Engine Serial: 08Z94098 Engine Arrangement: 5R8357 My 'new to me' D7F military surplus dozer appears to be dumping fuel into the crankcase. Oil level was slightly high when I got it but it's rising fast and has the typical diesel smell. I might have put 2 hours on it since I got it a few months ago from the military surplus sales so no idea of how long this was going on. I sent an oil sample out for analysis and I'll cut the filter open when I get some downtime in the next few days. Hopefully there are no main bearing flakes or other metallic bits in the filter.... After reading thru the forum it appears the common issue is oil coming from the fuel transfer pump. Looking at the diagrams in my military parts manuals (attached in this post), it looks like a simple replacement of o-ring #3 part no: 4J8997 will fix it but asking the experts here to verify that's true. If I replace that o-ring, is it worth to do a field re-build of the transfer pump and replace all o-rings and such inside? I want to order all the right parts so they're sitting at the Cat dealership when I do some family travel these holidays....
What you need for your engine is a new fuel transfer pump, these are really just a simple fuel lift pump and cost only a few $$$$, the down side is what damage has unrolled to your crank, Diesel fuel in the oil takes out the main bearings and in the worst case will spin the mains and destroy your block, this lift pump is fitted to the intermediate fuel system and is common for this trick, you can roll in new main bearings in frame if you think something might be happening wrong, the thought of changing a few 0 rings is not the route to take just swap the pump and always check your oil level BEFORE you start up the engine, don't check it at the end of the days work as the fuel has all night to drain off in to your engine. p.s. your number 3 4J8997 will fix nothing chap.
I think I would at least order the following: #3-4J8997, #7-3D2824, #10-6J2419, and #12-5P8215. Then again not knowing what the pump looks like inside it could need more that seals? But like tctractors says a new transfer pump would be cheap insurance against the cost of major engine damage!
naa... one bit of diesel will not kill the caps,(assuming it still has oil, Hehe) worst problem is a runaway... that dear friends will kill it. replacing the lift pump is the best option... as it might cost 10USD more than the seals... Good luck
I just took a look at prices of those pumps. At local dealer a new 1W1695 pump is listed at $755.00 a re-man 0R3537 is listed at $543.00. Now if you feel lucky I see a off-brand pump for $89.13 or best offer. Now if it was mine I would be at least tempted to take it off and disassemble and see if the seal rings were the only problem. But that is because I'm pretty confident I would be able to determine condition of "hard parts". But then if downtime was critical..............
Thanks for the quick responses. Downtime is not an issue as it's a ranch dozer. Cat SIS didn't offer a breakdown of parts and I could only order a whole transfer pump for ~$800 out the door. That's why I sent the stuff from my military manuals. But I remembered reading on the forum about replacing o-rings to fix the issue but maybe that was for a different style transfer pump. The funny thing I went ahead and ordered all the o-rings and check valves earlier today (just like kshansen suggested) for about $35. I had other parts for my 325BL excavator to order so I just tossed these in the mix. I can't believe a transfer pump would be that hard to rebuild but I'll take a look at it when I get some time to go to the machine and wrench off the pump. Might be a bit due to family stuff and the holidays but I'll keep all informed. And yes, tctractors- I read a lot of your posts about trashing the main bearings so I'm curious what's in the filter.... more to follow.
Here's the breakdown of the 1W-1695 Transfer Pump as fitted to engines of Serial Number 08Z87550-Up. All the individual parts are available. Also the D&A in case you want to pull it apart.
Thanks, Nige- that's helpful.
I was able to get the filter open for a look inside. The ribbon is about a third of the filter so it's a lot of pics to see all of it. I'll add a few more of the same areas but at a different angle
A little closure but at a different angle to find any glittering shiny bits. There a few brassy flakes but not much.
Last pic is running my finger down the pleats. All I could get out was a bit of brassy dust. The magnet didn't pick up any ferrous material. Thoughts overall? I'll also keep the filter media in case anyone asks for a closer look at anything
So I went back out and played with the contaminates a bit and realized the brassy stuff was probably yellow paint as it was mushy when I probed it. You can see the other non-ferrous flakes better in this picture too.
You could even have a leaking fuel nozzle, but the transfer pump is the culprit. I wouldn’t stress about the crank, too much. Run it and start scheduled oil sampling. Monitor Or, go Asperger about it and drop a main and a rod. Take a look. Roll a set of bearings in the old girl. It’s a sweet tractor.
