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Discussion Starter #1
The 430 is starting to puff some white smoke out the breather on top of the valve cover. If I hold my finger over the breather, there is a good bit of pressure coming out. I think it is using more oil than normal (not totally certain of that yet). Engine power is still good and the exhaust is very clear - no white, no gray, no black (except for the little burp when I engage the deck).

The tractor is 4 hours away - I visit once a month on weekends. On my next trip I am planning to take a heat gun with me to see if the exhaust ports are all the same temp. I tend to assume that crankcase pressure indicates blow by on the rings.

Any other possibilities to consider? Things to check?

Edit: The engine was rebuilt ten years ago - less than 500 hours.
 

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One thing I would check is the oil to see if there is any water/coolant on the dip stick. Also look in the radiator to see if you can tell if any oil is getting in there.
I am wondering if it is smoke or steam coming out?
 

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Sits for a month between runs may not be good for it. How long does it run when it is being used. It may not be burning off condensation in the crank case and gumming up the internals.
 

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Discussion Starter #4
Hmmm... I checked the oil right after I shut it down. There were some tiny bubbles on the stick when I first pulled it out. I was thinking air bubbles - maybe not?
 

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If there is water in the oil it will be grayish and not look like oil at all.
BTW all IC engines have back pressure.
Realize that when the piston is on down stroke it will create pressure within the crankcase.
That is the back pressure. Even your car or truck engine does this.
Hence the PCV system is there to suck that pressure out of the crankcase and burn it along with fuel.
If functioning properly there should not be vapors present out the valve cover.
In a car engine you can remove the PCV valve and clean it with carb cleaner and re install.
They tend to get plugged with those vapors accumulating in the valve.
Dont know on your engine but there has to be some type of PCV system in place.
 

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OK, let me take a stab at this. A 430 is a diesel right? Diesels don't have PCV systems because they don't produce enough vacuum to operate one. They use a closed crankcase ventilation system or CCV. It's just a breather to equal the pressure with the atmosphere. Given the infrequent use your tractor gets the white smoke could just be condensation vaporizing. You didn't mention whether the white smoke goes away after an extended period of running.

But you did say there seems to be some pressure so we may be looking at a loss of compression due to worn rings, piston or valves. Also while it is normal for a diesel to use some oil if in your experience it's using more now than ever before it may be time for a rebuild.

Or as others have said water in the oil may be a cracked head or blown head gasket.
 

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Discussion Starter #7
The oil was not white or milky at all - very clear - probably 20 hours since an oil change - still looks fresh. The air bubbles I saw did go away rather quickly and it was immediately after running. I'm guessing that if I waited a few minutes before checking, it would just be clear oil.

I checked the coolant level a few hours after running. There was no signs of oil floating it in either.

To answer the other question - the white smoke does not go away - it's there throughout the 5-6 hours of running.

The next time I'm there, I will check the oil and coolant again to be sure. I also have a thermal probe that I can check the temp of the exhaust. I'll see if one exhaust port is running cooler than the others. I think to check compression I need to pull the injectors - I'm not ready to do that right now on limited time, so that may be a winter project.
 

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The oil was not white or milky at all - very clear - probably 20 hours since an oil change - still looks fresh. The air bubbles I saw did go away rather quickly and it was immediately after running. I'm guessing that if I waited a few minutes before checking, it would just be clear oil.

I checked the coolant level a few hours after running. There was no signs of oil floating it in either.

To answer the other question - the white smoke does not go away - it's there throughout the 5-6 hours of running.

The next time I'm there, I will check the oil and coolant again to be sure. I also have a thermal probe that I can check the temp of the exhaust. I'll see if one exhaust port is running cooler than the others. I think to check compression I need to pull the injectors - I'm not ready to do that right now on limited time, so that may be a winter project.
I know you said the "white" smoke is present the whole time but how does it behave? As it comes out does it linger in the air and float away like a puff on a cigar or does it dissipate fairly quickly kind of like your car exhaust on a cold morning?
Thing to determine is if it is actually smoke or steam. That might help determine the source.
 

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Are you gaining oil
Does oil smell of fuel

Might do a BlackStone oil analysis .

Otherwise its excessive blow by past the rings
 

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I think that it's just classic "blow by" as you originally suspected. The rings aren't sealing for some reason. From your information, it sounds like you use it about 50 hours a year. It doesn't sound like it's much of a problem as long as you still have good power and clear exhaust. If it starts losing power then that may indicate that you need to do something with the rings. Until then, I wouldn't worry about it
 

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Discussion Starter #11
The white hangs around, so it should be smoke, not steam. Not gaining oil level or smelling any fuel in it.

So if it's "blow by", I'm just surprised that the exhaust is so clear and the power seems good.
 

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The "white smoke" is an oil film being carried by the blow by gasses. The gasses leaking past the rings and then pressurizing the crankcase escape from the crankcase up through the valve stem seals. They will carry a film of oil with them and then escape the head of the engine through that breather. Just classic diesel blow by. I have, in past lives, constructed filters to filter that vapor escaping the breather. I've not been very successful in doing that so I either live with it as long as it runs well or fix it when it no longer runs well. Just as a thought, have you checked the compression?? I'll bet it's low.
 

