So I was enjoying an afternoon at the races on Saturday when I get a call from our Cat dealer’s SOS lab. He wanted to give me a heads up that the sample from our D7H that I had sent in a few days before was indicating significant fuel entry in to the engine oil. He later sent the results through and they were showing 7% diesel, a PQ index of 26 and high readings for copper and iron. We check the oil level religiously and were impressed that it never varied. Nothing in the filter that is visible to the naked eye. It has done another 12 hrs since, so might send another sample in now to get an idea of how quickly it is leaking. Where to then?..maybe swap out the transfer pump. It is “supposed” to have had new genuine injectors before we bought it.
What does the oil smell like.? with 7% fuel it should have at least a bit of a whiff to it. Pull another sample and have the numbers confirmed before pressing the panic button would be my first suggestion. Like the new injectors that the D6R (I think) allegedly had installed before you bought it.?
The lift pump is the cheap and obvious place To start.
when does the paper towel test start showing?
Unfortunately, I can’t do the sniff test or the paper towel test as I disposed of the oil a week ago because I wasn’t expecting this problem at all. New oil with only 12 hrs certainly doesn’t smell like diesel. Huge price range for new pumps…from $100 on eBay to $900 for gen. reman or $1280 for gen. new. Another sample in the post as we speak.
God, $918 for reman. From memory they only have 1 piston, 3 check valves, one seal and about 6 orings. Can you buy the seal individually?
one i prepared earlier Forgot i had this in emails
I’ll, more than likely, go the reman route for a little peace of mind. Certainly won’t be the eBay special. I have read some mention of a weep hole or tell tale but have yet to find one.
In a 3306 its a easy fix, noting terribly expensive to start panic. Probably its all related to the Mech Lift pump and or IP. As someone mentioned start by rebuilding the lift pump. (very often is the plunguer seal that quit) Those seals are on sale in various aftermaket dealers or at CAT. The other way fuel goes in is by the Injector Pump plunguers but that fix require the pump to be seen by an expert. In my opinion 7% diesel does not harm much the crank bearings, but this has been discussed here often, and others have other opinions. Depending on your pocket u might want to inspect them, or as Nige sugested, continue to watch the oil by sampling. Good luck with it.
Surprisingly, depending upon what 3306 document you look at, Caterpillar allows up to 3.4% or 4% fuel dilution.
Plenty of cheap as in less than 20 dollars electric fuel pumps that can pump 40 liters an hour .
Second test results arrived. To my mind, they have only made the situation even more confusing. The focus now seems to be on coolant ingress...high sodium? Around 50hrs ago we drained the ELC to replace a transmission cooler and refilled with ELI (no glycol) They say viscosity is below the threshold for DEO ULS that is only 12hrs old. Fuel is less than 2% which is what I expected after only 12hrs.
The elevated copper is probably the new trans cooler leaching. That sodium level is a concern.
Where is the sodium coming from qould be my question.? Because the OP is running Cat ELI as a coolant which surely ought to produce potassium if there was any coolant in the oil. Or is the 467 ppm of sodium a hangover from the 2300+ ppm the sample before and/or the cooler replacement.? Also there is a large amount of silicon for only 12 hours on the oil. I wouldn't expect it to be that high at 250...... Even the 33 ppm on the previous sample would have had me jumping up & down. Has anyone looked at the integrity of the intake system yet, even if only to rule it out.?
No, I haven’t closely checked the intake system. Elements are 260hrs old, outer would have been blown out a couple of times in that period. Is sodium a result of glycol reacting or some other element in the coolant? There would be no residual trace of glycol at the time of the second sample. After dropping the ELC we ran some Cat quick flush, changed the cooler, ran clean water for 10 hrs, dropped that and refilled with ELI.
Pull both elements and run a clean white rag around the intake tubes in that case. Maybe you need to ask your dealer (oil lab or otherwise) regarding the possibility of sodium vs potassium in ELI, the quick flush, or anything else that has been in there, simply to rule it out.
Yes, will do that in the next couple of days. The frustrating part is that, before receiving the oil test, I was confident that this was a very healthy motor. Starts in a heartbeat, no smoke except a puff of black at startup and when you feed it some beans, runs cool, uses no oil…although it now appears that it is being replaced by fuel, coolant or both. No oil pressure gauge but Cat did a TA2 inspection on the machine before we bought it and they have it at 50psi at low idle, 80 on high.
Cooling system pressure test maybe.?
