Iseki TS1610F - Oil gushing from breather cap

[larso1]

Howdy all you tractor nuts,
I just recently purchased this tractor, my first, for a real good price. Guess I know why now. Ha!

Anyway, need your help in diagnosing this problem. The motor starts real easy and runs well. No smoke after short warm-up. I run the tractor for about 5-minutes and oil starts to run out the breather cap on top of the valve cover in copious amounts, not just spitting out, but sort of gushing out. I've gotten a lot of conflicting advice from well-meaning friends on what could be the problem. Blow-by comes up alot in conversation. But others say a diesel wouldn't start easily if there was that much blowby, or a blown head gasket, or a cracked head.

So, I just performed a leak-down test on both cylinders and checked oil pressure with a new mechanical pressure gage.

Results: 22% leakage through front cylinder, 35% through rear cylinder. Oil pressure is 62-psi which I understand is pretty good.

I'm told by the guy who lent me the tester that 22% is good, but 35% could be causing me the problems. He thinks maybe it could have been overheated by the previous owner and that the rings on the rear piston could have lost their tension, or could be a broken ring. He said he's surprised there's no crankcase breather on these, and that might have eliminated the problem. It just seems like oil to the valve train isn't getting back to the crankcase fast enough. The only path for the oil to get back to the sump from the head is down the four push-rod tunnels. So, I ran it without the valve cover and could see that the oil wasn't returning very fast, but it didn't appear that it was being pushed back from the tunnel entry either.

So, that's where I'm at now. Guess my next step is to remove the head and check for a broken ring, cylinder wear, head gasket, etc. Interesting problem, but I'm up for it. Anyone have any other thoughts before I start? And, thanks in advance,

Bill in CO

 

[Bird]

Bill, sounds to me like you've covered the topic pretty well. I'm certainly no mechanic, but would speculate that some return holes (or tunnels) are stopped up. I've never needed to "flush" a diesel engine, but I think before I did a lot of disassembly, I'd be tempted to drain the oil, put in the appropriate (or just a little more) quantity of about a 3 to1 mix of diesel and motor oil, start the engine at idle, only let it run10 or 15 seconds, drain the crankcase again, replace the oil filter, and fill it up with fresh oil.

Now before you do that, let's see what some of the guys who know more about diesel mechanics than I do think of the idea.

 

[jinman]

I agree with Bird's advice completely. I'm also not a diesel mechanic, but as I read your post (prior to reading Bird's reply) I was wondering if someone may have used non-detergent oil in the tractor anc caused sludge to build up in the passages for oil. Surely, you could see oil bubbling back into the valve cover if you were getting that much blow-by. Do you think someone might have had the head off before and got the passages obstructed with gasket material or sealant. ...you just never know. Good luck. I'd give Bird's suggestion a whirl before tearing it down.

 

[larso1]

Thanks for the replys Bird and Jinman,
Yes, it has been suggested to me by someone that something may be plugged up near the bottom of the block, maybe around the lifter area. And that oil sludge build-up may have occurred from lack of use over a period of time. I drained the oil and squirted about a can of Berrymans Chemtool down the pushrods, but I couldn't get enough flow with the spray can to make it back up; it just went on through. I also changed oil and am using 15W-40 Rotella T. It took a long time to get the 3-qts. down the pushrod tunnels, but I've been told that these 2-cylinder Iseki's take oil real slow..so that may not be associated with my problem. A guy at work suggested the kerosene / oil mixture too. But the guy who let me use the leak down tester, who also owns an auto repair shop, said he's never been able to clean up sludge in a motor just by running diesel or kerosene through it. (I wonder if he's tried?)He said if it's a sludge buildup, I would need to get in there and clean it mechanically with a brush or ? He also said that it could very well be that problem. As for the head being off previously, it sure could have. There could be sealant in there plugging things up, hadn't thought about that. One drawback with these 4x4's is that the front drive shaft prevents you from removing the oil pan without removing the drive shaft. Very inconvenient. I still need to get manuals so I can proceed without screwing up something.

