# Oil Leak



## PatioDaddyo (Mar 20, 2009)

Howdy folks. Newby here so be gentle. Have a Companion, Sears, riding mower with an oil leak I'm not sure how to go after. When its parked, it drips on the exh pipe and muffler. Burns off when started next. I havnt been too worried as it never showed smoke when running. Replaced valve cover seal, same. Yesterday my wife was mowing some heavy stuff that almost killed the eng, and I thought the thing caught fire! Smoked like crazy. Came out of the heavy stuff still running and the smoke diminished, but I could see it dripping on exh tube. There is signs of oil further back of the valve cover but not dripping there.
Started it this morning, runs fine, burnt off the drips from muffler. Is there known troubles with leaks under load that wont show with no load? Crankcase pressure? I took off the breather, doesnt appear to be plugged. Would really appreciate some help guys.
Mower is about 15 years old. 12 hp,38" cut. Mower model# 917.259270
Tecumseh model & ser, 143406152, 00930.
I gotta say this is the toughest piece of equip't I've ever owned. Always change oil, and plug regularly. I hope I didnt kill it. Thanks for the assist.
Patio Daddyo


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## geogrubb (Jul 28, 2006)

First welcome to the forum;
If it is leaking on the muffler you should be able to see where it is comming from, head gasket, intake maifold, valve cover, etc. can you post a picture. If it smokes, out the muffler, when you first start it the problem is probably worn valve guides, if it is from oil on the muffler there is a bad gasket, and we need to find which one. First clean everything, check the oil level to make sure it is at the proper level, if it is overfull, smell it to see if it smells like gas, if so the carb is leaking, if not, start it and let it run for a short time, shut it off and check later to see where the oil is comming from, if no oil is visible start it to see if it smokes, if it smokes on startup it probably is worn valve guides. Post back with your findings. Have a good one. Geo


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## PatioDaddyo (Mar 20, 2009)

*Leaker*

Thanks for the feedback Geo. Smoke is not from the inside of muffler, just whats on the hot outside. I was just wondering about excessive pressure under heavy loads causing seals or gaskets to leak worse. Can a head gasket leak oil and not leak compression? I guess a trip to the pressure washer is next to get it as clean as I can. Thanks again. PDaddyo.


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## phillipmc (Jan 27, 2008)

Yes it is possible for a head gasket to leak oil but not compression in OHV engines. There is normally a ring of gasket around the cyclinder then another ring of gasket around the port for the rocker arms. Iv got a OHV Tecumseh engine with the same issue. Its a spare engine I have so I seen no need to fix it atm. A headgasket is fairly cheap just need a torq wrench and the torq specs to make sure its all tightened back down properly. Also valve lash specks.


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## PatioDaddyo (Mar 20, 2009)

*Leaker*

Thanks Phillip. Makes sense. Appreciate the feedback. Hopfully a head gasket set will take care of it. PDaddyo.


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## ya472 (Sep 10, 2009)

*Tecumseh 143406152 oil leak*

I recently purchased a well used Sears tractor and according to the owner, the mail lower crankcase seal was massively leaking.

He was right, until I removed the engine, degreased and removed the eight bolts holding the crankcase together. 

Three of the bolts were loose !

Half of the crankcase gasket was missing, the paper had disintegrated. (water had entered the crankcase when pressure washing, so that too needed to be cleaned up)


Otherwise, it is a great runnning engine. The interior parts still look new, compression is excellent.


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