frankogrly Posted November 21, 2022 Share Posted November 21, 2022 I have diesel fuel in the engine oil. Thinking of changing the oil and filter and driving home which is about 200 miles. Any thoughts? Frank O 01 Endeavor Link to comment Share on other sites More sharing options...
DavidL Posted November 21, 2022 Share Posted November 21, 2022 (edited) How did the diesel get in the oil? How diluted is the engine oil? How long was the diesel in there? Was it then run / driven? how much? I assume that issue is now fixed? Then, yes, the next step is to flush out the oil and replace. Then it can be started and driven. But do that before driving it 200 miles... Edited November 21, 2022 by DavidL 1 Link to comment Share on other sites More sharing options...
Chargerman Posted November 21, 2022 Share Posted November 21, 2022 As Dave mentioned, how did the fuel get in the crankcase, has that issue been resolved? If unknown I wouldn’t drive it any distance before rectifying. Severe damage can result. 1 Link to comment Share on other sites More sharing options...
jacwjames Posted November 21, 2022 Share Posted November 21, 2022 Read this post for some ideas https://www.irv2.com/forums/f123/2002-cummins-isc-is-making-oil-419978.html I didn't do any more searches but know from my experience in the mines that a bad injector is a possibility along with the injector pump. On a Cat engine we had a fuel leak in the injector pump that caused the engine to run away, bad stuff, luckily the diesel mechanic foreman was there and was able to stuff a rag in the air intake to kill the engine. Black smoke was just rolling out of the exhaust and filling the whole tunnel, engine almost caught fire. I was standing about 20 feet away and couldn't see the foreman. X3 on don't drive it until you figure out the leak. Pay me some now or pay ma a lot later. 1 Link to comment Share on other sites More sharing options...
Jdw12345 Posted November 21, 2022 Share Posted November 21, 2022 As jacwjames stated, I wouldn’t drive it any further than necessary if at all, could be a bad injector or injector o-rings or who knows, if you can keep it contained to just an injector, hopefully that will be the only issues, it would be extremely cheap compared to anything more. I remember on another forum a owner had a bad injector and ignored it, ended up putting a complete engine (ISL 400) in his coach. JMO. 1 Link to comment Share on other sites More sharing options...
frankogrly Posted November 21, 2022 Author Share Posted November 21, 2022 Not sure when the diesel got in the oil. I hadn't checked the oil level as the oil was changed about 2000 miles ago. I noticed the oil pressure a little lower than usual. Checked the oil level when I got to the campground and it was over full and is pushing out the breather tube. Engine is running fine so would guess it is the seal on the CAPS pump. Would rather have it worked on at home about 200 miles. That was the thought to change oil and filter and drive it home. The opinion from the group appears to be not to drive it even if I change oil and filter. Frank O 01 Endeavor 1 Link to comment Share on other sites More sharing options...
WayneC Posted November 21, 2022 Share Posted November 21, 2022 Head gasket? Would not drive it Wayne 1999 Signature ceaser Link to comment Share on other sites More sharing options...
DavidL Posted November 21, 2022 Share Posted November 21, 2022 (edited) So sounds like it had quite a bit of fuel in the oil. Hopefully no wear damage. The somewhat good news is that diesel has a little bit of lubricity on it's own. You might swap the oil / filter and then start it, stop, wait and get a good level indication on level ground. Then run it to see how much fuel is entering the crankcase. If noticeable, then I wouldn't drive it. A little bit won't hurt things. But if it were mine, I would be diagnosing the issue and ideally repairing that before running the motor (post oil / filter change). Edited November 21, 2022 by DavidL 1 Link to comment Share on other sites More sharing options...