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Discussion Starter #13
I haven't checked compression. I don't have a compression gauge for a diesel and I'm thinking I need to remove injectors to hook one up? Other than curiosity, knowing that I have low compression wont do anything for me. I've still got good power, so I won't be doing a rebuild or anything heroic.

So low compression won't give me smoke out the exhaust?
 

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I haven't checked compression. I don't have a compression gauge for a diesel and I'm thinking I need to remove injectors to hook one up? Other than curiosity, knowing that I have low compression wont do anything for me. I've still got good power, so I won't be doing a rebuild or anything heroic.

So low compression won't give me smoke out the exhaust?

Nope.
 

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Usually a diesel engine will be tough to start,or have one or more cylinders not firing after a cold start,and belch white smoke (unburnt fuel) until it warms up,if the compression is below a certain amount--most have about 400 psi as a minimum..

My diesel pickup started belching white smoke last winter for several minutes after a cold start ,and was being a bear to get started,even with all the glow plugs working and good batteries,and it would skip like it had a dead cylinder or two..after awhile the smoking stopped,it ran more smoothly,and was able to be driven normally,then I noticed on a hard pull or highway on ramp acceleration ,it would starve for fuel and bog down..

I suspected I got a batch of watered down fuel ,but I saw no evidence of water in samples I took--then I thought perhaps I filled up at a place that didn't sell much diesel and may have gotten a load of "summer" diesel fuel last time I filled it in November...

I changed the fuel filter despite it not having more than a few thousand miles,and its a big one that holds about a quart of fuel,that made zero difference..

Then I discovered the electric fuel pump that had been added to the fuel line near the gas tank had failed,the engine still has a mechanical fuel pump but someone added the electric one to make for easier fuel system bleeding,and I did notice it ran better with both pumps working..

I replaced the electric fuel pump ,and it then started much easier,ran smoother,and only puffed white smoke for a minute if that..so I assume the injector pump is getting tired,and the added pressure of the electric fuel pump helps compensate for that.

The engine only has a "CDR valve" to help get excess pressure out of the crankcase and it is clean and functional,and there is hardly any blow by at the oil filler cap opening with it running,so I assume there isn't any bad rings or pistons in it--oil consumption is very low too,only a quart every 1000 miles or so,and most of that is lost from leaks..

I'm not familiar with your diesel but I assume it must have some sort of crankcase ventilation system that may not be functioning right,or perhaps it is being "flooded" with excess fuel from a bad injector or injector pump--usually you'll get a bad knock of an injector sticks open though..
 

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I haven't checked compression. I don't have a compression gauge for a diesel and I'm thinking I need to remove injectors to hook one up? Other than curiosity, knowing that I have low compression wont do anything for me. I've still got good power, so I won't be doing a rebuild or anything heroic.

So low compression won't give me smoke out the exhaust?
Is that engine turbocharged ?

Anyway in either case if it runs well it is what it is and its not like the first diesel to emit vapors and slobber a little.
Main thing is it runs as expected . A little CCV vapor is a right of passage for a diesel. lol.

Heck my 01 ram cummins with 275K steamed vapes out the slobber pipe quite well , VERY noticeable in winter BUT ran like a Champ ! Also good MPG's. However being a high mileage dodge everything around the engine was a rust bucket. lol .
 

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Discussion Starter #17
UPDATE...

SO I bought a HF diesel compression gauge and checked all three cylinders..

420 - 410 - 420 psi ....the best google searches I find indicate that spec is 355psi. This was done on a cold engine since it was pouring rain outside. I would think that compression would get better as the engine heats up?

So I'm not sure what to make of the higher than spec compression, but given the numbers that I got, the very small differential between them, and the fact that this engine was rebuilt a few hundred hours ago, I don't think I have bad rings or cylinders.

So where is the blow by happening? Is it possible to have bad exhaust valve stems that allow the valve to seal for compression but allow the hot escaping exhaust gases to go up through the valve stem into the valve cover? Would a hot engine lose compression?
 

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Well, that's certainly good compression on all cylinders. By the way that 355 psi is the minimum spec compression for that engine. 420 psi sounds fine for an engine that's recently been rebuilt. Yes, the compression should increase a little as the engine warms up.

So, I'm not sure that you have anything to worry about. The crankcase is going to get pressurized and that pressure needs to escape. It will escape through that vent in the rocker arm cover.

Your "problem" might be as simple as a missing hose. Some pictures of that engine show a hose from the vent in the rocker arm cover that runs back to a point in the intake. I would think that it would be pretty obvious if it was missing. Have you looked closely to see if there might be an open fitting in the intake somewhere that might accommodate that hose?? The solution for those blow by gases is to reintroduce them into the intake system so that they can "burn again". It's the same theory as the original PCV theory for gas engines ---- just dump them back into the intake so they get recycled through the combustion cycle again.
 
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