Bill

 

[jinman]

Bill, I don't know anything better than Berryman's Chemtool for cleaning sludge. If that didn't do it, I'd be looking for something other than sludge as the problem. I also thought about blockage that would cause more oil than normal to be supplied to the valve train. If the flow was more than the designed return.... I know it's "way out there" to suggest, but your problem doesn't seem "normal." It's starting to sound like a tear-down is necessary. Maybe if you can get the manuals they will shed some light on your problem. Hopefully someone with some real Iseki experience will read and respond to your post.

 

[em14]

I may have missed something, but, did you find any sludge in the head or on the valve cover when you had the cover off? ... Or did you find evidence that there was something there and it had been cleaned up? I would be very leery about thinning the oil and running the engine at all ... ever seen rods after they were run without the correct lubrication ... It has been my experience in rebuilding engines that sludge must be removed mechanically … Even after soaking in mineral sprits or parts cleaner, I had to scrub the sludge off with various devices such as screwdrivers, putty knifes, bore brushes and rags etc. If this engine is not allowing oil to return to the crankcase I wonder what else is going on ... this is a classical no oil change result ... but, before I would tear it down, I would certainly talk to an equipment dealer who handles Iseki equipment and see what, if anything, is unique to these Iseki engines and the oil problem ... I have a feeling you are going to be tearing this baby down and heading for a "hot tanking" at your local machine shop ... I presume that you can get parts and gasket sets ... Good Luck

 

[larso1]

Thanks for the continuing replies, guys,

When I removed the valve cover, there was no evidence of any sludge. Just a rough, oily cast iron surface like you'd expect. I too thought about too much oil getting up to the head. The only oil feed is an external 1/8" steel tube running from the block up to the head. I thought, maybe it was possible that a pressed in restrictor at the pump discharge could have worked loose or something. I've read on another forum where some models of Shibaura had a pressed in fitting on the end of the cam shaft that sometimes worked loose and fell into the sump. Result was oil pressure less than 10 psi. But they didn't have the problem I'm experiencing. I wonder if I'm missing some breather line that relieves the crankcase. Can't find one, and I've looked al over the block for it. But how do these operate correctly without one? I mean, if the oil has to return down the same path that crankcase pressure from the inevitable blowby has to releave through.... well, something just doesn't add up for me. Thanks again for the responses.

Bill in CO

 

[DK35vince]

If there is excess crank case presure,usually it would push the oil out the dip stick tube and not the breather on the valve cover.

 

[normde2001]

Bill, if you do a search on "Iseki tractors" you will find that a lot of the grey market/Yanmar dealers handle them. Maybe you can order manuals to assist in troubleshooting. Also, if your oil fill/ dipstick screws down maybe you can leave it loose and see if oil shoots out there. That will tell you if your crankcase is pressurized. I suspect there is a crankcase vent tube somewhere.

 

[Anonymous Poster]

Hi bill

Just a thought can you take the push rods out and try and clean the tunnels. You may get any excess gasket goo out of the way by doing this.

 

[larso1]

Thanks again for the suggestions guys,

The dipstick does screw down, and has a tight seal. I assume this is because these diesel crankcases do pressurize some (according to my mechanic buddy they all have some blowby), and the dipstick is right down there at top of oil pan level. I did check the dipstick oil level when this first happened. And yes, oil pushed out from the dipstick well too. The oil level sat there high at the opening for about 30 seconds, then you hear a gurgle sound and it falls back to normal level. Definitely pressure in the crankcase that isn't getting out. I suspect oil filling the pushrod tunnels finally drained back down into the sump and the excess gas pressure in the crankcase is then allowed to exit up the same path. I think I will, as you suggest, try cleaning out the pushrod tunnels before I do anything major like pulling the head. But I think I will need to remove the oil pan, and therefore the front drive shaft, first to see what's going on from that end too. Thanks again. Keep 'em coming if you have any more of these good ideas. If this thing has a crankcase vent, I'd sure like to know about it. That would be the problem for sure. I'll let you all know how things go as I get into it.

Bill in CO

 

[skent]

Check your Relief valve specs. Seems to me your oil pressure is running on the high side. most run in the 30's.