They're a pretty tough engine, and diesel in the oil doesn't cause bearing problems like antifreeze does. Diesel is still a lubricant, unlike many other contaminants. It just reduces oil viscosity, so the danger lies in high operating temperatures and heavy engine loading operations. You certainly don't appear to have been working it long and hard under hot conditions, so I wouldn't stress about the fuel dilution too much. The filter looks fine to me. I seem to recall about 6% fuel dilution is still an acceptable number. The 3306 holds plenty of oil, unlike some engines, where the oil quantity is marginal. Remember the bearings are tin-overlay aluminium, so if there's serious bearing damage you'd see a highly visible level of aluminium flakes in the filter media.
I couldn't agree more about doing a thorough check on all items before cranking the engine. My time in military aviation gave me some pretty anal pre-flight "check every fluid, pivot point, and overall look for any oddities" behavior that carried over onto my old iron. This is how I saw the oil level rise more than an inch, almost two inches, on the dipstick since last time I used it so I realized something was up. I just dropped the filter and took it with me full of oil since I didn't have my oil sample bottles with me at the time. After reading a bunch of threads of 3306's making oil I figured it was the transfer pump like you pointed out many times. I didn't realize it may even leak down when the engine is sitting which is good news to me since it may mean I didn't run it that much with the high levels of fuel in it. I agree diesel is still a lubricant. The old yellow sulfur smelling syrup diesel I grew up is probably has some lubricating properties but today's 'clean' stuff bothers me so I agree with TC that even minimal fuel dilution is something to be worried about. As for the bearings, I thought mains had copper/bronze/brass in them which is why I got a little concerned about seeing gold flecks in the filter. When I realized it was probably yellow paint, I felt a bit easier. But I'll monitor. I just got this dozer recently from military surplus so even thought it's got a lot of years on it, I don't think it has many hours. I only put a couple hours on the fuel pump hour meter since I had it floated in and most of those two hours was not under load pushing dirt. Those two hours were from getting her home, working a frozen pedal and a few other items straightened up before putting her to use. And then some family items kept me from spending time clearing our land so it's just been mainly sitting for a few months. Hopefully that's when most of the fuel infiltrated the crankcase. Agreed not stressing too much on it. I'm leaning towards getting the transfer pump fixed and doing an aggressive oil sampling. Thinking even cutting open a filter in another 2-3 hours and maybe at 10 hours just to see what's going on as I really don't have a lot of history on this machine. Once I get situated on some family matters and able to get busy pushing dirt. I bet I'll only put 2-3 hours of work on her at a time (and that's maybe 3-4 times a month) as it's an evening/weekend thing clearing brush on our land. (Is that about a tank of fuel per month? LOL!) Maybe I just need to build up my confidence and use her like she was built to be used. She is pretty sweet.
2 Points of interest here, the first one being that in the U.K. we can buy those lift pumps for low coins as in CPD and ITR parts that work very well and can be changed 10 times for the price of a pucker CAT part that was most probably built in China so get a grip, the pleats of your oil filter show flakes of White Metal so how brave do you feel???? you might want to change out the oil and filter and see how it fairs, but be warned all the rotating mass of the Crank, Flywheel etc, Rods and pistons are all weight that is running on the Main bearings that has no fun running in Diesel, people can all say it will be fine and those few bearing flakes are nothing and mean nothing, I am just saying in the last 6 years I have had to do big rebuilds on CAT engines due to fuel in the oil, if its only been run for 20 mins it might be worth the risk but don't think the bullet has been dodged, if the dilution is / was 10% or less the motor might hold up, I have pulled these engines open that showed about 2 1/2" of oil above the stick and the mains were scrap and the rear crank seal allowing fluid to pass into the transmission, this engine was running but what a din it made with no interest on running on it's own oil, you might be lucky I prey that you are with the fact that you have not really given it a hard shift, as you are going to monitor the oil and filter you need to forget oil sampling just cut the oil filter top off and look at the oil content of the remaining bowl then cut out the full length section of the pleats to check, the oil sampling is to long and drawn out for this type of issue, besides they will only say monitor at next oil change or something of little interest, best of luck.
I've had 3306s that had this happen in 100 degree weather and I just fixed the pump and changed the oil and rolled on...your filter looks good to me.
A thought.......... This tractor was ex-military. What are the chances that it sat for so long after the SLEP programme was done on it and before that The OP bought it that the seals in the transfer pump hardened up through lack of use.?
Leaking due to sitting for a long time makes a lot of sense. It's always a concern with older low hour military machines. I remember a while back there was a thread about a really low hour military D7G and if it was worth $77K or something like that. Dried up seals was brought up.
