Oil venting from valve cover breather


Old 01-03-07, 11:33 AM
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Join Date: Jan 2007
Posts: 3
Oil venting from valve cover breather

I have a Bolens H-14 (75-76 vintage) with a tecumseh 14 hp cast iron one lunger engine. Last year the engine was bored and piston/rings replaced. Last fall the engine started pumping oil out of the valve cover breather after running for 5-10 minutes. I checked the crank case breather to carb and seems to be clear. The engine does not smoke from the exhaust to indicate a broken ring. Compression check revealed 40 psi (low) but I don't know if the engine has an internal compression release for an accurate reading. The oil dip stick is also popping up thowing a little oil. The seal is worn from vibration. At a loss. Any help greatly appreciated...
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Old 01-03-07, 12:37 PM
puey61's Avatar
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
You likely answered your own question, just unknowingly. The dipstick seal must be tight in order to have sufficient crankcase pressure and vacuum. Any time you have a crankcase air leak the oil will want to take the path of least resistance and the breather is the least. With insuffiecient vacuum - which you have, it appears - oil will not be drawn out of the breather and will therefore blow out the breather hose. Replace the seal (O-ring) and you should solve your trouble.
Old 01-03-07, 01:13 PM
Thread Starter
Join Date: Jan 2007
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The seal on the dip stick had crossed my mind but it has always been some what loose. I have a tendency to Einstein things instead of looking at basics and I'm usually not that lucky. I'll seal the tube and see what happens...

Old 01-04-07, 10:19 AM
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Join Date: Jan 2007
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Smile No leak

Sealed up the tube and ran for 20 min with no oil leak. Looks like my luck is changing. Thanks for your help...
Old 01-05-07, 09:50 AM
cheese's Avatar
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Good call Puey61!

Glad you got the problem solved wglide, and thanks for the update!

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