cleaned up with degreaser then brake cleaner and reinstall it all.
If it continues to make a mess shortly after cleaning this all up, then you may have a turbo shaft seal failure.
While you have hoses off, check the turbo compressor for shaft play.

 

[Eurasiaoverland]

How long have you had a catch can on it?

Catch can can cause a restriction in the PCV which can pressurise the crank case and cause undue blowby and excessive oil consumption.
There's a few members who've had this issue.
Remove the restrictive catch can, remove the problem.

I would suggest removing the catch can entirely, either reinstall the PCV hose per original configuration, or vent the PCV hose straight to atmosphere. At least temporarily until you can get it home, or do some diagnosis.


This is common with the 1hd-t and can just simply be an accumulation of oil vapors in the intake tube.
The PCV vents into the intake tube between airbox and turbo. Over time, the oil will seep past the clamped rubber hose at the turbo housing and hard pipe sections.
Once it's saturated, it will get progressively worse.
The intake hose and housing can be thoroughly cleaned up with degreaser then brake cleaner and reinstall it all.
If it continues to make a mess shortly after cleaning this all up, then you may have a turbo shaft seal failure.
While you have hoses off, check the turbo compressor for shaft play.

Good point - on a turbo engine you check for blow-by by disconnecting the PCV hose, then there is no turbo scavenging effect and you are seeing what can only be coming from the crankcase.

 

[dcruiser666]

Thanks for the info, the catch can has been on since 2021 and I never had issues with it. I worked out the oil had to be getting in from there so I tried driving while venting to atmosphere for about 15 miles. The blowby is so severe the cabin was filling with vapors and didn't seem to affect anything. If I drive it home I'm considering getting a longer hose to vent it to the back of the truck, at least to reduce the oil consumption and not gas myself.

When I said oil on the turbo I meant a lot, its covered and has left a small spot on the ground. I also lost about half a gallon of oil in ~200 miles, probably a combination of burning it and leaking from the intake. I'm pretty certain after getting a little grounded that there is serious engine damage. The oil is jet black, which it has always still looked new at oil change intervals, I had never seen blowby from the engine before, and it never consumed a noticeable amount of oil. It basically ran like a new engine until this trip. The change is so dramatic and given the symptoms I think I need to accept it has s*** the bed. The real kicker is I had been planning to list the truck after the new year and this was going to be my last trip in it.

So.. I am possibly fortunate enough to have a friend of a friend down here to tow me back, but if it doesn't work out I think I'm going to vent to atmosphere out the back, consistently check the oil level, and hope for the best.

Also, in the off chance that someone in the area wants to buy it in this condition before Thursday let's talk, I'm in Yougsville NC and I'm done.

 

[Skter505]

How many Miles or KM? What were your max egt's and what was your tune like? Curious what went wrong to suddenly give up. You sure your turbo isn't leaking out all the oil? It's normal for the breather tube to have a somewhat oily mist when disconnected. Really need a compression and leakdown test before you completely write off the bottom end.

 

[dcruiser666]

The engine has around 250,000km and had the beb done at 213,000 before I installed it. I'm not that suspicious of a bottom end issue, at least as the cause of the initial problem. My egt is only post turbo but was never more than 550f. Tune is virtually stock, I dialed back the g turbo to 15lbs max and max fuel was increased a hair. It has been this way for roughly 3 years.

Very confusing, there was no sign that anything happened either, the only thing that made me look at the engine was a rougher idle when I pulled into the filling station. I had been driving the truck up until the day I left and nothing was out of the ordinary. The only thing unusual about the day this happened is I cold started facing down on a hill in ~8f and the oil pressure took longer than usual to read on the mechanical gage, maybe 20 seconds before it moved. I didn't notice anything happen then but I'm thinking the engine might have run without oil for this short time and caused a valve to stick/contact a piston or a ring to snap. Not sure if this can happen in that amount of time? Just theories.

This is a video I took shortly after I finished doing a minor refresh and installing the engine. It shows the amount of blowby from the filler I was accustomed to. I usually check this after an oil change to visually monitor any differences over time and it has been just like this since that video was made. Now if I do this there are plumes of vapor and oil sprays everywhere. It chugs out on one stroke and the idle pattern sounds like half a cylinder is missing. I'm familiar with acceptable amounts of blow by on other diesels I've owned, and what I have now is not that.



The truck has now been towed to its garage in New York and I will likely never drive it again. I will post it for sale in the classifieds soon in this condition if a currently interested party falls through. There's a lot of awesome stuff in this truck, a shame the engine is a problem now. I just don't have time or space anymore to deal with this.

 

[dcruiser666]

I forgot, re. if it's the turbo leaking oil. The leak starts at the top of the intake above the tubro so I believe it's coming from the pcv, I'm pretty sure it's not the turbo.

 

[Skter505]

That is unfortunate. Your description sure makes it sound like a cracked ring or land. I highly doubt the downhill start caused it but weird it took so long to get oil pressure, that does sound strange.

 

[ubguessin]

Did you ever get this issue diagnosed?

 

[dcruiser666]

No, I sold the truck a while ago now without investigating further.