Was thinking of that. I don’t have a test kit, what would you suggest I should be looking for?
I was thinking about a cooling system pressurizing pump actually. Pump the system up to 15psi or so and see if it holds steady.
So, the pressure test went well, pumped it up to 15psi and left for an hour with no drop at all. Air intake tube was clean also. I didn’t feel comfortable discussing test results over the phone… as soon as the call ends I would have another question for sure. I had seen that our dealer offers tours of their lab in Brisbane. Decided to take them up on their offer next time I was in the big smoke. They process some 600,000 samples a year, over 2000 a day, 95% of which happens in these two small rooms. Lots of automation and impressive equipment. The bloke who showed me around has been working in the lab for twenty years and was diesel fitter prior to that. I didn’t mention it above but we also replaced the engine oil cooler as well as the tx cooler. He was confident that the high sodium levels would be a carryover from this work. As Coaldust suggested, the high copper levels would also come from the cooler. He wasn’t too concerned about the silicone levels as they weren’t accompanied with high aluminium levels. The fuel contamination issue remains, so for now we will change the transfer pump and oil, get some hours up and take another sample.
Thanks for the update .
2000 a day is a lot of typing and making sure samples do not get mixed up, and loading and unloading machines.
Not these days, it's all done with bar codes or probably even QR Codes. Any time I see silicon in double figures on an engine sample it makes the hairs on the back of my neck stand up, whether it is accompanied by elevated aluminium or not. Who knows, the elevated silicon might just be accompanied by elevated aluminium in the next sample analysis.?
Paper towel test?
It's a quick & dirty test for detecting the presence of fuel in engine oil. Actually it works better if you use plain paper like you would use in a printer rather than a paper towel. Put a drop of oil on the centre and watch the diameter of the ring it makes. Compare that to the ring made by a drop of brand new oil. Note that the oil should be at normal engine operating temperature for best results.
Thanks Nige.
Thanks nige. I never do have the piece of plain paper so it's always paper towel.
The Paper Towel Test I use to detect even a hint of fuel in the oil is as follows, with a bit of Blue (common type) paper hand towel wipe the wet end of the Dip Stick on to it a few times, then set fire to the paper and see how it burns, if there is Diesel Fuel in the oil sample the paper will flair up and burn completely in a few moments, if its just oil on the paper the lit paper will burn around the oil and be reluctant to burn the oil soaked area, the difference is massive and a simple fool proof test, the comment on the high idle oil pressure of 80 psi sounds odd??? as for high Copper etc I would be dropping the Pan and Sump plate to check the Main Bearings only, the oil pickup basket on the pump is only a fine mesh and pegs up easy, but Fuel in the oil soon knackers a 3306 Crank so be as lazy as you want, the lift pumps are a daft price with a seal kit only being a few coins, some time ago we had a Chap with a low hour Military D7 with Fuel in the oil and me saying your bearings will be stuffed and loads of people saying to just change the oil and run it, I did say to cut the oil filters open and check for bits, well I seemed to have rattled the Chap some and against all sorts of other comments he dropped the sump and found the bearings on the way out Big Time, he fitted new bearings and saved his motor.
Thanks for those tips Tony, now keep in mind that Iam only a bush mechanic….and a pretty ordinary one at that. I did cut the filter open at the time and couldn’t see or feel anything visible to the naked eye. Based on what I saw at the lab yesterday, it would be well worth sending a sample for a filter gram analysis where they are able to identify microscopic particles and a likely source of origin. Before I inspected the machine the dealer identified an issue with the oil pump and replaced it with a genuine reman unit…any residue from this repair would also appear on the first test result. Later, he arranged for Cat to do a TA2 inspection…which I paid for. Test sheet shows engine at 80c when pressure readings were taken…in any case the numbers didn’t raise any red flags for them at the time. I may well end up having a look at bearings but first I need to stop fuel from getting in there.
@Queenslander Listen to TC on this one. He saved my motor.
Thanks for the post, somehow I missed your thread from earlier in the year. Did you post any follow up or pics of the bearings, or have I missed them as well? In my case, apart from the obvious peace of mind, it would be extremely interesting to see if a visual inspection matches the predictions of lab testing. I was more than a little impressed seeing the Filtergram testing, where samples of the filter pleat are viewed under a high powered microscope to determine size, shape, colour and possible origin of larger particles.
