Isuzu 3ld1 blow by????

[RPF207]

My 2001 hitachi ex35u mini excavator has an Isuzu 3ld1 in it. I pressure washed the mini a bunch before I disassembled it to give it a new paint job and make everything newish again and after pressure washing it I found I had moved a bunch of grime over to the end of the crankcase vent tube and blocked it off. When I started the engine before knowing the tube was blocked I came around to the engine and noticed the dipstick was bouncing out and oil was coming out. That’s when I found the blocked tube. Cleared the grime away and everything back to normal.

my question is is there too much blow by? The engine starts and runs very well. In fact the glow plugs hadn’t worked due to what I believe is a bad relay or controller and it still started pretty good in 15 degree F temps without any aid or heater making me believe compression is fine and rings would be ok.The machine has 4500 hrs on it.

what’s your thoughts?

 

[Delmer]

You pressure washed it, if there's too much blowby then the area around the blow by tube will be oily very soon. If not, don't worry about it. The dipstick will blowout if there is no other place for the oil to go. If the dipstick is tight, something else will blow out.

I saw an old tractor at a consignment auction not too long ago, it was leaking oil from almost every possible place on the engine, EXCEPT the blowby tube, but seemed to run fine. Bought it cheap enough, drove it home, removed the oil pan and valve cover and pressure washed the engine inside. Runs great and uses no detectable oil and no noticeable blowby. The tube was plugged with soot and rust from neglect and low use.

 

[John C.]

The spec is one inch of water taken at the dipstick tube with no restriction on the crankcase breather tube and the engine at full load. In general an Isuzu engine has to be in very bad condition before it will read one inch of water. I've seen them run just fine at six inches of water but they would use a lot of oil.

 

[Birken Vogt]

My customers use a lot of these engines, and I have almost never seen one do anything bad. A couple of head gaskets compression into water here and there but almost no hard problems even after 20,000 hours.

 

[RPF207]

Thanks for the help, fellas!

 

[Kirk Palmer]

I have a IHI with a 3LD1 in it. It started puking oil out the dipstick tube, but the dipstick fits VERY loose. My crankcase vent tube is routed to the injection pump with a check valve in the line. I cleaned the check valve, wrapped electrical tape around the dipstick to tighten it up, and everything appears to be fine. As long as I don't have any blowby coming out of the oil fill cap I'm not worried.

 

[John C.]

I'm wondering how a vent tube could be routed to the injection pump. It might be behind it but I have no idea how it would be connected to a fuel system.

 

[Birken Vogt]

I know the hose he is talking about but never had to mess with it. I'm sure it just carries crankcase vapors from one area to another. I have had a few engines of this style where the dipstick would get loose.

 

[RPF207]

My dipstick is also very loose, it doesn’t rattle around in the tube but there is ZERO resistance when pulling it out.

as for the crankcase vents, there are three hoses. One from the governor case, one from the injection pump bank/cam area of the block, these two vent gases from those areas to the valve cover. Then the valve cover has a vent tube that vents everything outside. Here is a pic of the two vapor transfer lines on the “passenger” side of the engine....the pic is above for some reason. You can see the two lines running by the injector fuel lines up to the valve cover

 

[Birken Vogt]

The ones I take care of vent the gases to the intake to be burned, not outside. There is about a 1" diameter flat plate valve thing in the valve cover/intake manifold area. The valve cover and manifold are really the same part on these engines, or set of parts. I suppose something could happen to this valve but I have never seen it happen.