When I tried to startup on a -10 morning last weekend I had something happen that was new. I let the heat cycle run though as usual but when I tried to start it sounded like a few of the pistons swapped holes and there was a lot of smoke. It ran really rough for a few seconds than calmed down. I later found that the oil filler cap and dipstick had blown out and through oil out of the crankcase all over the engine. I have 41k on the 2003 truck.
Anyone got the answer?


Walt

i find it hard to believe the oil filler cap blew off. just sounds strange as it screws on. did you just have the oil changed and perhaps didn't tighten it? i had that happen to a friends truck at the dealer. was the dipstick all the way out? i would think it would take some serious pressure to do that..

It has been 1200 mi since last oil change. I have 5W30 in it. the dipstick was only out about 1 inch. It tossed out I would guess 2 cups of oil.

Walt

When I tried to startup on a -10 morning last weekend I had something happen that was new. I let the heat cycle run though as usual but when I tried to start it sounded like a few of the pistons swapped holes and there was a lot of smoke. It ran really rough for a few seconds than calmed down. I later found that the oil filler cap and dipstick had blown out and through oil out of the crankcase all over the engine. I have 41k on the 2003 truck.
Anyone got the answer?


WaltYour truck will like you alot better if you plug it in for at least a couple of hours when the temps get that cold. Opinions vary on the temp and the need for that, but even below 20F, it starts much easier, and at least sounds like it's easier on the engine. Dig out your winter cover for temps below 32F also; both your engine and your transmission will run closer to their operating temperatures. 5W30? The manual for my '03 doesn't list that as an recommended viscosity for any temperature. I agree with Diesel Power; it doesn't seem likely that the cap could come off if it was screwed on properly, or the dipstick come out if it was all the way in.

I agree that 5/30 oil is not approved for this engine. I dont think that would cause the increased pressures but who knows.
Ben

Is the vent for the crank case plugged?

Yeah, I would check the crankcase vent at thr right front of the engine, just above the RF axle tube, for clogging. Possible ice/snow?Is the vent for the crank case plugged?

Crankshaft Rear Oil Seal Leaks During Extreme Cold Weather Operation (-29 Degrees C/-20 Degrees F) (Modify Oil Separator) #03-06-01-008 - (Feb 27, 2003)

</TABLE>Crankshaft Rear Oil Seal Leaks During Extreme Cold Weather Operation (-29°C/-20°F) (Modify Oil Separator)

2002-2003 Chevrolet and GMC C/K Models

2003 Chevrolet and GMC C4500/5500 Models

with 6.6L Duramax™ Diesel Engine (VIN 1 - RPO LB7)

Built Prior To January 31, 2003

Condition

Some customers may comment on crankshaft rear oil seal leaks during extreme cold weather operation. Typically -29°C (-20°F) and below.

Cause

A restricted positive crankcase ventilation (PCV) system may be caused by frozen condensation, ice, or snow that has accumulated in the vent tube at the bottom of the generator bracket. In extreme cold weather, the vent tube may not be subjected to enough heat from the engine compartment to melt the ice or snow. Excessive crankcase pressure may develop and cause premature oil seal failures. While the oil leak may occur anywhere on the engine, the crankshaft rear oil seal is the most susceptible due to the larger surface area in which crankcase pressures can act upon. The excessive crankcase pressure may not be apparent in the shop as the vehicle warms up and the blockage in the vent tube thaws.

Correction

Create a secondary atmospheric vent path for the PCV oil separator housing using the following procedure. This location is protected from the elements and is not subject to freezing. A secondary atmospheric vent path was implemented to production in February of 2003.



<LI type=1>Remove the generator bracket. Refer to Drive Belt Tensioner and Generator Mounting Bracket Replacement. <LI type=1>Remove the positive crankcase ventilation (PCV) oil separator cover bolts. <LI type=1>Remove the positive crankcase ventilation (PCV) oil separator cover and gasket. <LI type=1>Drill a 10 mm (25/64 in) hole (1) through the back of the generator bracket. The hole (1) should be located higher than the vent tube (2). <LI type=1>Clean any debris from the oil separator housing. <LI type=1>Install the positive crankcase ventilation (PCV) oil separator cover and a new gasket. <LI type=1>Install the positive crankcase ventilation (PCV) oil separator cover bolts. Tighten Tighten the positive crankcase ventilation (PCV) oil separator bolts to 8 N·m (71 in lb).
Install the generator bracket. Refer to Drive Belt Tensioner and Generator Mounting Bracket Replacement.
Parts Information

<TABLE width="100%" border=1><TBODY><TR><TH vAlign=bottom align=middle>Part Number



</TH><TH vAlign=bottom align=middle>Description



</TH><TH vAlign=bottom align=middle>Qty



</TH></TR><TR><TD vAlign=center align=middle>97301457



</TD><TD vAlign=center align=middle>Gasket, PCV Valve Cover



</TD><TD vAlign=center align=middle>1



</TD></TR></TBODY></TABLE>

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

<TABLE width="100%" border=1><TBODY><TR><TH vAlign=bottom align=middle>Labor Operation



</TH><TH vAlign=bottom align=middle>Description



</TH><TH vAlign=bottom align=middle>Labor Time



</TH></TR><TR><TD vAlign=center align=middle rowSpan=2>J1945



</TD><TD vAlign=center align=middle rowSpan=2>Vent, Crankcase Auxiliary - Install



</TD><TD vAlign=center align=middle>C/K Models


1.7 hrs


</TD></TR><TR><TD vAlign=center align=middle>C4500/5500 Models


1.0 hr


</TD></TR></TBODY></TABLE>

I guess that I need to make a few additions to my original post so that I don't make myself out to be a fool.

First off the oil is 5W40 Rotella.
I have my front cover on.
I was out of town and had a extension cord along but could not reach an outlet.

The truck has started many times in temps much colder than these temps.

I can't explain what was different on this startup but the cap did come off.
There was also a puddle of oil were the breather vent dumps down after the truck had warmed up.

The one helpfull comment that I did see was that possibly the breather had been plugged. I had driven 275 miles in 0 to 8 degree temps with slush and snow on the roads the day before.
Walt

Well now we know the rest of the story. Hopefully it was just the plugged vent, and the problem won't repeat itself. Good luck.

Did you check the oil after this happened? I was wondering if you had a possible injector problem and filled the crankcase with fuel. With the oil level really high, I could see that scenario happening.