This is going to be a little long, so bear with me.

My 06 PSD is quickly approaching 30k miles. I've done all the oil changes and followed the procedure outlined in the tech folder. All changes have been accomplished with truck in same location in driveway. First four changes, I put in 13.5 qts of oil. Oil level came up to halfway between the min/max lines on the dip stick. I check my oil level at least once a week (approx 300 miles) and it had always stayed at this level for the entire 5000 mile interval. However, after the fifth change at 20k miles (I changed at 1k and then again at 5k) I put in the same 13.5 qts of oil. Checked level and it came halfway up the marks as usual. About 500 miles after the change, I noted the oil level was above the max line. Not by much, but still over. The oil level was checked with the truck in the same location in the driveway as normal and engine cold as normal. Sniffed oil on dip stick and no hint of diesel smell. However, since I had put in the same amount of oil that I had always put in, I didn't do anything. Every check after that showed the same oil level just above the max fill line. Next oil change at 25k I put in 13 qts. Checked oil and it is midway between the min/max line. It stayed at this level for about 3000 miles. When I checked the oil level around 28k miles, it read just below the min line. I added 1/2 a qt and the oil level came midway between the min/max line. About 600 miles later, I checked the oil (2nd time) and now it reads just over the max line again. I haven't done anything and now at 29.5k miles it still reads just over the max line.

This has got me stumped. Can't figure out why the oil level would fluctuate like this. It's not a gradual change either. One week it's midway between the min/max line, the next week it's changed to the extremes I cited.

Anyone else experienced this or have an idea what's going on? I'm listening or I should say reading.

 

Mine sorta seems to do the same, I think its pretty normal, I just think different amounts of oil get caught up in certain places like the pumps or whereever else, sometimes some of it doesnt reach the pan for whatever reasons. Mines never drastically different though. Most of the time its in the right place.

 

It may be helpful to pull a mid-stream sample from the next oil change and send it to Blackstone for analysis. Make sure you have driven it enough to get oil and coolant hot before draining and pulling the sample - Blackstone recommends a certain amount of highway miles just before changing if I remember correctly. This should answer any worries about coolant or fuel contamination.

 

There is a small drain valve in the oilfilter housing that lets the oil go into the oil pan when you crack the filter open to do an oil change. For whatever reason it sometimes opens cold and lets the oil run back into the pan and makes your oil level read approx. a half a quart higher cold. It almost drove me crazy trying to figure it out. I always add 13.5 quarts per oil change. start it and then let it sit for 20 minutes before I recheck it. hits right in the operating range on the dipstick. next morning it's always over the top of the check area. When you start it and let it run for 20 again--it's right in the middle. Hope this helps.

 

Thanks npcc. That makes sense and is probably the best explanation. I guess I need to start checking 20 minutes after shut down to get consistent results vice checking several hours later when everything is stone cold. I'll also be pulling a sample per bis's comments just to make sure. Appreciate the feedback.

On a side note, I need to pony up and become a supporter. I've gotten more than my money's worth of help and information on this great site. Think I'll take care of that this week.

 

Some have reported that some of the "will fit" filters might also cause the oil in the filter housing to drain back to the pan.

 

I'm only using motorcraft filters so......... but that has been reported several times.

 

I've heard that as well Orig. However, that's not my case. I've only used Motorcraft filters thus far and don't plan on changing except for maybe IH. However, there's not an IH parts department convenient to me so it's not likely to change. Thanks for the input.