I have a Cat 311. Running machine the other day and oil pressure alarm went off. Checked oil level and it looked above full. Drained, changed oil, new filter. Ran machine 2-3 hours and alarm again, oil level is up. Haven’t had oil analyzed but thinking fuel in oil. What could be the cause? Thanks
Fuel pump leaking fuel in to engine more then likely
remove the cover on the valves and see the inyectors have a fuel leakes is a commun problem
I spoke with Cat service and they stated the only 2 places fuel could enter are the transfer pump (easier fix) or fuel injection pump (harder). Not sure why they didn't indicate injectors as a possibility.
They are not as they are outside the valve cover. Some engines it is a possibility tho
please the seria number
5PK01111 6LK04180
if you have this type of injector this is the problem remove the cover an you'll see the leak on the injector
I was thinking 311 no letter with a 3064 engine I stand corrected
You say "you'll see the leak on the injector" - how do you mean, what should I be looking for?
Remove the valve mechanism cover. Run the engine at low idle for a few sconds only. Be very careful of high pressure fuel spraying but look for fuel pi$$ing out from anywhere around the injectors or their fuel line connections. If the oil level is going up noticeably in 2-3 hours the leak shouldn't be too hard to spot.
Here’s a pic with valve cover off. Does it look as you thought? Injectors where they are doesn’t seem as though I’d be able to see a leak. Haven’t run it yet.
That is a 3064 the injectors are not under the valve cover just as I thought your problem is the transfer pump or the injection pump
Thanks, what is it with the transfer pump that causes the leak? I ordered a new O-ring and going to pull it off but not sure what to look for.
Apologies. I thought what sergioasmi posted above was what you have, obviously from the photo it's not. There is a pin (circled) that is not identified on the drawing below. That pin fits between the tappet and the piston. Wear in the pump body where the pin passes through it is the likely spot for a leak. There is no bush or seal at that point.
Thanks Nige. I’m struggling to see how the transfer pump leaking results in fuel in the case as it is bolted to injection pump. Regardless, if it is wear and leaking should I just replace it? Not sure if there is any way to confirm it is at fault once off. Also if it is not the transfer pump, what would the fault be with the injection pump? Thanks
Don't hold me to it but the lower workings of the injection pump are lubed using engine oil so thats how it can cross over atleast im 99 percent sure thats the case.
I am of the same opinion. Really need thepumpguy to chime in. He would know for certain.
I need to see exactly what the inj pump AND supply pump looks like to make an informed decision..
Thanks very much, hopefully one of these pics will work.
More
There’s a seal under the roller in the spump.. they get hard n leak.. To confirm, remove spump.. block the outlet w your finger, apply air to inlet & spray w soapy water or dunk it in water n look for bubbles.. They r rebuildable.. Also check the banjo bolt on the bottom.. 10 bucks says it’s full of sticks
Thanks for that. I have the diagram of the pump and attached it below, which part is the roller? I had the banjo bolt off but didn't see any sticks! How does that happen.
Nobody bothers to drain the sediment & water from the fuel tank on a regular basis. The banjo bolt is the most restrictive part of the fuel lines therefore crap gets trapped there. If you have an early 311 with no suffix letter then I show the transfer pump as a 5I- 7825. What is your machine S/No..?
5PK01111 6LK04180
Looks like I can replace the whole assembly $219.26 from Cat. But maybe I'll pull it off and see if there's a leak as thepumpguysc recommended before throwing parts at it...
Your machine is a grey market import 311A-model from the Japan-only market. The nearest equivalent outside Japan is a 9LJ-prefix machine of S/No 9LJ00262-Up. Attached the appropraite spare parts diagram for that fuel transfer pump.
Thanks for that. The diagram you added looks to be the same pump diagram I attached. Except yours shows the roller thepumpguysc refers to but not the seal?
I think your best bet at this point is to remove the pump on your engine and take a look. Using the equivalency chart I posted above is not guaranteed to be 100% acurate.
The supply pump is part of the injection pump parts group.. It’s a Diesel Kiki/Zexel pump.. If there’s a fuel inj. shop close by, they’ll rebuild it.. probably while u wait.. The seal is PRESSED into a hole & not easily extracted.. it takes years of practice to learn how to do it..(seriously) The seal is more than likely NOT on any breakdown.. again, years of knowledge..
The supply pump can be gotten directly thru Zexel.. there’s a name tag on the supply pump.. But it can be rebuilt for around 100.00.. depending on if the piston is bad.. either way, your gonna be 100.00 ahead if u take it to the local inj pump shop..
Thanks again! I'm in Vermont, there's not an injection pump shop within 100 miles. They quoted $150 plus I'd have to ship it there and back. Do you have contact info for Zexel? Can't seem to find them on the net. Thanks
When I said u can order it direct, I meant the fuel shop can order it directly from Zexel.. Looking at your pics, the name plate is missing off the s pump..which doesn’t help.. You’ll have to get all the #’s off the main pump name plate, call a fuel shop & they can give u the s pump #.. When you call an AUTHORIZED Zexel dealer they’ll punch the # in & all the components pop up.. Pump, Gov & Supply pump.. for your specific pump #..
If u find it IS a bad seal leaking fuel into the engine & u wanna fix it yourself, your gonna need the parts.. Kit is a DGK 301H. Comes w hand primer. 1 oring that goes under the inlet fitting. 1 mounting oring. 1 piston.. If it’s scored.. And of course, 1rod seal.. Compare the prices of the parts to the cost of a new s pump..
I see your point, that kit is not expensive from what I can see on the net. But does it include the seal under the roller you mentioned earlier? Im definitely lacking the years of experience to replace that.. When I spoke with the repair shop he said I could remove the supply pump with the lines still on, actuate the hand pump and if fuel leaked out that would confirm it was bad.
No it does not include the seal.. THATS WHY I wrote: 1 rod seal.. u can check it that way if your lines were long enough..?? Most machines I’ve worked on have rigid steel lines..w no movement..
Why ask all these questions before pulling the spump.?? Pull the damn thing & get back to us..
Haha, yes I hear you. Had time today so pulled it off. Left the hoses on and actuated the hand prime pump which resulted in fuel spraying out the top of the priming pump. I assume there’s seals in that that are bad? Not sure if that is the issue with fuel in the case. I tried pressurizing as you described on the bench but no bubbles. And yes, your $10 bet was a good one as there were sticks in the lower banjo bolt..