Hi Guys- Just a quick update as I've been consumed with a number of family issues the past month. In short, yes I'd love to find a reliable aftermarket transfer pump but haven't had the bandwidth to chase one down yet. And yes, I do believe dried seals on the transfer pump were the cause but of course I can't tell until I pull it off and look at it. As far as the engine goes, SIS shows the engine to be new in 1996 and the hour meter on the fuel pump only shows 423 today (it had 422 when I received it). I know the military changes hour meters without concern but I think this is the original because of the way the paint looks (no cracks/chips on the mating surfaces to show removal). Either way, I still need to determine if I replace the mains or not...just won't be a decision on my radar for a bit though. All the great advice (especially TC's) is highly appreciated so thanks for the input so far.
Just a thought, Based on my experience i never seen a main bearing set failed in a diesel engine due to lubrication issues, (unless it was due to contamination) Main Rods bearings yes, Hoo yes , usually they throw rod´s out of the block if u hear them knock and insist on running them. Recently i had my Mercedes OM606, with this type of problem, engine oil was going up instead of going dwn, replaced lift pump plunguer seal (more or less same system as CAT) and its fine now. I do not plan to look at the Crank mains or Rod bearings. If u wan´t to go that road, its a precaution, but look also the main rods, thats is where the system is weaker. regards
I don’t like the looks of the flakes of grey / white material in that filter. Looks a lot like bearings to me. I would be investigating further.
In these cases, an ounce of prevention is worth 10 lbs of cure……
I've been working hard to bite the bullet and embrace reality that replacing the main and rod bearings is the right (and only) thing to do. I don't have easy access to a shop so this may be a field fix. Called the local Cat dealer to see if they were interested and they said they are shying away from field work and would need to pull the engine anyway to get all the bearings because of the equalizer bar being in the way. At first I thought it was just Cat being Cat but I took a look at the equalizer bar area and agree it would be a bugger to get back there to remove the oil pan bolts. Not even sure if there is enough room to back out the oil pan bolts to get the oil pan off so coming back here to hear your thoughts on rolling in new bearings in the field. Does the engine need to come out or can it be done in frame without a lot of special tooling, cussing, and extra hands?
Costex has it for $85.00
The bearings can be rolled in without the engine having to be pulled out. Yes, the rear oil pan bolts are a PIA to get out and replace, but it can be done. I did several inframe engine overhauls in my D7F's.
Thanks, Dave. I'm setting up an account with CTP as I have a feeling I'll be using them more in the future. Oz- Thanks for the input on the inframes. I figured that was the case but the Cat mechanic made it sound otherwise. Once I get the belly pans off, I'm sure I'll be able to get to everything. One lesson I learned the hard way was to work on the difficult bolts first. Going after the easy ones first only to find there is one bolt in a back corner requiring a special tool is frustrating to say the least. Always hate putting everything back together because I couldn't get that one last bolt out...
We are poles apart here as I have totally the opposite experience with fuel mixing into the engine oil, the Big End bearing seem to suffer nothing while the Main Bearings have spun in the cylinder block, it might be the case on an 0M606 but I have never touched one of these engines or even know what they look like, on the CAT 3306 the effect of Diesel fuel mixing with the engine oil the results are near always the Main journals take the Hammer, we all do things and think things our own way and I am basing my comments on what I have found many times, I don't get the easy jobs in this game only the knacker jobs so have seen some wrecks.
The engines in the D6 and D7 are simple to do an in frame to, the oil pan and sump (that is the Plate) are not hard to remove, its more fun to get them back up without damaging the gasket, the Main Bearings will roll out and back in but you might need a hand to turn the engine to get the back 2 cylinders, I use the engine turning tool that fits into the starter motor location it is slow and steady, so use your brains, the Vee belts would need to be eased off as that can hinder the front bearings moving, always check and double check the thrust washers for the correct way out, CAT have made this task near fool proof on the later blocks, the torque set is the same for both Main and Big end bolts so nip up the Tang side first on all caps, on the Mains I do the ft lb bit first then the deg' turn set going from front to back on 1 side then across on the back cap from back to front on the opposite side.
Thanks, TCTractors- I appreciate the input and confidence on keeping this simple. Here is what I found in my Army manuals for replacing bearings in a D7G which should be the same 3306 in my upgraded D7F. Granted these procedures are for an engine removed and completely broken down in clean shop environment but I'm guessing they should also be useful when laying on my back and having dirt and oil fall in my eyes. Any special tools to rolling/prying out the old bearings? I've seen the little tee looking thing that goes in the oil port but I'm guess even a homemade pin will work. I'll look for the barring tool you mention but sure would be nice to just crank on a nut/bolt in the front pulley or such. Looks like the main and rod bolt tightening spec is to take to 33 ft-lbs then crank another 90 degs. I assume I can this by myself with a 3 ft breaker bar or will I need another person with a cheater? I have a decent cordless impact wrench but I don't like using impacts on these kind of jobs unless you think it's fine.
