I did an oil change 2 weeks ago and everything ran great, then on Monday, I went out for a cruise and my oil pressure gauge started bouncing down to 0 and back up. Figured it was the sending unit going bad. I have one on order from Cummins, but when I got home just to be safe I checked the dipstick and it wasn't showing anything, where as it showed I was in the safe zone after I did my oil change...

Just to put my mind at ease that I didn't somehow run the truck without oil, I drained the pan, and sure enough, my pan was full. I filled it back with oil and still no reading on the dipstick but my gauge started working again for about an hour then it started moving around on me again. What could be causing the dipstick to not read? The tube is fully intact and contected to the block so I'm lost

As a side note, I don't have any oil leaks what so ever. My entire engine and undercarriage is as dry and clean as can be. The only leak I have is from the hold down nut on my #5 injector, it's not really even a leak, it's just a few bubbles coming from the top of the nut and the injector body, which I'll be taking care of this weekend, when I get into the shop

 

I have no idea what would cause that, thats the weirdest thing I've heard off, maybe somehow your dipstick itself got pushed into the pull handle causing it to be to short to reach thats the only thing I can think would cause something like that, as for your gauge its the sending unit im almost 100% sure of that, unless its your pump but the oil pumps on 12 valves are a gear type pump and they dont wear out hardly ever.

 

Make sure the end of the dipstick isn't broken. Other than that u might have been a couple quarts low.

 

Ill have to look into it some more tonight, but I'm positive the end of the dipstick isn't broken. It's all intact and has the "safe" "add" marks and the little balled up end still. When I pull the starter this weekend to get new contacts put in, I'll check where the dipstick tube connects to the block to make sure it's 100%

Say I was a few quarts low, what would cause me to burn that much oil in 2 weeks? I have very little blow by and I had all my oil leaks fixed, and it's been leak free for a little over a month now.

 

Maybe, the oil is just clean and you just missed the wet mark on the Dip? I've done that before, myself.

 

 

cummins are 12 quart systems except for the 6.7 which is 13. after about 1.5 to 2 quarts of being low, oil disappears from the dipstick. your engine may not be leaking oil, it may be burning it off. Cadillac north-star engines are NOTORIOUS for burning oil and always needed to be topped off. Or you may be allowing the oil to "coke", an event when people do not allow the engines to cool off properly before shutting them off and the oil sits in the oil pan at such a high temperature it essentially turns to sludge. more common in diesels than gasoline engines, it can still occur due to improper maintenance or lack there of.

 

That would be nice it were that. I'd feel pretty stupid if that were the case



From what I know, the 12Vs are 11 quart systems with the filter. I'll have to look into that more to just ensure that I'm not running my system low. I'll have to look into the "coking" just to be safe. I know since I've had the vehicle it's had a turbo cool down timer and is usually shut down properly, but before me, my parents, who bought the truck new, more than likely never let the engine cool before shutting it off. I may have had the dipstick issue for awhile now, and I'm just noticing it now because my sender is on it's way out. But the plus side is, my new oil sender is here, I just have to pick it up from Cummins on my way home and get it on this weekend.

 

The IP holds around a quart so if you run your engine before doing your oilchange it will take about an hour for all the oil to drain from it. I usually pull the plug and leave it for a couple hours just to make sure I'm changin all the oil. Also yes it is 11 quarts

 

I do the same thing when I chang my oil. Pull the plug, go do some work around the house come back and finish the job.