JCB 3c II fuel in the oil - fuel pumps?

[kardigen]

Hello
I think I have diesel fuel in my engine oil. It is not that easy to say for sure. I tried the cardboard test but it is not clear separation. But, I think I can smell fuel. I'm almost sure it is not coolant, the oil mixture is not that milky, it is rather thin and dark. The coolant level is stable.

My JCB 3c has Leyland 4/98NT engine. I wonder if it is possible that one of the fuel pumps would cause a fuel leak to the engine? I suspect the lift pump. Is it possible? Or it is unlikely that I'll have to tear the engine apart and check pistons? Any experience how to check if this is piston or sth else?

Thanks!

[Billy26F5]

If there's no milky effects or coolant visible in the oil it's fuel, it is possible for the injector pump to leak but I think CAV did a good job on the DPA seals, as leaks aren't common. It's probably a porous lift pump diaphragm, a pretty common problem as the rubber tends to age badly, often the fuel also leaks outside the lift pump. Pretty easy fix, you'll need a new diaphragm and depending on whether you remove the pump or not a gasket. You can do this without removing the pump provided everything is clean at all times. No tap on a JCB so you'll need to plug the pipe from the tank quickly to avoid loosing even more fuel. Don't run the engine until you've fixed this and replaced the oil and filter (If you can't get the parts quickly you can just do the oil change but your oil will not last long if you do that).
Good to see another 3CII on the forum!
Sandy

[kardigen]

Thanks, Billy for a quick answer.
I think I can see it is leaking outside, that's why it took my attention. I'll disassemble it then and check!

Also, I think need to clean up the hydraulic system. I think the filter or strainer is dirty because using the backhoe and supports takes quite a power - the engine is working pretty hard. I guess it also can have an impact on the clutch. It feels a little weak.
Do you have any experience in that matter too?

[Billy26F5]

Not a bad idea to clean the strainers (or strainer if your JCB is before 110759) and replace the filter but be ready for 43 gallons of oil as that's what is meant to be in there. The first thing to check for the clutch is the free play, as many have it incorrect. If that doesn't fix it you'll need to look at the clutch itself, being a Leyland (developed Nuffield) skid you won't need to split it for this, only lift the upper bell housing.
I strongly recommend you see the manuals (on the forum downloads), they're always handy to have when doing these things.
Sandy

[Matchless?58]

I recently cleaned my suction strainer. I found it to be blocked solid! I would also renew the main hydraulic filter while you have the oil out. I extended all the rams I could this sucks fluid into them and you dont lose as much. Unless of course you have decided to completely change the oil ?
I also removed the plate the drain plug is set into and cleaned out the tank . Lots of sludge in there so worth doing.
I think I lost about 90 litres. Bit of an expensive job but machine works so much better with a big increase in power. No one ever bothers or wants to spend the money on these old machines but they can still do a very useful days work when properly maintained. Next job for me is brakes.

[Billy26F5]

That's about half the oil. Good point about cleaning, always worth it.
Sandy

[UnclejakeNZ]

Hi gents, could someone please clarify if the 'increase in power ' after cleaning the hydraulic-oil filter could present as an apparent increase in engine power when travelling, or is it only an increase in digging power?

I seem to be able to dig pretty well with my 1988 3CX but travel up even a slight incline is very slow. I haven't serviced any of the hydraulic-oil systems as I assumed they had little to do with driving force to the road wheels.... but if the engine can be loaded by a blocked hydraulic-oil filter even when not operating the backhoe or front bucket I better have a look!

P.S. my non turbo engine seems very noisy. A new muffler didn't help. It's hard to tell where the engine noises come from as it seems to be a bit of clatter and drone from everywhere... but it's extremely uncomfortable to drive anywhere without hearing protection.

Cheers,
Jason

[Billy26F5]

Not a 3CX expert but it sounds like torque converter issues. Someone else might be better able to help you with that. As for the noise check the engine mounts otherwise as before can't help much more.
You'll probably find better attention if you post this in a new thread where the 3CX experts can see what you're posting from the subject.
Sandy