Oil pump is designed to provide adaquate flow/pressure at idle speed. At higher speeds, pump delivers more so pressure is higher, so relief valve is there to dump the excess.

I had a Opel GT that had a clogged Relief valve. When I added a Mechanical Oil Pressure gauge under the dash, It was always pegged past 80 until the engine was completly warmed up and idling, then it would drop to high 70's. Ended up busting the gauge line (copper tubing) and spraying oil all over the dash. Replaced the relief valve and would hover at 35 PSI forever and a day.

Could be your problem. Let us know.

 

[larso1]

Steve, thanks for responding. I was wondering about that oil pressure. Seemed kind of high to me too, but no-one else has commented on it, not even my mechanic buddy. This idea makes me feel like you're really on to something....it just makes sense that too much oil is getting to the head. I don't seem to have the problem at lower RPM's, but when I wind it up to 2000 or 2500, it's no time before the oil pukes out the breather cap. I will definitely look into this before tearing the motor apart. Thanks again,
]
Bill in CO

 

[larso1]

Further on the topic of high oil pressure, a friend here at worked asked if it was possible if the wrong oil filter could have been installed, or if it might be plugged up. Well, it could have, since a new one was installed on it by the seller when I got it. I don't know what the distribution circuit of the oil delivery system looks like, but seems to me if oil wasn't getting through the filter easy enough, it would just restrict the oil flow to the head, not increase it. On the other hand, if part of the discharge from the oil pump goes through the filter, and part goes to the bearings and head, then it could conceivably cause these problems. Just thinking out loud.

Bill in CO

 

[Kelvin]

larso1,

I can't tell you what your problem is; I can only tell you what my situation was (which sounds similar to yours).

My 3 cylinder 16hp Kubota diesel engine was blowing a heavy mist out of the valve cover breather tube. Then the mist turned to oil droplets, then progressed to a continuous flow of oil. I suppose if I didn't have a breather tube then it would have come out like you describe. My problem was that 2 of the 3 compression rings had gone weak due to a suspected overheat condition from the previous owner.

Similiarties Between Your Condition and Mine:

(1) Indications of good compression on the cylinder(s) closest to the radiator, and indications of weak compression on the cylinder(s) the fartherest away from the radiator.

(2) The engine always started just fine.

(3) The engine seems to run just fine, with seemingly plenty of power.

(4) The apparent "blow-by" got worse as the engine warmed up.

On a side note, I suspect that my overheat condition was caused by the previous owner using 100% antifreeze in the thermo-siphon cooling system (no water pump; no thermostat; otherwise a normal pressurized water cooling system) that's only supposed to have a 50/50 maximum mix.

On the positive side, when I did take my engine apart, the insides were in excellent condition. The engine was left in the tractor; the oil pan and head was removed so that the pistons could be removed. The pistons and cylinder walls were in excellent condition so all I did was replace the rings. I went ahead and rebuilt the head since I had it off (replaced the valve guides & seals, etc). I replaced the rod bearings, but since the crankshaft was left in place the crank bearings didn't get replaced. Overall it seems like I had a little over $1000 total into the rebuild. I had a local automotive shop that I use a lot perform the labor; I'm guessing that the bill would've been $1300 or more at the Kubota dealership.

Hope this helps,
Kelvin

 

[larso1]

Kelvin, thanks so much for the reply. Your situation does indeed sound nearly identical to mine, with the differences being I mine has only two cylinders and the cooling system has a water pump. I understand from a source that 60-65psi oil pressure is what I should expect with these Isuzu enigines. So I probably won't need to woory about main bearinggs either. I am sure hoping that what I find is the same thing you found, i.e., weak compression rings from an oerheat condition. Your cost for the rebuild sounds high if you did the rebuild yourself, minus the head work. Did you replace the rings and hone the cylinders yourself, or did you leave the whole job to the mechanic? My auto mechanic friend will do the head work, but I plan on doing everything else. I figure new rings maybe $100 tops, rod inserts maybe the same, and head gasket maybe $50.00?? I would expect my friend to charge me around $200 for the head work, assuming I don't need new valves.

Bill in CO