Ok, let me see if Im following along correctly,,, You have an engine that runs FINE. You have a leaky fuel pump diluting the oil. You have ONE hour experience on this machine. Now the internet has talked you into rebuilding the engine in a perfectly fine machine???? WHAT????? Just change/rebuild the lift pump, change the oil and RUN the machine. Watch the oil pressure and forget any of this happened, until another oil change and analysis tells to you be worried. Ive seen a ton of engines get fuel in them. Then be repaired and live LONG and HAPPY lives. With the same ol bearings they had beforehand.
Old Growth I agree with what you say and have done it a few times. But TC tractors is the best when it comes to these machines. He's been spot on for a few problems I had in the past. I do see the flakes he's talking about in the filters. Fix the fuel problem first then I think there's two ways to deal with this. 1 Run it and open up the oil filter every 50 hours to monitor. 2 Replace the bearings and not have to worry and wonder if it will blow.
The other factor to throw out there is that this machine was parked for an indeterminate period of time before it was sold in a military surplus auction. What that might have done, or how it was treated before being put into the auction, could also be a factor. It looks like what is basically a good machine and the OP wants to keep it that way.
A new bearing roll is a cheap solution to prevent a whole lot more, and a whole lot higher, set of expenses down the track, such as having to install a new crankshaft. Listen to tctractors, the mans got the track record behind him of being inside a multitude of Cats over many years.
At the very least, i would recommend checking all the bearings. The mains will show the most wear on the bottom halves and the rod bearings will be worn more in the upper halves. Not knowing how much it was run with the crankcase dilution is the real question as to how much, if any, damage has been done to the bearings. In the future, a spun bearing will cost you a hell of a lot more than checking them or changing them now
Exactly. That's what worries me. If I owned her for the last couple hundred hours and was confident the fuel leak just started to happen in the last hour or two, then yes- I'd just replace the transfer pump, change the oil and run her hard. But no, she was delivered fresh from the Army where she probably sat and sat for 20+ years with minimal usage after a complete rebuild by Cat. I distinctly remember looking at the oil when she was delivered and thinking it was a fresh oil change because there was still a bit of straw color to the oil. It was also a bit high (maybe 3/4" above full?) but that didn't bother me too much. It was less than a couple hours of running (most at idle when I was cleaning out the mud in the winch cable) did I see how fast the oil level was rising. It was over 2" high above full so who knows when the transfer pump started to leak and how long the crank turned with diluted lube. It could have been leaking only a couple hours at little to no load with me or over a few hundred hours pushing berms at the Army. So yeah, rolling in new bearings is either a) a waste of my time, b) good insurance or c) preventing an expensive failure turning into a catastrophic failure. We'll all find out when I get into her....
Old Growth, I totally agree with every word you have printed, but the poor chap who has paid out big for a very fine Tractor that is New Growth in CAT fettle is caught in a tight spot, the Tractor has no history in regards how long it has been suffering a Diesel sump, or how long it has been running with this fuel addition, the chap has the Brains to to find a real neat Tractor that will go a good bit for him, also the Brains to not be scared to safeguard his capital investment, if it was my Tractor I would have the sump off in a flash as I can pop those bearings out and fit new easy in a day and a half ley in the crap on Site, I hope the bearings are found to be like Brand New and any comment I have made is Total Rubbish, the owners mind will be glad that he checked the Crank but annoyed that it was all a waste of time, all it would cost is a lower structure gasket set and fresh oil and filter that has to be changed anyhow, there would be a time cost but it's his Tractor and his time and he seems to have the right minerals to tackle the job, how do you balance things and just because the Tractor runs well and sounds like a CAT it means nothing at this point, if he had been running the Tractor himself and noticed the oil up the stick one morning it might be worth the risk, all these comments about Big Ends and rods through the side mean nothing to me as it's the Main Bearings supporting the rotating mass that suffer in this case, I hope I have not offended you in any way and give you total credit for shouting out a Key Board Midland Banker, but the Tractor is worth the effort.
Dont ya worry. Its takes much more than the internet to offend me. Its good advice. Ill share my experience. I live less than 10 miles from JBLM. One of the largest military installations on the west coast. Ive bought/scrapped/salvaged and sold TONS of military iron. It comes in two forms. Its either royally screwed, or its abundantly rebuilt and about like brand new, but been sitting a long time. My bet is that this machine was pristine when it was parked. The seals dried up (possibly more seals also that he has not discovered yet) and recently started leaking fuel into the pan. Then the military stated the auction/liquidation process about a year ago. The machine was woken up and shuffled around till the new owner got it and that more than likely how long its been leaking. OP, whats the MFG date on the batteries that were in the machine when you bought it?