WayneC Posted November 21, 2022 Share Posted November 21, 2022 24 minutes ago, DavidL said: So sounds like it had quite a bit of fuel in the oil. Hopefully no wear damage. The somewhat good news is that diesel has a little bit of lubricity on it's own. You might swap the oil / filter and then start it, stop, wait and get a good level indication on level ground. Then run it to see how much fuel is entering the crankcase. If noticeable, then I wouldn't drive it. A little bit won't hurt things. But if it were mine, I would be diagnosing the issue and ideally repairing that before running the motor (post oil / filter change). I mixed up fuel in oil,antifreeze in oil is head gasket Wayne 1999 Signature ceaser Link to comment Share on other sites More sharing options...
danwegand Posted November 21, 2022 Share Posted November 21, 2022 Had same problem happen to me. my 03 Monaco Windsor had 198,000 miles, the high pressure injector nozzles started leaking fuel into oil. the pump is middle of engine. it also could be leaky fuel line , bad nozzle or pump. our Cummins engine our considered mid weight, or not like larger tractors or 18 wheelers that can go million miles. Cummins protocol replace nozzles and fuel lines lst. then pump if problem is not fixed. I had to replaced all 3. about 14,000 . Just finished 2,200 trip runs like a top. Link to comment Share on other sites More sharing options...
ok-rver Posted November 23, 2022 Share Posted November 23, 2022 If you drove with oil coming out the breather tube, you were probably 50% oil/50% diesel or there about. Added over 20 quarts of diesel to the oil in 2,000 miles. 200 miles might add 10%, so a couple of quarts to the 24 quarts of oil. If running 50% diluted is going to cause damage, it probably is done. We had the oil changed about 100 miles after we purchased our 2004 8.3 Cummins, 50k miles. Drove 300 miles and oil level about 2 quarts high. Cummins ran our engine off 5 gal bucket with fluorescent die diesel. Checked injectors under valve cover first with no die and then found leak into oil at accumulator on CAPS pump. Cummins has a diesel in fuel ratio but I could not find it. If changing oil, you might go with a heavier viscosity and very carefully monitor how fast the oil level is going up. If you get 100 miles and have way two much oil, could you get another oil change or is it the middle of nowhere? I understand wanting to have a local mechanic you trust do the work. If they ever have to run fluorescent die again, it will be a lot easier to use the FASS pump with short lines from/to a bucket to supply the diesel. 1 Link to comment Share on other sites More sharing options...
jacwjames Posted November 23, 2022 Share Posted November 23, 2022 I looked on my oil analysis from JG Lubrication for engine oil. It will only report diesel if it is above 2%. Did a quick search and found a couple references of a max of 4-5% dilution. So on my rig if I add a quart of oil the level on the dip stick moves a fairly small amount. One quart of oil for me is 5% of volume for my oil change, so it doesn't take much difference in oil level for it to be a big problem as far as dilution. No idea how much it would take to be coming out of the dip stick but a it would way more then acceptable. Link to comment Share on other sites More sharing options...
frankogrly Posted November 23, 2022 Author Share Posted November 23, 2022 I am home and will assess the problem next month. I ran a little over 100 miles and had the oil changed again, then it was a little over 100 miles home. I haven't checked the oil level on the dip stick since I got home yesterday. If it wasn't coming up on Thanlsgiving and I wasn't so close to home I would have repaired it on the road. I am guessing it is the CAPS pump seal as the engine ran perfect. If that is the cause and the CAPS pump has to be removed I probably will replace the pump. as the coach is approaching 160,000 miles. After everything is taken care of I will do an oil analysis at the next oil change. Thanks to all that replied. Frank O 01 Endeavor Link to comment Share on other sites More sharing options...
jacwjames Posted November 23, 2022 Share Posted November 23, 2022 Glad you got it back home an hope there are no long term ill effects I'd suggest after you get the problem fixed and have an oil change done you run it for a couple hundred miles and pull and oil sample to make sure there's no metal in the oil which would indicate bearing failure. Bearing failure would be one of my concerns from running with the oil diluted with fuel. Keep a close eye on oil pressure, if you see it dropping shut it down, oil pressure would be a leading indicator of a problem. I have a Silverleaf VMSpc and actually have an alarm set for low oil pressure. Link to comment Share on other sites More sharing options...
frankogrly Posted November 23, 2022 Author Share Posted November 23, 2022 I am thinking of pulling an oil sample before I have it fixed to see what the results are. Then another after I have it fixed and driven a few hundred miles. I blew an oil cooler a few years ago and did a sample before and after the repair. Frank O 01 Endeavor Link to comment Share on other sites More sharing options...
jacwjames Posted November 24, 2022 Share Posted November 24, 2022 That would work, it will give you an idea on fuel dilution. Link to comment Share on other sites More sharing options...
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