No- I just was IM'ing with TC on the backside telling him thanks because he saved my bacon and I never finished up my original post. I need to do that and will carve out time this holiday season. But here is a pic of my bearings. Granted my fuel dilution was probably way higher than yours and the engine run a lot longer but the result may still be the same: toasted bearings.
Scary stuff, kind of puts it all in perspective when you see photographic evidence.
So we replaced the transfer pump with a new genuine one, ran for 46 hrs and tested again…still has 3.9%. Have the fuel pump off now to have that overhauled. Dropped the oil pan and pulled a bottom main and big end bearing while we were at it. They look ok but Iam thinking we will replace them as we’re half way there now.
Those could look a little better.
With 8000+ hours on the engine they are never going to look perfect IMO.
We have the pump back ready to install. Just looking at the date codes on the bearings. My interpretation is that the mains were manufactured in 2021 which means they were likely replaced immediately before we bought it March 2022 and have done less than 500hrs. The rod bearings look to be 2019 manufacture and in the same condition as the mains. The scratches are very shallow and can’t be felt when you run a finger across and might have been caused by contamination when they were installed. As there is no guarantee that we can install them any cleaner, I am now thinking there may be no point replacing them. Thoughts?
Your dates are correct. I would doubt that damage was caused by contamination introduced during the install but not knowning how the install was done I suppose anything is possible. Fuel dilution can damage crankshaft bearings as a result of marginal lubrication caused by the viscosity reduction. Your bearings look pretty typical, just be happy you were doing oil analysis and didn't run it longer. 1. You already have it apart. 2. I'm assuming you have new bearings already on hand. Put them in would be my vote. Run 50 hours then do an oil/filter change and cut the filter for inspection.
Unless the crank was micro polished before bearing install and usual micro debris on surface, hands, I'm not surprised at those bearings. * As far as replacing, like the old Camel ad {If ya gott'em smoke'm }.
The Paper Towel Test that tells you all you need to know, is to get a sheet of Blue (its what I use) hand towel and wipe the soggy end of the Dip Stick (oil gauge) on it 2 or 3 times in the same area, then with due caution set fire to the paper, if it flares up and burns in a flash you have Diesel in the sump, if it's just E/Oil the paper burns around the untouched area leaving the oil stained part struggling to burn, the secret to all things oil sample, is always Cut open your filters and look for bits of Crank bearings in the pleats, I would have the sump off and be checking the Main Bearings instantly, you can swap all the Crank bearings in the D7H in Frame easy, the Big Ends will show little harm from the fuel ingress, the Mains will be showing harm, yes I know there is always loads of comments saying Run It or Waste of Time it will be fine, It's what I do as I am not Lazy and know the damage caused by running motors with Diesel in the oil, always check the oil level before starting the engine, the injector pump on the D7H was Trouble in lots of ways with the lift pump causing plenty of Drama, the A.F.Ratio control was equally problematic, then the Governor Control would wear out on the spinning bits to the point of lock up Infinity and Beyond, best leave things there for now.
And agree with TC, diesel fuel in any crank case will toast the bottom mains for sure. Just in age with high acid levels in oil, babbitt will flake away, diesel or gas engines. I've replaced A, B, and E model 3406 mains that had a trough of babbitt gone the entire radius of bearings, and everyone of those were engines that made oil. In gas engines the cam bearings are susceptible with age and have thin babbitt shell to begin with. If in there may as well replace, besides the oil draining down while looking up will keep your eyes and ears from squeaking.
And one thing to note, through the years I have found many with bottom main bearings with a six year spread by date from the top bearings, so that says some top bearings went in the round file, cat or cummins.
Thanks for the comments. I do have’em so I might as well use’em.
I know we are talking about Oil Sample issues but on the D7H Series motor you need to check 2 items every Service Point, the Fan Bearings as that big Fan eats them, then check the pipe work and Diaphragm in the Air Fuel Ratio Control on the Pump,I worked with a few of the LGP D7H Tractors and found out how to keep them pushing well, they will perform like a D8K with that wide blade I think it was 14ft 10", I think the engines were running around 230 bhp.
We’ve already replaced the fan bearing. When we bought it, it had new belts but fan and alt. pulleys were clagged, couldn’t stop it from squealing, so swapped the bearing while we were there. Combined with a decent pusher there aren’t too many trees that it can’t handle. Normally these big old Box trees are just a rotten shell and collapse as soon as you hit them, this one brought up a rootball the size of a small house.
I felt my exit hole, puckering up a bit, on that. Lol