Old Growth- You're spot on. I have a bit of experience purchasing military surplus and I know you can get a gem almost as much as you get junk at these auctions. Being patient at these auctions is a virtue to not get bent. The dozer I picked up was original in the early 70's but went through rebuild, probably in the mid- to late-90's. I'm only guessing the rebuild date since the upgraded 3306 under the hood was made in '96 per SIS. But it's in really good shape so I took a chance and bought it knowing that things like seals, rubber hoses, and other non-metal bits would be the gotcha's. If popping on a new lift pump and rolling in a few bearings are my only issues for the next 500 hours, then I'm happy. But let me open her up and see what's inside. I'm with TC on this one hoping it turns out to be a non-issue. The dozer came without batts so I had to drop in a couple Cat 31's where those ridiculous 6T's sat. But that would have been a safe bet to at least determine when the last bit of decent preventive maintenance took place. Best I can tell is probably 3-5 years ago by the amount of fading on the oil and fuel filters. No rust, just not shiny like new. JBLM- it's a great place and I've been there a few times. Was just there this past summer. Even took a nice pic of the scenic backdrop since it was so clear. Definitely a great place to live.
That looks like the pic. on a beer can but can't remember what brand.
Ill give ya a hint, that is Mount Rainier! Thats pretty much the view from my place.
That's what I was thinking.
LCA078 Don't disappear on us we want to see how you make out. To many posters just disappear.
The only recent one that pops into mind is Busch. Is that the one? That's an amazing view to have from the house. Usually when I'm up in JBLM you can't see Rainier that clearly from base but that day it was beautifully clear. Took that pic with my iphone just standing next to the airfield. I'll do my best to take pics and keep this thread informative or at least entertaining. I've learned a lot from the experts here and it's a small form of payback to document how I used that knowledge to keep some old iron running. Hopefully it will help another owner down the road in the same bind.
Welder Dave,I’m thinking Coors beer?
On a different note,bearing in mind the pedigree of this tractor and its previous military owners,I’d be popping the hyd and tranny pump off and sticking seals in. Not a big job and a very cheap one, As to pulling the bearings out,it’s a rare tractor to find with such low hours.Just do it.Think of how happy you’ll feel knowing that the oil pump is good and that you’ve fitted nice new bearings on that std crank.
Nicky- I'm guessing your suggesting this because if the seals leak on the hydraulic and tranny pumps, then those oils leak into the engine crank case?
To rotate the Main Bearings out of the top location all the main cap bolts need cracking open about a 1/3rd of a turn or possibly a touch more to give a few thou' gap only, then you remove 1 cap at a time to roll out the bearings, they can be started with a blunt screw driver then rotated out using finger pressure holding the bearing to the crank as you rotate, roll out the bearing and refit a new one refitting the cap to firm then ease the bolts a small amount, the Big end caps are marked with a rod I.D. number and also have an I cast on them that should be facing towards the front of the engine, the I mark is on both the rod and the cap on the same side.
Thanks for the tips. I'm guessing trying to measure clearances with feelers or plastigage is kinda useless when rolling in bearings. I've only seen clearances being measured when block was upside down and the crank was resting on the block and not the caps. I assume the best thing to do is install same size genuine Cat bearings, torque-turn bolts and verify crank rotates freely? I'm guessing the big ends may have a slight back/forth wiggle once tightened that gives some idea of clearance but the mains will just be what they are?
I don't have any personal experience in surplus military equipment, but a local fellow bought one of those low hour Cat dozers, nearly perfect condition for low cost. He thought he hit the lottery. But the machine would leak like a sieve. As soon as he would get one seal fixed, a hose would blow. Then another seal would leak. Every rubber part was dry rotted. They finally parted the machine out. They made good money parting it out, but they still had to buy another dozer in the meantime. I've been told Cat does all engine durability testing with the engine oil diluted 10% with diesel.
You are looking for knackered bearings and a rough crank, start with the flywheel end caps.
There are plenty of non Cat oem bearings available to but that are good and a fraction of the cost. I’ve used Austrian Miba in the past and probably others that I’ve since forgotten
Plastigaging the mains can be done but it requires putting a hyd jack under a counterweight close to the one you are checking to support the crank in order to get an accurate result
Makes perfect sense.... and so obvious after you said it. Thanks for keeping it simple.