M923a2--8.3 has alot of blow by at oil dip stick

[Postman515]

Does the fluid coming out of the blowby feel like antifreeze? It looks like steam. My 929a2 was doing the same thing. It wasn't getting hot, no bubbling in fill tank, no water in oil but quite a bit of steam coming out of the blowby once warmed up. Problem ended up being the liner orings were installed dry and were leaking drops of coolant down the walls of the liner into the oilpan. Just enough to cause the steam but not accumulate in the oil. Ended up doing a complete in frame overhaul.

 

[gem1410]

The blow-by seems to be oil vapor with small beads of oil--dip stick is the same--small beads of oil being pushed out with oil vapor--no antifreeze smell--no water vapor seem on a mirror as per Patracy--at start up there is no blowby--takes 10 min of running time--antifreeze is dark and smells burnt in the fill tank--antifreeze level remains the same--engine runs great but also shows a rear main seal leak--slow dripping--Spurman and Patracy called it--ring problem--I looked at the truck before I purchased it--It started easy, ran fine and I did not see any blow by-- I missed it

 

[WillWagner]

Here's what I have seen.

This engine is used heavily in the vocational market, lots of trash trucks run them. For some reason, one of the local companies likes to use starting fluid, a lot of it! on 2 of 5 that ware brought in in this condition, stuck rings from over either injection, I have loaded the pizz out of them on the dyno and unstuck the rings, the other three needed to come apart and be unstuck, the customer opted to overhaul them. Bearings, heads, liners were all fine, they just had stuck rings. the carbon smelled like starting fluid when they were torn down!

These sit and just idle a lot, not good for the cylinder packs. If the engine was just idled or not loaded when operated, carbon tends to build up in the cylinders and in the turbine housing, that's why when the truck is taken out for it's first hot lap in God only knows how long, they will smoke on acceleration for a bit, then it will stop smoking heavily. If a mess of starting fluid was used to start it after sitting, low load and idling, the starting fluid tends to loosen the carbon and it sticks the rings in the lands.

Try driving it hard, lock the trans down is a gear so the engine is turning rated RPM and find a steep hill, maybe pull the injectors and put some marvel mystery oil in the cylinders, you might get lucky.

 

[TurboMustang370]

When driven like WillWagner describes, the truck has limited power, will not up shift and begins to backfire/pop out the exhaust stack. Ring issue or injector issue?

 

[Suprman]

Sounds like fuel starvation have you changed all the filters? Drained all the old fuel? Is it a recent problem.

 

[TurboMustang370]

it started during a deep freeze last winter. I changed the fuel filters, oil and filter and problem continued. Cracked the fuel lines at the injectors and seems to be Cylinder 3. Going to have the injector rebuilt, just hoping I'm not wasting time and money on the injector and having a deeper problem.

 

[gem1410]

Suprman,I find many of the trucks ** m923-a1-a2} have bad fuel lines--they suck air--have you replaced many of these and do you make up your own hoses--

 

[Suprman]

I have had a bunch of trucks that I replaced fuel lines and lift pumps on. The line coming off the large filter in the drivers wheel well area seems to rub thru often. I have seen the large filter element pretty gunked up before. I have a decent supply of misc hoses and lines I usually just use what I have.

 

[rww2]

Not sure if the truck has a crankcase filter. If so, check the cap spring and diaphram for issues causing high crankcase pressure
. Normally if you have bad rings you will experience fuel in your oil.