L275 Oil Leak (3 cylinder engine)

cstewart77 · May 23, 2005

Thank you in advance for your help. I have a mid 80's L275 Kubota with about 900 hours. Recently I have noticed a slight oil leak on the front portion of the engine from what seems to be a failed head gasket. Are there oil lines in the head in front of the engine? Has anyone seen this before? The anti-freeze is fine and the engine runs as it always has without issue.

If you are familiar with these engines the oil collects on top of the block in between the head and the water pump housing...there is a flat spot.....and drains to the right side as you are sitting on the tractor towards the fuel injection block (for lack of a better term). It is a tough spot to see the leak; could it be valve cover gasket or timing cover gasket? It does not leak down the front of the engine.

Thank you for your feedback!

Chris

rbargeron · May 23, 2005

Hello Chris - To make a long story short - it is very possible it is NOT the head gasket.

Now go get a beer and sit back while I drag you through the long version.

I had a L345 a few years back that developed an oil leak at the front of the head - I was pretty convinced it had to be the head gasket so I took the head off.

It's not that big a job - everything is accessible once you take off the valve cover. On my engine (and I'll bet yours too) there is only one pressurized oil passage thru the head. And it is not sealed by a soft metal insert in the gasket - rather it has a special thick o-ring that sits in a hole in the gasket around the oil passage. It looked ok, but I figured it had to be leaking so I changed it. But the oil leak was not reduced.

I figured I must have damaged the o-ring putting the head on so I got another one and did the job again. Still didn't reduce the leak. So I looked closer at the engine.

At the front end of the block, the head covers all the way to the front edge, and the front timing cover reaches up to the top edge. With the head installed, only a very narrow bit of the block is visible, if any.

But what I found was that the oil was coming out at the top joint between the front timing cover and the block. There is a narrow face along there where the two parts meet.

Taking the front timing cover off is a major job. But with some small parts removed for better access, I used a dremel tool and ground out a tiny vee-groove along that seam (using a vac to grab the dust). The block is cast iron and the timing cover is cast aluminum. I prepared a bit of clean bare metal on both sides of the gasket line - the gasket is narow there and a little piece of it was actually gone (the leak source).

I mixed up some JB Weld epoxy and when it was starting to stiffen up I rubbed some into the corner and let it cure for a few hours. Presto!! No runs, no leaks, no errors, no major teardown of the front of the engine. Life is good. This repair has lasted several years. If it ever starts leaking again, the same repair could be repeated.

I think the basic problem is that the timing cover grows and shrinks differently than the iron block, and it works the gasket a bit. If the gasket is maybe narrow anyway, it can fail.

As always, prompt cheerful refund if info is bogus.

Take care,
Dick B

cstewart77 · May 24, 2005

Hi Dick,

Thank you for your response; I took a closer look at things last night....removed the altenator and fan belt to try to see things better....also took a few pictures that you can see here:

http://cstewart.smugmug.com/gallery/552347

It is not leaking from the timing cover/block connection but is coming from the head gasket....once running for a minute or two you can see it....I have a few pictures 'marked' up to where it is coming from that might be helpful. Send me an email if you don't mind and I will forward them to you...as I cannot host .bmp files on smugmug.com for some reason.

Thank you!

Chris
cstewart77@hotmail.com

rbargeron · May 24, 2005

If it's really coming out at the head gasket it may be that fancy blue o-ring near the front of the head.

Here's a quote from a 2001 post by Snell :

" This problem is very easily fixed - the front dowel pin that locates the head also happens to have the oil supply for the head pumped through it, and there is supposed to be an o-ring around the pin to seal it. This is a special blue colored ring (Kubota part#15221-33700, $1.45) that stands up to the pressure and heat involved - it's easily missed - Kubota has it on a different page of the parts book instead of putting it on the same page with the head gasket. - go figure"

rest of the thread is here

Take care & good luck