New to me 940E mustang loader - have some issues

6t6cuda

Member
Hello,

Don"t know if this is the best place to post this, but the Ford forum has done we well in the past - cross posting with the repair tips forum.

New to diesels, so this is a learning experience to me... anyway let me tell you a story:

I just bought a 1996 Mustang 940E (Yanmar 4TN82E-S engine). it is in good shape, and tight.

Sorry for the long post but I want to put everything out rather tan going back and forth with "what have you done", "did you try" questions....

It has one problem I am sure is going to bite me big: it smokes A LOT out of the vent tube coming out of the valve cover.

It starts fine, appears to run fine - have not had the chance to do any real work with it yet...

I did a "tune up" this weekend:
1. Replaced the engine oil/filter, added "restore" to see if it would help with rings
2. Replaced the hydro filter
3. Replaced the fuel filter
4. Replaced the air filter - very, very dirty - filter check was popped.

It smokes a bit at start-up (white) out the exhaust but after a short warm up it is clear - but it always smokes (white) out the engine vent tube - this did not change with the "tune up"

Things I know or observed:
1. It has 1300 hours but the meter does not appear to be running now
2. I got it from someone who did not take the best care of equipment - price reflected that (somewhat)
3. Has been and was running real rough when I got it because the low pressure fuel feed (between the feed and the injection pump) was leaking - ran erratically - so the thing was "randomly" fueled for who knows how long.
4. There was a LOT of oil and dirt in the bottom of the engine compartment
5. The vent tube is leaking oil
6. the vent tube smoke is not water - did the mirror test
7. There is substantial pressure on the vent tube
8. It appears to have decent power, but I have not worked it and did not know what it should feel like "new"
9. When I replaced the fuel filter it did have some water in the bottom, about 1/3 full. Also had dirt in the bowl (it is a removable bowl clear filter on this engine).

From my research everything points to rings; but I want to make sure before I tear the engine apart - could it be anything else (simpler)

Few things I do not understand and would like to know:
1. If it was rings would you expect smoke to come out of the breather and the muffler? - it is only coming out of the breather after warmup
2. I know gas engines, but how do you remove the injectors and do a compression / leak down test? - do I need to replace a seal after I pull them? - I don"t want to damage them as they are expensive and harder to find than spark plugs... - is there an adapter that I will need to hook up the tester?
3. How do you do an engine RPM drop test on a Diesel? - can you unscrew the injector? - how do you measure RPM w/o a spark signal?

This will be a limited use homeowner machine so it needs to work, but will not be worked all that often and that hard - if I could limp it along for 200-300 hrs that would serve me well...
 
The Mustang 940 is a real good machine with a tough engine mine has over 6300 hrs on it with no major repairs and runs 150 hours between oil changes with no oil added. When you changed the air filter did you change the safety inner filter and look for signs of dirt getting past it? I think with the servicing you have done I would just work it and watch the oil level. Oil is still cheap compared to parts.
 
General diagnostics say white smoke on start up indicate worn valve guides and or valve seals.
Blowby indicates engine gasses getting past compression rings.If engine does not smoke or use large amounts of oil,you can use it for quite awhile...The oil control rings may be still ok.The slight compression loss from worn top rings shouldn't affect performance much.
 
How much do you want for your engine? I've thought off lots of projects for another one. Besides my skidloader I have one on my Cushman lawn mower it doesn't go any faster but will mow standing corn stalks.
 
Have not done much; sent the oil out for analysis we will see what they say...

Come spring we will see how bad it is and what I need to do; might build a smoke collector and vent it back to the intake just to deal with the smoke some...

Might be sorry I did not jump on a spare engine, but hopefully it will all work out...
 

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