I just bought my truck a couple weeks ago, and when I got it I knew there was fuel in the oil. Not just a little bit of fuel a whole lot of fuel. The oil reeked of fuel and was really thin and the dipstick was showing about 3-4 inches above the full mark.

The first thing I did was change the lift pump and change the oil. The oil that came out filled a 5 gallon bucket to within about 3" of the top, so I'd say that was about 4.5 gallons or so. I put 3 gallons of new oil in the truck and I checked the dipstick before I started it and it was over full but I didn't worry about that because I figured the oil filter wasn't 100% full and it needed to circulate to get an accurate reading. I drove the truck around the country some and noticed oil pressure dropping (on the crappy factory gauge) so I went home and checked the oil and it was way over full. In fact the level was past the part numbers on the dipstick.

I did some investigating and found that my injection pump was leaking into the crankcase, so I replaced that seal and changed the oil again. This time I got what I would guess to be about 3.5 gallons of oil out of the truck. I put 3 gallons of new oil in it and it still reads way above full. I've drove it quite a bit and the level doesn't seam to be rising now but the level is up in the part number part of the dipstick, probably 2" above the full mark.

Are there different dipsticks for these trucks? Is it possible that the dipstick tube has gotten slid further down into the pan?

As far as I know this truck has never had anything done to it, its as stock as you'll find one. Do any of you have any theories as to why my oil level appears way high when I know there's 3 gallons of oil in there? Last night I cobbled an old mechanical oil pressure gauge into the oil filter housing and with the engine warmed up, I've got 25psi at idle and 55 or so running down the road. If the oil was truly thinned out that bad, I doubt I'd have that kind of pressure.


Thanks in advance for any help.

 

I don't think you get an accurate pressure reading in that port. If I remember right the psi there is regulated.

 

I found this diagram of the dipstick.. well technically this one is for a 2nd gen but I bet its very similar. For those of you who've had your dipstick assembly out, is it possible for that tube that goes into the block to slide down in there too far?

 

how does the truck run? Excessive smoke? Is the smoke white upon start-up? I may leaking fuel into the crank some where else? Possible injectors?

 

Everything seams just fine other than the level on the dipstick. The level doesn't seam to be rising anymore (since I put the new seal in the pump) either.

Truck starts and runs fine, doesn't smoke. There's not oil blowing out of the crankcase vent or anything like that either.

My dipstick says part number 3916850 00 [1]
The truck is a 1990 and its a manual if that makes any difference.

 

When you put 3 gallons in, was the oil filter full? It holds a quart, you can never drain all the oil out of the engine completely, so, if you put in 12 quarts, you may have over filled it by more than a quart...Mark

 

3 gallons was total. I filled the new filter (pretty much all the way full) and put the balance of 3 gallons in the fill hole. I'm showing about 2" over the full mark, I doubt a quart one way or the other is going to do that.

 

You have the correct dip stick and I do not see any way that it can go farther in, unless the tube was cut or broken off. I tried to measure mine with a tape measure, but the result, about 29 inches is probably not that helpful. I think that you are filling somehow...Mark

 

29 inches is the tube measurement, or the dipstick measurement? I plan on measuring both of mine when I get home.

 

The tube, but it is not very accurate because of the tape measure. I am working on my hardwood floors right now (oh the joy ), but I will try to get a more accurate measure with a string or wire a bit later today...Mark

 

The tube that goes into the block has a pretty good shoulder on it. I can't hardly see it being installed too deep. The dip stick tube it some sort of plastic though. It could have been broken, and then shortened maybe?

I know the 2nd gen 12v dipstick is longer.

Anyone know if there is a difference between an IC and non-IC?

 

Mine reads a little high on a fresh fill with 3 gallons.

 

Ok boys I might be barking up the wrong tree here. I drove the snot out of that truck for about an hour and checked the oil again......level is up about 3/4" , smells like fuel now and some was dripping off the vent tube. I've replaced the lift pump but it guess there's a chance I got a bad one. Or at least that's what I hope it is. Even with the thin oil, I still had about 20 psi at idle, I thought that was interesting.

 

Does it run smooth? Slight miss or anything of the sort?

 

Not that surprising when you consider that fuel oil is closer to a lubricant than a solvent, although it is a pretty good solvent ...Mark