Shovelhead

Could be a stuck over-pressure by-pass valve in the oil pump. ???<br>

1993W250

is there any way to check the oil pump without pulling the engine?<br><br><br>laura

Alec

Maybe I missed something in the posts, but I would bet if you change the oil and filter and put in a high quality 15W40 oil the problem will go away -- at least temporarily.<br><br>It sounds as though your oil's viscosity is too low at operating temperature (either that or you have a crack in a casting, etc., that is opening up at high temps, which would be bad).<br><br>The white smoke might be a &quot;red herring&quot; but it makes me think un-burnt fuel, which makes me think possible fuel dilution of the oil. So when you change the oil, if you could send out a sample for analysis, that would be helpful. You could check for viscosity, fuel contamination, or excessive iron, aluminum, or copper particulates that would point to unusual wear of a particular engine component. If the oil analysis checks out okay, then I would have to start looking at internal engine components . . . [undecided]<br><br>Good Luck

1993W250

isn't unburnt fuel create black smoke? and yes the oil change did improve the symtoms, but its still not satisfactory. <br><br>anyway, i'm having the local cummins guy trouble shoot and fix it monday, whatever it is.<br><br>i'll keep you posted.<br><br>thanks for the help.<br><br><br>laura

RCW

Laura,<br><br>There are two things I would check. The first is the overflow pressure valve which is located in the cover to the oil cooler. The same cover that the filter is attached to. It is easy to do, pull the filter, remove the oil line to the turbo, then the attaching bolts and pull the cover. The bypass valve is in the top of the cover, on the inside about an inch or so below the oil line to the turbo. Locking pliers will pull the old one. Replace it with a new one, and that just taps in with a socket until it seats.<br><br>If that does not do it, then lower the pan, remove the oil suction tube from the front of the engine (inside the pan) and pull the pan and oil suction tube out and inspect the screen at the bottom and the bottom of the pan for chunks of rubber sealant used by Fram.<br><br>I suspect you will find it is the oil bypass valve with a chunk of Fram stuck in it (bad grammer, but you get the picture). The symptoms sound like a stuck bypass valve.<br><br>In case you do not have a book on the engine, the torque values for the oil cooler housing and the pan bolts are 18 foot lbs when you put it back together. Also, do not use any regular silicone sealant, use the Cummins gaskets and their silver sealant. <br><br>Regarding your smoke. White when cold is OK, white when fully warm and running is indicative of low compression. Your mileage is no where near what I consider to be rebuild time, so I suspect the white smoke is at cold start before it warms fully.

1993W250

thank you very much. i will check the bypass valve.<br><br>when draining the oil i could have sworn that i saw chunks. i've saved the oil and will run it through a screen for kicks and giggles.<br><br>thanks again.<br><br><br>laura

Redleg

Do you still have the filter? If so, did it appear to be intact? I would not discard it until you have the problem solved!<br>Don